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Sample records for abnormal effective connectivity

  1. Abnormal cerebral effective connectivity during explicit emotional processing in adults with autism spectrum disorder

    PubMed Central

    Fonlupt, Pierre; Hubert, Bénédicte; Tardif, Carole; Gepner, Bruno; Deruelle, Christine

    2008-01-01

    Several recent studies suggest that autism may result from abnormal communication between brain regions. We directly assessed this hypothesis by testing the presence of abnormalities in a model of the functional cerebral network engaged during explicit emotion processing in adults with high functioning autism or Asperger syndrome. Comparison of structural equation models revealed abnormal patterns of effective connectivity, with the prefrontal cortex as a key site of dysfunction. These findings provide evidence that abnormal long-range connectivity between structures of the ‘social brain’ could explain the socio-emotional troubles that characterize the autistic pathology. PMID:19015104

  2. Abnormal effective connectivity and psychopathological symptoms in the psychosis high-risk state

    PubMed Central

    Schmidt, André; Smieskova, Renata; Simon, Andor; Allen, Paul; Fusar-Poli, Paolo; McGuire, Philip K.; Bendfeldt, Kerstin; Aston, Jacqueline; Lang, Undine E.; Walter, Marc; Radue, Ernst-Wilhelm; Riecher-Rössler, Anita; Borgwardt, Stefan J.

    2014-01-01

    Background Recent evidence has revealed abnormal functional connectivity between the frontal and parietal brain regions during working memory processing in patients with schizophrenia and first-episode psychosis. However, it still remains unclear whether abnormal frontoparietal connectivity during working memory processing is already evident in the psychosis high-risk state and whether the connection strengths are related to psychopathological outcomes. Methods Healthy controls and antipsychotic-naive individuals with an at-risk mental state (ARMS) performed an n-back working memory task while undergoing functional magnetic resonance imaging. Effective connectivity between frontal and parietal brain regions during working memory processing were characterized using dynamic causal modelling. Results Our study included 19 controls and 27 individuals with an ARMS. In individuals with an ARMS, we found significantly lower task performances and reduced activity in the right superior parietal lobule and middle frontal gyrus than in controls. Furthermore, the working memory–induced modulation of the connectivity from the right middle frontal gyrus to the right superior parietal lobule was significantly reduced in individuals with an ARMS, while the extent of this connectivity was negatively related to the Brief Psychiatric Rating Scale total score. Limitations The modest sample size precludes a meaningful subgroup analysis for participants with a later transition to psychosis. Conclusion This study demonstrates that abnormal frontoparietal connectivity during working memory processing is already evident in individuals with an ARMS and is related to psychiatric symptoms. Thus, our results provide further insight into the pathophysiological mechanisms of the psychosis high-risk state by linking functional brain imaging, computational modelling and psychopathology. PMID:24506946

  3. Neuronal substrate and effective connectivity of abnormal movement sequencing in schizophrenia.

    PubMed

    Zemankova, Petra; Lungu, Ovidiu; Huttlova, Jitka; Kerkovsky, Milos; Zubor, Jozef; Lipova, Petra; Bares, Martin; Kasparek, Tomas

    2016-06-01

    Movement sequencing difficulties are part of the neurological soft signs (NSS), they have high clinical value because they are not always present in schizophrenia. We investigated the neuronal correlates of movement sequencing in 24 healthy controls and 24 schizophrenia patients, with (SZP SQ+) or without (SZP SQ-) sequencing difficulties. We characterized simultaneous and lagged functional connectivity between brain regions involved in movement sequencing using psychophysiological interaction (PPI) and the Granger causality modeling (GCM), respectively. Left premotor cortex (PMC) and superior parietal lobule (SPL) were specifically activated during sequential movements in all participants. Right PMC and precuneus, ipsilateral to the hand executing the task, activated during sequential movements only in healthy controls and SZP SQ-. SZP SQ+ showed hyperactivation in contralateral PMC, as compared to the other groups. PPI analysis revealed a deficit in inhibitory connections within this fronto-parietal network in SZP SQ+ during sequential task. GCM showed a significant lagged effective connectivity from right PMC to left SPL during task and rest periods in all groups and from right PMC to right precuneus in SZP SQ+ group only. Both SZP groups had a significant lagged connectivity from right to left PMC, during sequential task. Our results indicate that aberrant fronto-parietal network connectivity with cortical inhibition deficit and abnormal reliance on previous network activity are related to movement sequencing in SZP. The overactivation of motor cortex seems to be a good compensating strategy, the hyperactivation of parietal cortex is linked to motor deficit symptoms. PMID:26780603

  4. Abnormal interhemispheric connectivity in male psychopathic offenders

    PubMed Central

    Hoppenbrouwers, Sylco S.; De Jesus, Danilo R.; Sun, Yinming; Stirpe, Tania; Hofman, Dennis; McMaster, Jeff; Hughes, Ginny; Daskalakis, Zafiris J.; Schutter, Dennis J.L.G.

    2014-01-01

    Background Psychopathic offenders inevitably violate interpersonal norms and frequently resort to aggressive and criminal behaviour. The affective and cognitive deficits underlying these behaviours have been linked to abnormalities in functional interhemispheric connectivity. However, direct neurophysiological evidence for dysfunctional connectivity in psychopathic offenders is lacking. Methods We used transcranial magnetic stimulation combined with electroencephalography to examine interhemispheric connectivity in the dorsolateral and motor cortex in a sample of psychopathic offenders and healthy controls. We also measured intracortical inhibition and facilitation over the left and right motor cortex to investigate the effects of local cortical processes on interhemispheric connectivity. Results We enrolled 17 psychopathic offenders and 14 controls in our study. Global abnormalities in right to left functional connectivity were observed in psychopathic offenders compared with controls. Furthermore, in contrast to controls, psychopathic offenders showed increased intracortical inhibition in the right, but not the left, hemisphere. Limitations The relatively small sample size limited the sensitivity to show that the abnormalities in interhemispheric connectivity were specifically related to the dorsolateral prefrontal cortex in psychopathic offenders. Conclusion To our knowledge, this study provides the first neurophysiological evidence for abnormal interhemispheric connectivity in psychopathic offenders and may further our understanding of the disruptive antisocial behaviour of these offenders. PMID:23937798

  5. Abnormalities of the executive control network in multiple sclerosis phenotypes: An fMRI effective connectivity study.

    PubMed

    Dobryakova, Ekaterina; Rocca, Maria Assunta; Valsasina, Paola; Ghezzi, Angelo; Colombo, Bruno; Martinelli, Vittorio; Comi, Giancarlo; DeLuca, John; Filippi, Massimo

    2016-06-01

    The Stroop interference task is a cognitively demanding task of executive control, a cognitive ability that is often impaired in patients with multiple sclerosis (MS). The aim of this study was to compare effective connectivity patterns within a network of brain regions involved in the Stroop task performance between MS patients with three disease clinical phenotypes [relapsing-remitting (RRMS), benign (BMS), and secondary progressive (SPMS)] and healthy subjects. Effective connectivity analysis was performed on Stroop task data using a novel method based on causal Bayes networks. Compared with controls, MS phenotypes were slower at performing the task and had reduced performance accuracy during incongruent trials that required increased cognitive control. MS phenotypes also exhibited connectivity abnormalities reflected as weaker shared connections, presence of extra connections (i.e., connections absent in the HC connectivity pattern), connection reversal, and loss. In SPMS and the BMS groups but not in the RRMS group, extra connections were associated with deficits in the Stroop task performance. In the BMS group, the response time associated with correct responses during the congruent condition showed a positive correlation with the left posterior parietal → dorsal anterior cingulate connection. In the SPMS group, performance accuracy during the congruent condition showed a negative correlation with the right insula → left insula connection. No associations between extra connections and behavioral performance measures were observed in the RRMS group. These results suggest that, depending on the phenotype, patients with MS use different strategies when cognitive control demands are high and rely on different network connections. Hum Brain Mapp, 37:2293-2304, 2016. © 2016 Wiley Periodicals, Inc. PMID:26956182

  6. Abnormal synchrony and effective connectivity in patients with schizophrenia and auditory hallucinations

    PubMed Central

    de la Iglesia-Vaya, Maria; Escartí, Maria José; Molina-Mateo, Jose; Martí-Bonmatí, Luis; Gadea, Marien; Castellanos, Francisco Xavier; Aguilar García-Iturrospe, Eduardo J.; Robles, Montserrat; Biswal, Bharat B.; Sanjuan, Julio

    2014-01-01

    Auditory hallucinations (AH) are the most frequent positive symptoms in patients with schizophrenia. Hallucinations have been related to emotional processing disturbances, altered functional connectivity and effective connectivity deficits. Previously, we observed that, compared to healthy controls, the limbic network responses of patients with auditory hallucinations differed when the subjects were listening to emotionally charged words. We aimed to compare the synchrony patterns and effective connectivity of task-related networks between schizophrenia patients with and without AH and healthy controls. Schizophrenia patients with AH (n = 27) and without AH (n = 14) were compared with healthy participants (n = 31). We examined functional connectivity by analyzing correlations and cross-correlations among previously detected independent component analysis time courses. Granger causality was used to infer the information flow direction in the brain regions. The results demonstrate that the patterns of cortico-cortical functional synchrony differentiated the patients with AH from the patients without AH and from the healthy participants. Additionally, Granger-causal relationships between the networks clearly differentiated the groups. In the patients with AH, the principal causal source was an occipital–cerebellar component, versus a temporal component in the patients without AH and the healthy controls. These data indicate that an anomalous process of neural connectivity exists when patients with AH process emotional auditory stimuli. Additionally, a central role is suggested for the cerebellum in processing emotional stimuli in patients with persistent AH. PMID:25379429

  7. Abnormal synchrony and effective connectivity in patients with schizophrenia and auditory hallucinations.

    PubMed

    de la Iglesia-Vaya, Maria; Escartí, Maria José; Molina-Mateo, Jose; Martí-Bonmatí, Luis; Gadea, Marien; Castellanos, Francisco Xavier; Aguilar García-Iturrospe, Eduardo J; Robles, Montserrat; Biswal, Bharat B; Sanjuan, Julio

    2014-01-01

    Auditory hallucinations (AH) are the most frequent positive symptoms in patients with schizophrenia. Hallucinations have been related to emotional processing disturbances, altered functional connectivity and effective connectivity deficits. Previously, we observed that, compared to healthy controls, the limbic network responses of patients with auditory hallucinations differed when the subjects were listening to emotionally charged words. We aimed to compare the synchrony patterns and effective connectivity of task-related networks between schizophrenia patients with and without AH and healthy controls. Schizophrenia patients with AH (n = 27) and without AH (n = 14) were compared with healthy participants (n = 31). We examined functional connectivity by analyzing correlations and cross-correlations among previously detected independent component analysis time courses. Granger causality was used to infer the information flow direction in the brain regions. The results demonstrate that the patterns of cortico-cortical functional synchrony differentiated the patients with AH from the patients without AH and from the healthy participants. Additionally, Granger-causal relationships between the networks clearly differentiated the groups. In the patients with AH, the principal causal source was an occipital-cerebellar component, versus a temporal component in the patients without AH and the healthy controls. These data indicate that an anomalous process of neural connectivity exists when patients with AH process emotional auditory stimuli. Additionally, a central role is suggested for the cerebellum in processing emotional stimuli in patients with persistent AH. PMID:25379429

  8. Physiological consequences of abnormal connectivity in a developmental epilepsy

    PubMed Central

    Shafi, Mouhsin M.; Vernet, Marine; Klooster, Debby; Chu, Catherine J.; Boric, Katica; Barnard, Mollie E.; Romatoski, Kelsey; Westover, M. Brandon; Christodoulou, Joanna A.; Gabrieli, John D.E.; Whitfield-Gabrieli, Susan; Pascual-Leone, Alvaro; Chang, Bernard S.

    2015-01-01

    Objective Many forms of epilepsy are associated with aberrant neuronal connections, but the relationship between such pathological connectivity and the underlying physiological predisposition to seizures is unclear. We sought to characterize the cortical excitability profile of a developmental form of epilepsy known to have structural and functional connectivity abnormalities. Methods We employed transcranial magnetic stimulation (TMS) with simultaneous EEG recording in eight patients with epilepsy from periventricular nodular heterotopia (PNH) and matched healthy controls. We used connectivity imaging findings to guide TMS targeting and compared the evoked responses to single-pulse stimulation from different cortical regions. Results Heterotopia patients with active epilepsy demonstrated a relatively augmented late cortical response that was greater than that of matched controls. This abnormality was specific to cortical regions with connectivity to subcortical heterotopic gray matter. Topographic mapping of the late response differences showed distributed cortical networks that were not limited to the stimulation site, and source analysis in one subject revealed that the generator of abnormal TMS-evoked activity overlapped with the spike and seizure onset zone. Interpretation Our findings indicate that patients with epilepsy from gray matter heterotopia have altered cortical physiology consistent with hyperexcitability, and that this abnormality is specifically linked to the presence of aberrant connectivity. These results support the idea that TMS-EEG could be a useful biomarker in epilepsy in gray matter heterotopia, expand our understanding of circuit mechanisms of epileptogenesis, and have potential implications for therapeutic neuromodulation in similar epileptic conditions associated with deep lesions. PMID:25858773

  9. Abnormal Functional Connectivity in Autism Spectrum Disorders during Face Processing

    ERIC Educational Resources Information Center

    Kleinhans, Natalia M.; Richards, Todd; Sterling, Lindsey; Stegbauer, Keith C.; Mahurin, Roderick; Johnson, L. Clark; Greenson, Jessica; Dawson, Geraldine; Aylward, Elizabeth

    2008-01-01

    Abnormalities in the interactions between functionally linked brain regions have been suggested to be associated with the clinical impairments observed in autism spectrum disorders (ASD). We investigated functional connectivity within the limbic system during face identification; a primary component of social cognition, in 19 high-functioning…

  10. Abnormal fronto-striatal functional connectivity in Parkinson's disease.

    PubMed

    Xu, Jinping; Zhang, Jiuquan; Wang, Jiaojian; Li, Guanglin; Hu, Qingmao; Zhang, Yuanchao

    2016-02-01

    Parkinson's disease (PD) is characterized by the relatively selective depletion of dopamine in the striatum, which consequently leads to dysfunctions in cortico-striatal-thalamic-cortical circuitries. It has been shown that the most common cognitive deficits in PD patients are related to the fronto-striatal circuits. In PD, most previous functional connectivity studies have been performed using seed-based methods to identify the brain regions that are abnormally connected to one or more seeds, but these cannot be used to quantify the interactions between one region and all other regions in a particular network. Functional connectivity degree, which is a measurement that can be used to quantify the functional or structural connectivity of a complex brain network, was adopted in this study to assess the interactions of the fronto-striatal network. Compared to healthy controls, PD patients had significantly decreased total functional connectivity degree for the left putamen and the right globus pallidum in fronto-striatal networks. Additionally, negative correlations between the fronto-pallial functional connectivity degree (i.e., the right globus pallidum with the left middle frontal gyrus, and with the right triangular part of inferior frontal gyrus) and disease duration were observed in PD patients. The results of this study demonstrate that fronto-striatal functional connectivity is abnormal in patients with PD and indicate that these deficits might be the result of motor and cognitive dysfunctions in PD patients. PMID:26724369

  11. Connectivity and functional profiling of abnormal brain structures in pedophilia

    PubMed Central

    Poeppl, Timm B.; Eickhoff, Simon B.; Fox, Peter T.; Laird, Angela R.; Rupprecht, Rainer; Langguth, Berthold; Bzdok, Danilo

    2015-01-01

    Despite its 0.5–1% lifetime prevalence in men and its general societal relevance, neuroimaging investigations in pedophilia are scarce. Preliminary findings indicate abnormal brain structure and function. However, no study has yet linked structural alterations in pedophiles to both connectional and functional properties of the aberrant hotspots. The relationship between morphological alterations and brain function in pedophilia as well as their contribution to its psychopathology thus remain unclear. First, we assessed bimodal connectivity of structurally altered candidate regions using meta-analytic connectivity modeling (MACM) and resting-state correlations employing openly accessible data. We compared the ensuing connectivity maps to the activation likelihood estimation (ALE) maps of a recent quantitative meta-analysis of brain activity during processing of sexual stimuli. Second, we functionally characterized the structurally altered regions employing meta-data of a large-scale neuroimaging database. Candidate regions were functionally connected to key areas for processing of sexual stimuli. Moreover, we found that the functional role of structurally altered brain regions in pedophilia relates to nonsexual emotional as well as neurocognitive and executive functions, previously reported to be impaired in pedophiles. Our results suggest that structural brain alterations affect neural networks for sexual processing by way of disrupted functional connectivity, which may entail abnormal sexual arousal patterns. The findings moreover indicate that structural alterations account for common affective and neurocognitive impairments in pedophilia. The present multi-modal integration of brain structure and function analyses links sexual and nonsexual psychopathology in pedophilia. PMID:25733379

  12. Connectivity and functional profiling of abnormal brain structures in pedophilia.

    PubMed

    Poeppl, Timm B; Eickhoff, Simon B; Fox, Peter T; Laird, Angela R; Rupprecht, Rainer; Langguth, Berthold; Bzdok, Danilo

    2015-06-01

    Despite its 0.5-1% lifetime prevalence in men and its general societal relevance, neuroimaging investigations in pedophilia are scarce. Preliminary findings indicate abnormal brain structure and function. However, no study has yet linked structural alterations in pedophiles to both connectional and functional properties of the aberrant hotspots. The relationship between morphological alterations and brain function in pedophilia as well as their contribution to its psychopathology thus remain unclear. First, we assessed bimodal connectivity of structurally altered candidate regions using meta-analytic connectivity modeling (MACM) and resting-state correlations employing openly accessible data. We compared the ensuing connectivity maps to the activation likelihood estimation (ALE) maps of a recent quantitative meta-analysis of brain activity during processing of sexual stimuli. Second, we functionally characterized the structurally altered regions employing meta-data of a large-scale neuroimaging database. Candidate regions were functionally connected to key areas for processing of sexual stimuli. Moreover, we found that the functional role of structurally altered brain regions in pedophilia relates to nonsexual emotional as well as neurocognitive and executive functions, previously reported to be impaired in pedophiles. Our results suggest that structural brain alterations affect neural networks for sexual processing by way of disrupted functional connectivity, which may entail abnormal sexual arousal patterns. The findings moreover indicate that structural alterations account for common affective and neurocognitive impairments in pedophilia. The present multimodal integration of brain structure and function analyses links sexual and nonsexual psychopathology in pedophilia. PMID:25733379

  13. Abnormal Functional Connectivity Density in Post-traumatic Stress Disorder.

    PubMed

    Zhang, Youxue; Xie, Bing; Chen, Heng; Li, Meiling; Liu, Feng; Chen, Huafu

    2016-05-01

    Post-traumatic stress disorder (PTSD) is a psychiatric disorder that occurs in individuals who have experienced life-threatening mental traumas. Previous neuroimaging studies have indicated that the pathology of PTSD may be associated with the abnormal functional integration among brain regions. In the current study, we used functional connectivity density (FCD) mapping, a novel voxel-wise data-driven approach based on graph theory, to explore aberrant FC through the resting-state functional magnetic resonance imaging of the PTSD. We calculated both short- and long-range FCD in PTSD patients and healthy controls (HCs). Compared with HCs, PTSD patients showed significantly increased long-range FCD in the left dorsolateral prefrontal cortex (DLPFC), but no abnormal short-range FCD was found in PTSD. Furthermore, seed-based FC analysis of the left DLPFC showed increased connectivity in the left superior parietal lobe and visual cortex of PTSD patients. The results suggested that PTSD patients experienced a disruption of intrinsic long-range functional connections in the fronto-parietal network and visual cortex, which are associated with attention control and visual information processing. PMID:26830769

  14. Abnormal cortical thickness connectivity persists in childhood absence epilepsy

    PubMed Central

    Curwood, Evan K; Pedersen, Mangor; Carney, Patrick W; Berg, Anne T; Abbott, David F; Jackson, Graeme D

    2015-01-01

    Objective Childhood absence epilepsy (CAE) is a childhood-onset generalized epilepsy. Recent fMRI studies have suggested that frontal cortex activity occurs before thalamic involvement in epileptic discharges suggesting that frontal cortex may play an important role in childhood absence seizures. Neurocognitive deficits can persist after resolution of the epilepsy. We investigate whether structural connectivity changes are present in the brains of CAE patients in young adulthood. Methods Cortical thickness measurements were obtained for 30 subjects with CAE (mean age 21 ± 2 years) and 56 healthy controls (mean age 24 ± 4) and regressed for age, sex, and total intracranial volume (TIV). Structural connectivity was evaluated by measuring the correlation between average cortical thicknesses in 915 regions over the brain. Maps of connectivity strength were then obtained for both groups. Results When compared to controls, the CAE group shows overall increased “connectivity” with focal increased connection strength in anterior regions including; the anterior cingulate and the insula and superior temporal gyrus bilaterally; the right orbito-frontal and supramarginal regions; and the left entorhinal cortex. Decreased connection strength in the CAE group was found in the left occipital lobe, with a similar trend in right occipital lobe. Interpretation Brains in young adults whose CAE was resolved had abnormal structural connectivity. Our findings suggest that frontal regions correlate most with cortical thickness throughout the brain in CAE patients, whereas occipital regions correlate most in well matched normal controls. We interpret this as evidence of a developmental difference in CAE that emphasizes these frontal lobe regions, perhaps driven by frontal lobe epileptiform activity. PMID:26000319

  15. Abnormal functional connectivity during visuospatial processing is associated with disrupted organisation of white matter in autism

    PubMed Central

    McGrath, Jane; Johnson, Katherine; O'Hanlon, Erik; Garavan, Hugh; Leemans, Alexander; Gallagher, Louise

    2013-01-01

    Disruption of structural and functional neural connectivity has been widely reported in Autism Spectrum Disorder (ASD) but there is a striking lack of research attempting to integrate analysis of functional and structural connectivity in the same study population, an approach that may provide key insights into the specific neurobiological underpinnings of altered functional connectivity in autism. The aims of this study were (1) to determine whether functional connectivity abnormalities were associated with structural abnormalities of white matter (WM) in ASD and (2) to examine the relationships between aberrant neural connectivity and behavior in ASD. Twenty-two individuals with ASD and 22 age, IQ-matched controls completed a high-angular-resolution diffusion MRI scan. Structural connectivity was analysed using constrained spherical deconvolution (CSD) based tractography. Regions for tractography were generated from the results of a previous study, in which 10 pairs of brain regions showed abnormal functional connectivity during visuospatial processing in ASD. WM tracts directly connected 5 of the 10 region pairs that showed abnormal functional connectivity; linking a region in the left occipital lobe (left BA19) and five paired regions: left caudate head, left caudate body, left uncus, left thalamus, and left cuneus. Measures of WM microstructural organization were extracted from these tracts. Fractional anisotropy (FA) reductions in the ASD group relative to controls were significant for WM connecting left BA19 to left caudate head and left BA19 to left thalamus. Using a multimodal imaging approach, this study has revealed aberrant WM microstructure in tracts that directly connect brain regions that are abnormally functionally connected in ASD. These results provide novel evidence to suggest that structural brain pathology may contribute (1) to abnormal functional connectivity and (2) to atypical visuospatial processing in ASD. PMID:24133425

  16. Abnormal Connectional Fingerprint in Schizophrenia: A Novel Network Analysis of Diffusion Tensor Imaging Data.

    PubMed

    Edwin Thanarajah, Sharmili; Han, Cheol E; Rotarska-Jagiela, Anna; Singer, Wolf; Deichmann, Ralf; Maurer, Konrad; Kaiser, Marcus; Uhlhaas, Peter J

    2016-01-01

    The graph theoretical analysis of structural magnetic resonance imaging (MRI) data has received a great deal of interest in recent years to characterize the organizational principles of brain networks and their alterations in psychiatric disorders, such as schizophrenia. However, the characterization of networks in clinical populations can be challenging, since the comparison of connectivity between groups is influenced by several factors, such as the overall number of connections and the structural abnormalities of the seed regions. To overcome these limitations, the current study employed the whole-brain analysis of connectional fingerprints in diffusion tensor imaging data obtained at 3 T of chronic schizophrenia patients (n = 16) and healthy, age-matched control participants (n = 17). Probabilistic tractography was performed to quantify the connectivity of 110 brain areas. The connectional fingerprint of a brain area represents the set of relative connection probabilities to all its target areas and is, hence, less affected by overall white and gray matter changes than absolute connectivity measures. After detecting brain regions with abnormal connectional fingerprints through similarity measures, we tested each of its relative connection probability between groups. We found altered connectional fingerprints in schizophrenia patients consistent with a dysconnectivity syndrome. While the medial frontal gyrus showed only reduced connectivity, the connectional fingerprints of the inferior frontal gyrus and the putamen mainly contained relatively increased connection probabilities to areas in the frontal, limbic, and subcortical areas. These findings are in line with previous studies that reported abnormalities in striatal-frontal circuits in the pathophysiology of schizophrenia, highlighting the potential utility of connectional fingerprints for the analysis of anatomical networks in the disorder. PMID:27445870

  17. Abnormal Connectional Fingerprint in Schizophrenia: A Novel Network Analysis of Diffusion Tensor Imaging Data

    PubMed Central

    Edwin Thanarajah, Sharmili; Han, Cheol E.; Rotarska-Jagiela, Anna; Singer, Wolf; Deichmann, Ralf; Maurer, Konrad; Kaiser, Marcus; Uhlhaas, Peter J.

    2016-01-01

    The graph theoretical analysis of structural magnetic resonance imaging (MRI) data has received a great deal of interest in recent years to characterize the organizational principles of brain networks and their alterations in psychiatric disorders, such as schizophrenia. However, the characterization of networks in clinical populations can be challenging, since the comparison of connectivity between groups is influenced by several factors, such as the overall number of connections and the structural abnormalities of the seed regions. To overcome these limitations, the current study employed the whole-brain analysis of connectional fingerprints in diffusion tensor imaging data obtained at 3 T of chronic schizophrenia patients (n = 16) and healthy, age-matched control participants (n = 17). Probabilistic tractography was performed to quantify the connectivity of 110 brain areas. The connectional fingerprint of a brain area represents the set of relative connection probabilities to all its target areas and is, hence, less affected by overall white and gray matter changes than absolute connectivity measures. After detecting brain regions with abnormal connectional fingerprints through similarity measures, we tested each of its relative connection probability between groups. We found altered connectional fingerprints in schizophrenia patients consistent with a dysconnectivity syndrome. While the medial frontal gyrus showed only reduced connectivity, the connectional fingerprints of the inferior frontal gyrus and the putamen mainly contained relatively increased connection probabilities to areas in the frontal, limbic, and subcortical areas. These findings are in line with previous studies that reported abnormalities in striatal–frontal circuits in the pathophysiology of schizophrenia, highlighting the potential utility of connectional fingerprints for the analysis of anatomical networks in the disorder. PMID:27445870

  18. Abnormal Magnetic Field Effects on Electrogenerated Chemiluminescence

    NASA Astrophysics Data System (ADS)

    Pan, Haiping; Shen, Yan; Wang, Hongfeng; He, Lei; Hu, Bin

    2015-03-01

    We report abnormal magnetic field effects on electrogenerated chemiluminescence (MFEECL) based on triplet emission from the Ru(bpy)3Cl2-TPrA electrochemical system: the appearance of MFEECL after magnetic field ceases. In early studies the normal MFEECL have been observed from electrochemical systems during the application of magnetic field. Here, the abnormal MFEECL suggest that the activated charge-transfer [Ru(bpy)33+ … TPrA•] complexes may become magnetized in magnetic field and experience a long magnetic relaxation after removing magnetic field. Our analysis indicates that the magnetic relaxation can gradually increase the density of charge-transfer complexes within reaction region due to decayed magnetic interactions, leading to a positive component in the abnormal MFEECL. On the other hand, the magnetic relaxation facilitates an inverse conversion from triplets to singlets within charge-transfer complexes. The inverse triplet --> singlet conversion reduces the density of triplet light-emitting states through charge-transfer complexes and gives rise to a negative component in the abnormal MFEECL. The combination of positive and negative components can essentially lead to a non-monotonic profile in the abnormal MFEECL after ceasing magnetic field. Nevertheless, our experimental studies may reveal un-usual magnetic behaviors with long magnetic relaxation from the activated charge-transfer [Ru(bpy)33+ … TPrA•] complexes in solution at room temperature.

  19. Abnormal magnetic field effects on electrogenerated chemiluminescence.

    PubMed

    Pan, Haiping; Shen, Yan; Wang, Hongfeng; He, Lei; Hu, Bin

    2015-01-01

    We report abnormal magnetic field effects on electrogenerated chemiluminescence (MFEECL) based on triplet emission from the Ru(bpy)3Cl2-TPrA electrochemical system: the appearance of MFEECL after magnetic field ceases. In early studies the normal MFEECL have been observed from electrochemical systems during the application of magnetic field. Here, the abnormal MFEECL suggest that the activated charge-transfer [Ru(bpy)3(3+) … TPrA(•)] complexes may become magnetized in magnetic field and experience a long magnetic relaxation after removing magnetic field. Our analysis indicates that the magnetic relaxation can gradually increase the density of charge-transfer complexes within reaction region due to decayed magnetic interactions, leading to a positive component in the abnormal MFEECL. On the other hand, the magnetic relaxation facilitates an inverse conversion from triplets to singlets within charge-transfer complexes. The inverse triplet → singlet conversion reduces the density of triplet light-emitting states through charge-transfer complexes and gives rise to a negative component in the abnormal MFEECL. The combination of positive and negative components can essentially lead to a non-monotonic profile in the abnormal MFEECL after ceasing magnetic field. Nevertheless, our experimental studies may reveal un-usual magnetic behaviors with long magnetic relaxation from the activated charge-transfer [Ru(bpy)3(3+) … TPrA(•)] complexes in solution at room temperature. PMID:25772580

  20. Abnormal Magnetic Field Effects on Electrogenerated Chemiluminescence

    PubMed Central

    Pan, Haiping; Shen, Yan; Wang, Hongfeng; He, Lei; Hu, Bin

    2015-01-01

    We report abnormal magnetic field effects on electrogenerated chemiluminescence (MFEECL) based on triplet emission from the Ru(bpy)3Cl2-TPrA electrochemical system: the appearance of MFEECL after magnetic field ceases. In early studies the normal MFEECL have been observed from electrochemical systems during the application of magnetic field. Here, the abnormal MFEECL suggest that the activated charge-transfer [Ru(bpy)33+ … TPrA•] complexes may become magnetized in magnetic field and experience a long magnetic relaxation after removing magnetic field. Our analysis indicates that the magnetic relaxation can gradually increase the density of charge-transfer complexes within reaction region due to decayed magnetic interactions, leading to a positive component in the abnormal MFEECL. On the other hand, the magnetic relaxation facilitates an inverse conversion from triplets to singlets within charge-transfer complexes. The inverse triplet → singlet conversion reduces the density of triplet light-emitting states through charge-transfer complexes and gives rise to a negative component in the abnormal MFEECL. The combination of positive and negative components can essentially lead to a non-monotonic profile in the abnormal MFEECL after ceasing magnetic field. Nevertheless, our experimental studies may reveal un-usual magnetic behaviors with long magnetic relaxation from the activated charge-transfer [Ru(bpy)33+ … TPrA•] complexes in solution at room temperature. PMID:25772580

  1. Abnormal prefrontal cortex resting state functional connectivity and severity of internet gaming disorder.

    PubMed

    Jin, Chenwang; Zhang, Ting; Cai, Chenxi; Bi, Yanzhi; Li, Yangding; Yu, Dahua; Zhang, Ming; Yuan, Kai

    2016-09-01

    Internet Gaming Disorder (IGD) among adolescents has become an important public concern and gained more and more attention internationally. Recent studies focused on IGD and revealed brain abnormalities in the IGD group, especially the prefrontal cortex (PFC). However, the role of PFC-striatal circuits in pathology of IGD remains unknown. Twenty-five adolescents with IGD and 21 age- and gender-matched healthy controls were recruited in our study. Voxel-based morphometric (VBM) and functional connectivity analysis were employed to investigate the abnormal structural and resting-state properties of several frontal regions in individuals with online gaming addiction. Relative to healthy comparison subjects, IGD subjects showed significant decreased gray matter volume in PFC regions including the bilateral dorsolateral prefrontal cortex (DLPFC), orbitofrontal cortex (OFC), anterior cingulate cortex (ACC) and the right supplementary motor area (SMA) after controlling for age and gender effects. We chose these regions as the seeding areas for the resting-state analysis and found that IGD subjects showed decreased functional connectivity between several cortical regions and our seeds, including the insula, and temporal and occipital cortices. Moreover, significant decreased functional connectivity between some important subcortical regions, i.e., dorsal striatum, pallidum, and thalamus, and our seeds were found in the IGD group and some of those changes were associated with the severity of IGD. Our results revealed the involvement of several PFC regions and related PFC-striatal circuits in the process of IGD and suggested IGD may share similar neural mechanisms with substance dependence at the circuit level. PMID:26311395

  2. Abnormal structural connectivity in the brain networks of children with hydrocephalus

    PubMed Central

    Yuan, Weihong; Holland, Scott K.; Shimony, Joshua S.; Altaye, Mekibib; Mangano, Francesco T.; Limbrick, David D.; Jones, Blaise V.; Nash, Tiffany; Rajagopal, Akila; Simpson, Sarah; Ragan, Dustin; McKinstry, Robert C.

    2015-01-01

    Increased intracranial pressure and ventriculomegaly in children with hydrocephalus are known to have adverse effects on white matter structure. This study seeks to investigate the impact of hydrocephalus on topological features of brain networks in children. The goal was to investigate structural network connectivity, at both global and regional levels, in the brains in children with hydrocephalus using graph theory analysis and diffusion tensor tractography. Three groups of children were included in the study (29 normally developing controls, 9 preoperative hydrocephalus patients, and 17 postoperative hydrocephalus patients). Graph theory analysis was applied to calculate the global network measures including small-worldness, normalized clustering coefficients, normalized characteristic path length, global efficiency, and modularity. Abnormalities in regional network parameters, including nodal degree, local efficiency, clustering coefficient, and betweenness centrality, were also compared between the two patients groups (separately) and the controls using two tailed t-test at significance level of p < 0.05 (corrected for multiple comparison). Children with hydrocephalus in both the preoperative and postoperative groups were found to have significantly lower small-worldness and lower normalized clustering coefficient than controls. Children with hydrocephalus in the postoperative group were also found to have significantly lower normalized characteristic path length and lower modularity. At regional level, significant group differences (or differences at trend level) in regional network measures were found between hydrocephalus patients and the controls in a series of brain regions including the medial occipital gyrus, medial frontal gyrus, thalamus, cingulate gyrus, lingual gyrus, rectal gyrus, caudate, cuneus, and insular. Our data showed that structural connectivity analysis using graph theory and diffusion tensor tractography is sensitive to detect

  3. Abnormal structural connectivity in the brain networks of children with hydrocephalus.

    PubMed

    Yuan, Weihong; Holland, Scott K; Shimony, Joshua S; Altaye, Mekibib; Mangano, Francesco T; Limbrick, David D; Jones, Blaise V; Nash, Tiffany; Rajagopal, Akila; Simpson, Sarah; Ragan, Dustin; McKinstry, Robert C

    2015-01-01

    Increased intracranial pressure and ventriculomegaly in children with hydrocephalus are known to have adverse effects on white matter structure. This study seeks to investigate the impact of hydrocephalus on topological features of brain networks in children. The goal was to investigate structural network connectivity, at both global and regional levels, in the brains in children with hydrocephalus using graph theory analysis and diffusion tensor tractography. Three groups of children were included in the study (29 normally developing controls, 9 preoperative hydrocephalus patients, and 17 postoperative hydrocephalus patients). Graph theory analysis was applied to calculate the global network measures including small-worldness, normalized clustering coefficients, normalized characteristic path length, global efficiency, and modularity. Abnormalities in regional network parameters, including nodal degree, local efficiency, clustering coefficient, and betweenness centrality, were also compared between the two patients groups (separately) and the controls using two tailed t-test at significance level of p < 0.05 (corrected for multiple comparison). Children with hydrocephalus in both the preoperative and postoperative groups were found to have significantly lower small-worldness and lower normalized clustering coefficient than controls. Children with hydrocephalus in the postoperative group were also found to have significantly lower normalized characteristic path length and lower modularity. At regional level, significant group differences (or differences at trend level) in regional network measures were found between hydrocephalus patients and the controls in a series of brain regions including the medial occipital gyrus, medial frontal gyrus, thalamus, cingulate gyrus, lingual gyrus, rectal gyrus, caudate, cuneus, and insular. Our data showed that structural connectivity analysis using graph theory and diffusion tensor tractography is sensitive to detect

  4. Abnormally Malicious Autonomous Systems and their Internet Connectivity

    SciTech Connect

    Shue, Craig A; Kalafut, Prof. Andrew; Gupta, Prof. Minaxi

    2011-01-01

    While many attacks are distributed across botnets, investigators and network operators have recently targeted malicious networks through high profile autonomous system (AS) de-peerings and network shut-downs. In this paper, we explore whether some ASes indeed are safe havens for malicious activity. We look for ISPs and ASes that exhibit disproportionately high malicious behavior using ten popular blacklists, plus local spam data, and extensive DNS resolutions based on the contents of the blacklists. We find that some ASes have over 80% of their routable IP address space blacklisted. Yet others account for large fractions of blacklisted IP addresses. Several ASes regularly peer with ASes associated with significant malicious activity. We also find that malicious ASes as a whole differ from benign ones in other properties not obviously related to their malicious activities, such as more frequent connectivity changes with their BGP peers. Overall, we conclude that examining malicious activity at AS granularity can unearth networks with lax security or those that harbor cybercrime.

  5. Gray Matter Abnormalities in Temporal Lobe Epilepsy: Relationships with Resting-State Functional Connectivity and Episodic Memory Performance

    PubMed Central

    Doucet, Gaelle E.; He, Xiaosong; Sperling, Michael; Sharan, Ashwini; Tracy, Joseph I.

    2016-01-01

    Temporal lobe epilepsy (TLE) affects multiple brain regions through evidence from both structural (gray matter; GM) and functional connectivity (FC) studies. We tested whether these structural abnormalities were associated with FC abnormalities, and assessed the ability of these measures to explain episodic memory impairments in this population. A resting-state and T1 sequences were acquired on 94 (45 with mesial temporal pathology) TLE patients and 50 controls, using magnetic resonance imaging (MRI) technique. A voxel-based morphometry analysis was computed to determine the GM volume differences between groups (right, left TLE, controls). Resting-state FC between the abnormal GM volume regions was computed, and compared between groups. Finally, we investigated the relation between EM, GM and FC findings. Patients with and without temporal pathology were analyzed separately. The results revealed reduced GM volume in multiple regions in the patients relative to the controls. Using FC, we found the abnormal GM regions did not display abnormal functional connectivity. Lastly, we found in left TLE patients, verbal episodic memory was associated with abnormal left posterior hippocampus volume, while in right TLE, non-verbal episodic memory was better predicted by resting-state FC measures. This study investigated TLE abnormalities using a multi-modal approach combining GM, FC and neurocognitive measures. We did not find that the GM abnormalities were functionally or abnormally connected during an inter-ictal resting state, which may reflect a weak sensitivity of functional connectivity to the epileptic network. We provided evidence that verbal and non-verbal episodic memory in left and right TLE patients may have distinct relationships with structural and functional measures. Lastly, we provide data suggesting that in the setting of occult, non-lesional right TLE pathology, a coupling of structural and functional abnormalities in extra-temporal/non-ictal regions is

  6. Gray Matter Abnormalities in Temporal Lobe Epilepsy: Relationships with Resting-State Functional Connectivity and Episodic Memory Performance.

    PubMed

    Doucet, Gaelle E; He, Xiaosong; Sperling, Michael; Sharan, Ashwini; Tracy, Joseph I

    2016-01-01

    Temporal lobe epilepsy (TLE) affects multiple brain regions through evidence from both structural (gray matter; GM) and functional connectivity (FC) studies. We tested whether these structural abnormalities were associated with FC abnormalities, and assessed the ability of these measures to explain episodic memory impairments in this population. A resting-state and T1 sequences were acquired on 94 (45 with mesial temporal pathology) TLE patients and 50 controls, using magnetic resonance imaging (MRI) technique. A voxel-based morphometry analysis was computed to determine the GM volume differences between groups (right, left TLE, controls). Resting-state FC between the abnormal GM volume regions was computed, and compared between groups. Finally, we investigated the relation between EM, GM and FC findings. Patients with and without temporal pathology were analyzed separately. The results revealed reduced GM volume in multiple regions in the patients relative to the controls. Using FC, we found the abnormal GM regions did not display abnormal functional connectivity. Lastly, we found in left TLE patients, verbal episodic memory was associated with abnormal left posterior hippocampus volume, while in right TLE, non-verbal episodic memory was better predicted by resting-state FC measures. This study investigated TLE abnormalities using a multi-modal approach combining GM, FC and neurocognitive measures. We did not find that the GM abnormalities were functionally or abnormally connected during an inter-ictal resting state, which may reflect a weak sensitivity of functional connectivity to the epileptic network. We provided evidence that verbal and non-verbal episodic memory in left and right TLE patients may have distinct relationships with structural and functional measures. Lastly, we provide data suggesting that in the setting of occult, non-lesional right TLE pathology, a coupling of structural and functional abnormalities in extra-temporal/non-ictal regions is

  7. Somatosensory cortex functional connectivity abnormalities in autism show opposite trends, depending on direction and spatial scale

    PubMed Central

    Khan, Sheraz; Michmizos, Konstantinos; Tommerdahl, Mark; Ganesan, Santosh; Kitzbichler, Manfred G.; Zetino, Manuel; Garel, Keri-Lee A.; Herbert, Martha R.; Hämäläinen, Matti S.

    2015-01-01

    Functional connectivity is abnormal in autism, but the nature of these abnormalities remains elusive. Different studies, mostly using functional magnetic resonance imaging, have found increased, decreased, or even mixed pattern functional connectivity abnormalities in autism, but no unifying framework has emerged to date. We measured functional connectivity in individuals with autism and in controls using magnetoencephalography, which allowed us to resolve both the directionality (feedforward versus feedback) and spatial scale (local or long-range) of functional connectivity. Specifically, we measured the cortical response and functional connectivity during a passive 25-Hz vibrotactile stimulation in the somatosensory cortex of 20 typically developing individuals and 15 individuals with autism, all males and right-handed, aged 8–18, and the mu-rhythm during resting state in a subset of these participants (12 per group, same age range). Two major significant group differences emerged in the response to the vibrotactile stimulus. First, the 50-Hz phase locking component of the cortical response, generated locally in the primary (S1) and secondary (S2) somatosensory cortex, was reduced in the autism group (P < 0.003, corrected). Second, feedforward functional connectivity between S1 and S2 was increased in the autism group (P < 0.004, corrected). During resting state, there was no group difference in the mu-α rhythm. In contrast, the mu-β rhythm, which has been associated with feedback connectivity, was significantly reduced in the autism group (P < 0.04, corrected). Furthermore, the strength of the mu-β was correlated to the relative strength of 50 Hz component of the response to the vibrotactile stimulus (r = 0.78, P < 0.00005), indicating a shared aetiology for these seemingly unrelated abnormalities. These magnetoencephalography-derived measures were correlated with two different behavioural sensory processing scores (P < 0.01 and P < 0.02 for the autism

  8. Abnormal interhemispheric resting state functional connectivity of the insula in heroin users under methadone maintenance treatment.

    PubMed

    Wang, Peng-Wei; Lin, Huang-Chi; Liu, Gin-Chung; Yang, Yi-Hsin Connie; Ko, Chih-Hung; Yen, Cheng-Fang

    2016-09-30

    Abnormal interhemispheric functional connectivity is attracting more and more attention in the field of substance use. This study aimed to examine 1) the differences in interhemispheric functional connections of the insula with the contralateral insula and other brain regions between heroin users under methadone maintenance treatment (MMT) and healthy controls, and 2) the association between heroin users' interhemispheric insular functional connectivity using resting functional magnetic resonance imaging (fMRI) and the results of urine heroin analysis. Sixty male right-handed persons, including 30 with heroin dependence under MMT and 30 healthy controls, were recruited to this study. Resting fMRI experiments and urine heroin analysis were performed. Compared with the controls, the heroin users had a significantly lower interhemispheric insular functional connectivity. They also exhibited lower functional connectivity between insula and contralateral inferior orbital frontal lobe. After controlling for age, educational level and methadone dosage, less deviation of the interhemispheric insula functional connectivity was significantly associated with a lower risk of a positive urine heroin analysis result. Our findings demonstrated that the heroin users under MMT had abnormal long-range and interhemispheric resting functional connections. Those with a less dysfunctional interhemispheric insula functional connectivity had a lower risk of a positive urine heroin test. PMID:27497215

  9. Dissociable cortico-striatal connectivity abnormalities in major depression in response to monetary gains and penalties

    PubMed Central

    Admon, Roee; Nickerson, Lisa D.; Dillon, Daniel G.; Holmes, Avram J.; Bogdan, Ryan; Kumar, Poornima; Dougherty, Darin D.; Iosifescu, Dan V.; Mischoulon, David; Fava, Maurizio; Pizzagalli, Diego A.

    2014-01-01

    Background Individuals with major depressive disorder (MDD) are characterized by maladaptive responses to both positive and negative outcomes, which have been linked to localized abnormal activations in cortical and striatal brain regions. However, the exact neural circuitry implicated in such abnormalities remains largely unexplored. Methods In this study 26 unmedicated adults with MDD and 29 matched healthy controls completed a monetary incentive delay task during functional magnetic resonance imaging (fMRI). Psycho-physiological interaction (PPI) analyses probed group differences in connectivity separately in response to positive and negative outcomes (i.e., monetary gains and penalties). Results Relative to controls, MDD subjects displayed decreased connectivity between the caudate and dorsal anterior cingulate cortex (dACC) in response to monetary gains, yet increased connectivity between the caudate and a different, more rostral, dACC sub-region in response to monetary penalties. Moreover, exploratory analyses of 14 MDD patients who completed a 12-week, double-blind, placebo-controlled clinical trial after the baseline fMRI scans indicated that a more normative pattern of cortico-striatal connectivity pre-treatment was associated with more symptoms improvement 12 weeks later. Conclusions These results identify the caudate as a region with dissociable incentive-dependent dACC connectivity abnormalities in MDD, and provide initial evidence that cortico-striatal circuitry may play a role in MDD treatment response. Given the role of cortico-striatal circuitry in encoding action-outcome contingencies, such dysregulated connectivity may relate to the prominent disruptions in goal-directed behavior that characterize MDD. PMID:25055809

  10. Abnormal Anatomical Connectivity between the Amygdala and Orbitofrontal Cortex in Conduct Disorder

    PubMed Central

    Passamonti, Luca; Fairchild, Graeme; Fornito, Alex; Goodyer, Ian M.; Nimmo-Smith, Ian; Hagan, Cindy C.; Calder, Andrew J.

    2012-01-01

    Objective Previous research suggested that structural and functional abnormalities within the amygdala and orbitofrontal cortex contribute to the pathophysiology of Conduct Disorder (CD). Here, we investigated whether the integrity of the white-matter pathways connecting these regions is abnormal and thus may represent a putative neurobiological marker for CD. Methods Diffusion Tensor Imaging (DTI) was used to investigate white-matter microstructural integrity in male adolescents with childhood-onset CD, compared with healthy controls matched in age, sex, intelligence, and socioeconomic status. Two approaches were employed to analyze DTI data: voxel-based morphometry of fractional anisotropy (FA), an index of white-matter integrity, and virtual dissection of white-matter pathways using tractography. Results Adolescents with CD displayed higher FA within the right external capsule relative to controls (T = 6.08, P<0.05, Family-Wise Error, whole-brain correction). Tractography analyses showed that FA values within the uncinate fascicle (connecting the amygdala and orbitofrontal cortex) were abnormally increased in individuals with CD relative to controls. This was in contrast with the inferior frontal-occipital fascicle, which showed no significant group differences in FA. The finding of increased FA in the uncinate fascicle remained significant when factoring out the contribution of attention-deficit/hyperactivity disorder symptoms. There were no group differences in the number of streamlines in either of these anatomical tracts. Conclusions These results provide evidence that CD is associated with white-matter microstructural abnormalities in the anatomical tract that connects the amygdala and orbitofrontal cortex, the uncinate fascicle. These results implicate abnormal maturation of white-matter pathways which are fundamental in the regulation of emotional behavior in CD. PMID:23144970

  11. The abnormal electrostatic discharge of a no-connect metal cover in a ceramic packaging device

    NASA Astrophysics Data System (ADS)

    Song, Li; Chuanbin, Zeng; Jiajun, Luo; Zhengsheng, Han

    2013-08-01

    The human body model (HBM) stress of a no-connect metal cover is tested to obtain the characteristics of abnormal electrostatic discharge, including current waveforms and peak current under varied stress voltage and device failure voltage. A new discharge model called the "sparkover-induced model" is proposed based on the results. Then, failure mechanism analysis and model simulation are performed to prove that the transient peak current caused by a sparkover of low arc impedance will result in the devices' premature damage when the potential difference between the no-connect metal cover and the chip exceeds the threshold voltage of sparkover.

  12. A small number of abnormal brain connections predicts adult autism spectrum disorder

    PubMed Central

    Yahata, Noriaki; Morimoto, Jun; Hashimoto, Ryuichiro; Lisi, Giuseppe; Shibata, Kazuhisa; Kawakubo, Yuki; Kuwabara, Hitoshi; Kuroda, Miho; Yamada, Takashi; Megumi, Fukuda; Imamizu, Hiroshi; Náñez Sr, José E.; Takahashi, Hidehiko; Okamoto, Yasumasa; Kasai, Kiyoto; Kato, Nobumasa; Sasaki, Yuka; Watanabe, Takeo; Kawato, Mitsuo

    2016-01-01

    Although autism spectrum disorder (ASD) is a serious lifelong condition, its underlying neural mechanism remains unclear. Recently, neuroimaging-based classifiers for ASD and typically developed (TD) individuals were developed to identify the abnormality of functional connections (FCs). Due to over-fitting and interferential effects of varying measurement conditions and demographic distributions, no classifiers have been strictly validated for independent cohorts. Here we overcome these difficulties by developing a novel machine-learning algorithm that identifies a small number of FCs that separates ASD versus TD. The classifier achieves high accuracy for a Japanese discovery cohort and demonstrates a remarkable degree of generalization for two independent validation cohorts in the USA and Japan. The developed ASD classifier does not distinguish individuals with major depressive disorder and attention-deficit hyperactivity disorder from their controls but moderately distinguishes patients with schizophrenia from their controls. The results leave open the viable possibility of exploring neuroimaging-based dimensions quantifying the multiple-disorder spectrum. PMID:27075704

  13. A small number of abnormal brain connections predicts adult autism spectrum disorder.

    PubMed

    Yahata, Noriaki; Morimoto, Jun; Hashimoto, Ryuichiro; Lisi, Giuseppe; Shibata, Kazuhisa; Kawakubo, Yuki; Kuwabara, Hitoshi; Kuroda, Miho; Yamada, Takashi; Megumi, Fukuda; Imamizu, Hiroshi; Náñez, José E; Takahashi, Hidehiko; Okamoto, Yasumasa; Kasai, Kiyoto; Kato, Nobumasa; Sasaki, Yuka; Watanabe, Takeo; Kawato, Mitsuo

    2016-01-01

    Although autism spectrum disorder (ASD) is a serious lifelong condition, its underlying neural mechanism remains unclear. Recently, neuroimaging-based classifiers for ASD and typically developed (TD) individuals were developed to identify the abnormality of functional connections (FCs). Due to over-fitting and interferential effects of varying measurement conditions and demographic distributions, no classifiers have been strictly validated for independent cohorts. Here we overcome these difficulties by developing a novel machine-learning algorithm that identifies a small number of FCs that separates ASD versus TD. The classifier achieves high accuracy for a Japanese discovery cohort and demonstrates a remarkable degree of generalization for two independent validation cohorts in the USA and Japan. The developed ASD classifier does not distinguish individuals with major depressive disorder and attention-deficit hyperactivity disorder from their controls but moderately distinguishes patients with schizophrenia from their controls. The results leave open the viable possibility of exploring neuroimaging-based dimensions quantifying the multiple-disorder spectrum. PMID:27075704

  14. Abnormal striatal resting-state functional connectivity in adolescents with obsessive-compulsive disorder.

    PubMed

    Bernstein, Gail A; Mueller, Bryon A; Schreiner, Melinda Westlund; Campbell, Sarah M; Regan, Emily K; Nelson, Peter M; Houri, Alaa K; Lee, Susanne S; Zagoloff, Alexandra D; Lim, Kelvin O; Yacoub, Essa S; Cullen, Kathryn R

    2016-01-30

    Neuroimaging research has implicated abnormalities in cortico-striatal-thalamic-cortical (CSTC) circuitry in pediatric obsessive-compulsive disorder (OCD). In this study, resting-state functional magnetic resonance imaging (R-fMRI) was used to investigate functional connectivity in the CSTC circuitry in adolescents with OCD. Imaging was obtained with the Human Connectome Project (HCP) scanner using newly developed pulse sequences which allow for higher spatial and temporal resolution. Fifteen adolescents with OCD and 13 age- and gender-matched healthy controls (ages 12-19) underwent R-fMRI on the 3T HCP scanner. Twenty-four minutes of resting-state scans (two consecutive 12-min scans) were acquired. We investigated functional connectivity of the striatum using a seed-based, whole brain approach with anatomically-defined seeds placed in the bilateral caudate, putamen, and nucleus accumbens. Adolescents with OCD compared with controls exhibited significantly lower functional connectivity between the left putamen and a single cluster of right-sided cortical areas including parts of the orbitofrontal cortex, inferior frontal gyrus, insula, and operculum. Preliminary findings suggest that impaired striatal connectivity in adolescents with OCD in part falls within the predicted CSTC network, and also involves impaired connections between a key CSTC network region (i.e., putamen) and key regions in the salience network (i.e., insula/operculum). The relevance of impaired putamen-insula/operculum connectivity in OCD is discussed. PMID:26674413

  15. Resting state functional MRI reveals abnormal network connectivity in neurofibromatosis 1.

    PubMed

    Tomson, Steffie N; Schreiner, Matthew J; Narayan, Manjari; Rosser, Tena; Enrique, Nicole; Silva, Alcino J; Allen, Genevera I; Bookheimer, Susan Y; Bearden, Carrie E

    2015-11-01

    Neurofibromatosis type I (NF1) is a genetic disorder caused by mutations in the neurofibromin 1 gene at locus 17q11.2. Individuals with NF1 have an increased incidence of learning disabilities, attention deficits, and autism spectrum disorders. As a single-gene disorder, NF1 represents a valuable model for understanding gene-brain-behavior relationships. While mouse models have elucidated molecular and cellular mechanisms underlying learning deficits associated with this mutation, little is known about functional brain architecture in human subjects with NF1. To address this question, we used resting state functional connectivity magnetic resonance imaging (rs-fcMRI) to elucidate the intrinsic network structure of 30 NF1 participants compared with 30 healthy demographically matched controls during an eyes-open rs-fcMRI scan. Novel statistical methods were employed to quantify differences in local connectivity (edge strength) and modularity structure, in combination with traditional global graph theory applications. Our findings suggest that individuals with NF1 have reduced anterior-posterior connectivity, weaker bilateral edges, and altered modularity clustering relative to healthy controls. Further, edge strength and modular clustering indices were correlated with IQ and internalizing symptoms. These findings suggest that Ras signaling disruption may lead to abnormal functional brain connectivity; further investigation into the functional consequences of these alterations in both humans and in animal models is warranted. PMID:26304096

  16. Abnormalities of hippocampal-cortical connectivity in temporal lobe epilepsy patients with hippocampal sclerosis

    NASA Astrophysics Data System (ADS)

    Li, Wenjing; He, Huiguang; Lu, Jingjing; Wang, Chunheng; Li, Meng; Lv, Bin; Jin, Zhengyu

    2011-03-01

    Hippocampal sclerosis (HS) is the most common damage seen in the patients with temporal lobe epilepsy (TLE). In the present study, the hippocampal-cortical connectivity was defined as the correlation between the hippocampal volume and cortical thickness at each vertex throughout the whole brain. We aimed to investigate the differences of ipsilateral hippocampal-cortical connectivity between the unilateral TLE-HS patients and the normal controls. In our study, the bilateral hippocampal volumes were first measured in each subject, and we found that the ipsilateral hippocampal volume significantly decreased in the left TLE-HS patients. Then, group analysis showed significant thinner average cortical thickness of the whole brain in the left TLE-HS patients compared with the normal controls. We found significantly increased ipsilateral hippocampal-cortical connectivity in the bilateral superior temporal gyrus, the right cingulate gyrus and the left parahippocampal gyrus of the left TLE-HS patients, which indicated structural vulnerability related to the hippocampus atrophy in the patient group. However, for the right TLE-HS patients, no significant differences were found between the patients and the normal controls, regardless of the ipsilateral hippocampal volume, the average cortical thickness or the patterns of hippocampal-cortical connectivity, which might be related to less atrophies observed in the MRI scans. Our study provided more evidence for the structural abnormalities in the unilateral TLE-HS patients.

  17. Dorsal Striatum and Its Limbic Connectivity Mediate Abnormal Anticipatory Reward Processing in Obesity

    PubMed Central

    Nummenmaa, Lauri; Hirvonen, Jussi; Hannukainen, Jarna C.; Immonen, Heidi; Lindroos, Markus M.; Salminen, Paulina; Nuutila, Pirjo

    2012-01-01

    Obesity is characterized by an imbalance in the brain circuits promoting reward seeking and those governing cognitive control. Here we show that the dorsal caudate nucleus and its connections with amygdala, insula and prefrontal cortex contribute to abnormal reward processing in obesity. We measured regional brain glucose uptake in morbidly obese (n = 19) and normal weighted (n = 16) subjects with 2-[18F]fluoro-2-deoxyglucose ([18F]FDG) positron emission tomography (PET) during euglycemic hyperinsulinemia and with functional magnetic resonance imaging (fMRI) while anticipatory food reward was induced by repeated presentations of appetizing and bland food pictures. First, we found that glucose uptake rate in the dorsal caudate nucleus was higher in obese than in normal-weight subjects. Second, obese subjects showed increased hemodynamic responses in the caudate nucleus while viewing appetizing versus bland foods in fMRI. The caudate also showed elevated task-related functional connectivity with amygdala and insula in the obese versus normal-weight subjects. Finally, obese subjects had smaller responses to appetizing versus bland foods in the dorsolateral and orbitofrontal cortices than did normal-weight subjects, and failure to activate the dorsolateral prefrontal cortex was correlated with high glucose metabolism in the dorsal caudate nucleus. These findings suggest that enhanced sensitivity to external food cues in obesity may involve abnormal stimulus-response learning and incentive motivation subserved by the dorsal caudate nucleus, which in turn may be due to abnormally high input from the amygdala and insula and dysfunctional inhibitory control by the frontal cortical regions. These functional changes in the responsiveness and interconnectivity of the reward circuit could be a critical mechanism to explain overeating in obesity. PMID:22319604

  18. Abnormal Functional Connectivity of Amygdala in Late-Onset Depression Was Associated with Cognitive Deficits

    PubMed Central

    Yue, Yingying; Yuan, Yonggui; Hou, Zhenghua; Jiang, Wenhao; Bai, Feng; Zhang, Zhijun

    2013-01-01

    Background Major depressive disorder (MDD) is associated with decreased function of cortico-limbic circuits, which play important roles in the pathogenesis of MDD. Abnormal functional connectivity (FC) with the amygdala, which is involved in cortico-limbic circuits, has also been observed in MDD. However, little is known about connectivity alterations in late-onset depression (LOD) or whether disrupted connectivity is correlated with cognitive impairment in LOD. Methods and Results A total of twenty-two LOD patients and twenty-two matched healthy controls (HC) underwent neuropsychological tests and resting state functional magnetic resonance imaging (rs-fMRI). Regional homogeneity (ReHo) and FC with bilateral amygdala seeds were used to analyze blood oxygen level-dependent fMRI data between two groups. Compared with HC, LOD patients showed decreased ReHo in the right middle frontal gyrus and left superior frontal gyrus. In the LOD group, the left amygdala had decreased FC with the right middle frontal gyrus and the left superior frontal gyrus in the amygdala positive network, and it had increased FC with the right post-central gyrus in the amygdala negative network. However, significantly reduced FC with the right amygdala was observed in the right middle occipital gyrus in the amygdala negative network. Further correlative analyses revealed that decreased FC between the amygdala and the right middle occipital gyrus was negatively correlated with the verbal fluency test (VFT, r = −0.485, P = 0.022) and the digit span test (DST, r = −0.561, P = 0.007). Conclusions Our findings of reduced activity of the prefrontal gyrus and abnormal FC with the bilateral amygdala may be key markers of cognitive dysfunction in LOD patients. PMID:24040385

  19. Global functional connectivity abnormalities in children with Fetal Alcohol Spectrum Disorders (FASD)

    PubMed Central

    Wozniak, Jeffrey R.; Mueller, Bryon A.; Bell, Christopher J.; Muetzel, Ryan L.; Hoecker, Heather L.; Boys, Christopher J.; Lim, Kelvin O.

    2012-01-01

    Background Previous studies, including those employing Diffusion Tensor Imaging (DTI), have revealed significant disturbances in the white matter of individuals with Fetal Alcohol Spectrum Disorders (FASD). Both macrostructural and microstructural abnormalities have been observed across levels of FASD severity. Emerging evidence suggests that these white matter abnormalities are associated with functional deficits. This study used resting-state fMRI to evaluate the status of network functional connectivity in children with FASD compared to control subjects. Methods Participants included 24 children with FASD, ages 10–17, and 31 matched controls. Neurocognitive tests were administered including Wechsler Intelligence Scales, California Verbal Learning Test, and Behavior Rating Inventory of Executive Functioning. High resolution anatomical MRI data and six-minute resting-state fMRI data were collected. The resting-state fMRI data were subjected to a graph theory analysis and four global measures of cortical network connectivity were computed: characteristic path length, mean clustering coefficient, local efficiency, and global efficiency. Results Results revealed significantly altered network connectivity in those with FASD. The characteristic path length was 3.1% higher (p=.04, Cohen’s d=.47) and global efficiency was 1.9% lower (p=.04, d=.63) in children with FASD compared to controls, suggesting decreased network capacity that may have implications for integrative cognitive functioning. Global efficiency was significantly positively correlated with cortical thickness in frontal (r=.38, p=.005), temporal (r=.28, p=.043), and parietal (r=.36, p=.008) regions. No relationship between facial dysmorphology and functional connectivity was observed. Exploratory correlations suggested that global efficiency and characteristic path length are associated with capacity for immediate verbal memory on the CVLT (r=.41, p=.05 and r=.41, p=.01 respectively) among those with

  20. Hypercatabolism of normal IgG; an unexplained immunoglobulin abnormality in the connective tissue diseases

    PubMed Central

    Wochner, R. Dean

    1970-01-01

    The metabolism of radioiodinated IgG was studied in a series of 42 patients with connective tissue diseases (16 systemic lupus erythematosus, nine rheumatoid arthritis, five polymyositis, five vasculitis, and seven miscellaneous diagnoses). Fractional catabolic rates were increased and survival half-lives were shortened in all diagnostic categories indicating hypercatabolism of IgG. This hypercatabolism was masked by increased IgG synthesis, resulting in elevated serum concentrations of IgG in patients with systemic lupus erythematosus and rheumatoid arthritis and in generally normal concentrations in the others. The metabolism of iodinated IgM was also studied in eight patients with systemic lupus erythematosus, in seven with rheumatoid arthritis, and in 12 controls. The fractional catabolic rates were normal in both groups of patients. Serum concentrations of both IgM and IgA were moderately elevated in all diagnostic categories. Serum albumin metabolism was entirely normal in the nine subjects studied who were not receiving corticosteroids; in three who were receiving them, moderate hypercatabolism was observed. The hypercatabolism of IgG could not be accounted for by factors previously known to alter IgG metabolism. It was not observed in 15 patients with other chronic, inflammatory diseases and was not explained by concomitant administration of adrenal corticosteroids to some patients. Identical results were obtained whether the IgG was obtained from a patient himself or from a normal donor, demonstrating that the hypercatabolism is a host defect and not an abnormality of the protein. Thus, patients with connective tissue disease of several different diagnostic categories have been shown to have an unexplained immunoglobulin abnormality: they catabolize normal IgG at an accelerated rate. PMID:5415673

  1. Modeling the Relationship among Gray Matter Atrophy, Abnormalities in Connecting White Matter, and Cognitive Performance in Early Multiple Sclerosis

    PubMed Central

    Kuceyeski, A.F.; Vargas, W.; Dayan, M.; Monohan, E.; Blackwell, C.; Raj, A.; Fujimoto, K.; Gauthier, S.A.

    2016-01-01

    Background and Purpose Quantitative assessment of clinical and pathologic consequences of white matter abnormalities in multiple sclerosis is critical in understanding the pathways of disease. This study aimed to test whether gray matter atrophy was related to abnormalities in connecting white matter and to identify patterns of imaging biomarker abnormalities that were related to patient processing speed. Materials and Methods Image data and Symbol Digit Modalities Test scores were collected from a cohort of patients with early multiple sclerosis. The Network Modification Tool was used to estimate connectivity irregularities by projecting white matter abnormalities onto connecting gray matter regions. Partial least-squares regression quantified the relationship between imaging biomarkers and processing speed as measured by the Symbol Digit Modalities Test. Results Atrophy in deep gray matter structures of the thalami and putamen had moderate and significant correlations with abnormalities in connecting white matter (r = 0.39–0.41, P < .05 corrected). The 2 models of processing speed, 1 for each of the WM imaging biomarkers, had goodness-of-fit (R2) values of 0.42 and 0.30. A measure of the impact of white matter lesions on the connectivity of occipital and parietal areas had significant nonzero regression coefficients. Conclusions We concluded that deep gray matter regions may be susceptible to inflammation and/or demyelination in white matter, possibly having a higher sensitivity to remote degeneration, and that lesions affecting visual processing pathways were related to processing speed. The Network Modification Tool may be used to quantify the impact of early white matter abnormalities on both connecting gray matter structures and processing speed. PMID:25414004

  2. Abnormal functional global and local brain connectivity in female patients with anorexia nervosa

    PubMed Central

    Geisler, Daniel; Borchardt, Viola; Lord, Anton R.; Boehm, Ilka; Ritschel, Franziska; Zwipp, Johannes; Clas, Sabine; King, Joseph A.; Wolff-Stephan, Silvia; Roessner, Veit; Walter, Martin; Ehrlich, Stefan

    2016-01-01

    Background Previous resting-state functional connectivity studies in patients with anorexia nervosa used independent component analysis or seed-based connectivity analysis to probe specific brain networks. Instead, modelling the entire brain as a complex network allows determination of graph-theoretical metrics, which describe global and local properties of how brain networks are organized and how they interact. Methods To determine differences in network properties between female patients with acute anorexia nervosa and pairwise matched healthy controls, we used resting-state fMRI and computed well-established global and local graph metrics across a range of network densities. Results Our analyses included 35 patients and 35 controls. We found that the global functional network structure in patients with anorexia nervosa is characterized by increases in both characteristic path length (longer average routes between nodes) and assortativity (more nodes with a similar connectedness link together). Accordingly, we found locally decreased connectivity strength and increased path length in the posterior insula and thalamus. Limitations The present results may be limited to the methods applied during preprocessing and network construction. Conclusion We demonstrated anorexia nervosa–related changes in the network configuration for, to our knowledge, the first time using resting-state fMRI and graph-theoretical measures. Our findings revealed an altered global brain network architecture accompanied by local degradations indicating wide-scale disturbance in information flow across brain networks in patients with acute anorexia nervosa. Reduced local network efficiency in the thalamus and posterior insula may reflect a mechanism that helps explain the impaired integration of visuospatial and homeostatic signals in patients with this disorder, which is thought to be linked to abnormal representations of body size and hunger. PMID:26252451

  3. Abnormal resting-state functional connectivity within the default mode network subregions in male patients with obstructive sleep apnea

    PubMed Central

    Li, Hai-Jun; Nie, Xiao; Gong, Hong-Han; Zhang, Wei; Nie, Si; Peng, De-Chang

    2016-01-01

    Background and objective Abnormal resting-state functional connectivity (rs-FC) between the central executive network and the default mode network (DMN) in patients with obstructive sleep apnea (OSA) has been reported. However, the effect of OSA on rs-FC within the DMN subregions remains uncertain. This study was designed to investigate whether the rs-FC within the DMN subregions was disrupted and determine its relationship with clinical symptoms in patients with OSA. Methods Forty male patients newly diagnosed with severe OSA and 40 male education- and age-matched good sleepers (GSs) underwent functional magnetic resonance imaging (fMRI) examinations and clinical and neuropsychologic assessments. Seed-based region of interest rs-FC method was used to analyze the connectivity between each pair of subregions within the DMN, including the medial prefrontal cortex (MPFC), posterior cingulate cortex (PCC), hippocampus formation (HF), inferior parietal cortices (IPC), and medial temporal lobe (MTL). The abnormal rs-FC strength within the DMN subregions was correlated with clinical and neuropsychologic assessments using Pearson correlation analysis in patients with OSA. Results Compared with GSs, patients with OSA had significantly decreased rs-FC between the right HF and the PCC, MPFC, and left MTL. However, patients with OSA had significantly increased rs-FC between the MPFC and left and right IPC, and between the left IPC and right IPC. The rs-FC between the right HF and left MTL was positively correlated with rapid eye movement (r=0.335, P=0.035). The rs-FC between the PCC and right HF was negatively correlated with delayed memory (r=-0.338, P=0.033). Conclusion OSA selectively impairs the rs-FC between right HF and PCC, MPFC, and left MTL within the DMN subregions, and provides an imaging indicator for assessment of cognitive dysfunction in OSA patients. PMID:26855576

  4. Determination of effective brain connectivity from functional connectivity with application to resting state connectivities.

    PubMed

    Robinson, P A; Sarkar, S; Pandejee, Grishma Mehta; Henderson, J A

    2014-07-01

    Neural field theory insights are used to derive effective brain connectivity matrices from the functional connectivity matrix defined by activity covariances. The symmetric case is exactly solved for a resting state system driven by white noise, in which strengths of connections, often termed effective connectivities, are inferred from functional data; these include strengths of connections that are underestimated or not detected by anatomical imaging. Proximity to criticality is calculated and found to be consistent with estimates obtainable from other methods. Links between anatomical, effective, and functional connectivity and resting state activity are quantified, with applicability to other complex networks. Proof-of-principle results are illustrated using published experimental data on anatomical connectivity and resting state functional connectivity. In particular, it is shown that functional connection matrices can be used to uncover the existence and strength of connections that are missed from anatomical connection matrices, including interhemispheric connections that are difficult to track with techniques such as diffusion spectrum imaging. PMID:25122335

  5. Effects of abnormal excitation on the dynamics of spiral waves

    NASA Astrophysics Data System (ADS)

    Min-Yi, Deng; Xue-Liang, Zhang; Jing-Yu, Dai

    2016-01-01

    The effect of physiological and pathological abnormal excitation of a myocyte on the spiral waves is investigated based on the cellular automaton model. When the excitability of the medium is high enough, the physiological abnormal excitation causes the spiral wave to meander irregularly and slowly. When the excitability of the medium is low enough, the physiological abnormal excitation leads to a new stable spiral wave. On the other hand, the pathological abnormal excitation destroys the spiral wave and results in the spatiotemporal chaos, which agrees with the clinical conclusion that the early after depolarization is the pro-arrhythmic mechanism of some anti-arrhythmic drugs. The mechanisms underlying these phenomena are analyzed. Project supported by the National Natural Science Foundation of China (Grant Nos. 11365003 and 11165004).

  6. Abnormal resting-state functional connectivity of the nucleus accumbens in multi-year abstinent heroin addicts.

    PubMed

    Zou, Feng; Wu, Xinhuai; Zhai, Tianye; Lei, Yu; Shao, Yongcong; Jin, Xiao; Tan, Shuwen; Wu, Bing; Wang, Lubin; Yang, Zheng

    2015-11-01

    Functional neuroimaging studies suggest that abnormal brain functional connectivity may be the neural underpinning of addiction to illicit drugs and of relapse after successful cessation therapy. Aberrant brain networks have been demonstrated in addicted patients and in newly abstinent addicts. However, it is not known whether abnormal brain connectivity patterns persist after prolonged abstinence. In this cross-sectional study, whole-brain resting-state functional magnetic resonance images (8 min) were collected from 30 heroin-addicted individuals after a long period of abstinence (more than 3 years) and from 30 healthy controls. We first examined the group differences in the resting-state functional connectivity of the nucleus accumbens (NAc), a brain region implicated in relapse-related processes, including craving and reactivity to stress following acute and protracted withdrawal from heroin. We then examined the relation between the duration of abstinence and the altered NAc functional connectivity in the heroin group. We found that, compared with controls, heroin-dependent participants exhibited significantly greater functional connectivity between the right ventromedial prefrontal cortex and the NAc and weaker functional connectivity between the NAc and the left putamen, left precuneus, and supplementary motor area. However, with longer abstinence time, the strength of NAc functional connectivity with the left putamen increased. These results indicate that dysfunction of the NAc functional network is still present in long-term-abstinent heroin-dependent individuals. PMID:26280556

  7. Abnormalities in large scale functional networks in unmedicated patients with schizophrenia and effects of risperidone

    PubMed Central

    Kraguljac, Nina Vanessa; White, David Matthew; Hadley, Jennifer Ann; Visscher, Kristina; Knight, David; ver Hoef, Lawrence; Falola, Blessing; Lahti, Adrienne Carol

    2015-01-01

    Objective To describe abnormalities in large scale functional networks in unmedicated patients with schizophrenia and to examine effects of risperidone on networks. Material and methods 34 unmedicated patients with schizophrenia and 34 matched healthy controls were enrolled in this longitudinal study. We collected resting state functional MRI data with a 3T scanner at baseline and six weeks after they were started on risperidone. In addition, a group of 19 healthy controls were scanned twice six weeks apart. Four large scale networks, the dorsal attention network, executive control network, salience network, and default mode network were identified with seed based functional connectivity analyses. Group differences in connectivity, as well as changes in connectivity over time, were assessed on the group's participant level functional connectivity maps. Results In unmedicated patients with schizophrenia we found resting state connectivity to be increased in the dorsal attention network, executive control network, and salience network relative to control participants, but not the default mode network. Dysconnectivity was attenuated after six weeks of treatment only in the dorsal attention network. Baseline connectivity in this network was also related to clinical response at six weeks of treatment with risperidone. Conclusions Our results demonstrate abnormalities in large scale functional networks in patients with schizophrenia that are modulated by risperidone only to a certain extent, underscoring the dire need for development of novel antipsychotic medications that have the ability to alleviate symptoms through attenuation of dysconnectivity. PMID:26793436

  8. Cocaine addiction related reproducible brain regions of abnormal default-mode network functional connectivity: a group ICA study with different model orders.

    PubMed

    Ding, Xiaoyu; Lee, Seong-Whan

    2013-08-26

    Model order selection in group independent component analysis (ICA) has a significant effect on the obtained components. This study investigated the reproducible brain regions of abnormal default-mode network (DMN) functional connectivity related with cocaine addiction through different model order settings in group ICA. Resting-state fMRI data from 24 cocaine addicts and 24 healthy controls were temporally concatenated and processed by group ICA using model orders of 10, 20, 30, 40, and 50, respectively. For each model order, the group ICA approach was repeated 100 times using the ICASSO toolbox and after clustering the obtained components, centrotype-based anterior and posterior DMN components were selected for further analysis. Individual DMN components were obtained through back-reconstruction and converted to z-score maps. A whole brain mixed effects factorial ANOVA was performed to explore the differences in resting-state DMN functional connectivity between cocaine addicts and healthy controls. The hippocampus, which showed decreased functional connectivity in cocaine addicts for all the tested model orders, might be considered as a reproducible abnormal region in DMN associated with cocaine addiction. This finding suggests that using group ICA to examine the functional connectivity of the hippocampus in the resting-state DMN may provide an additional insight potentially relevant for cocaine-related diagnoses and treatments. PMID:23707901

  9. Abnormal Functional Connectivity in Children with Attention-Deficit/Hyperactivity Disorder

    PubMed Central

    Tomasi, Dardo; Volkow, Nora D.

    2012-01-01

    Background Attention-deficit/hyperactivity disorder (ADHD) is typically characterized by symptoms of inattention and hyperactivity/impulsivity, but there is increased recognition of a motivation deficit too. This neuropathology may reflect dysfunction of both attention and reward-motivation networks. Methods To test this hypothesis, we compared the functional connectivity density between 247 ADHD and 304 typically developing control children from a public magnetic resonance imaging database. We quantified short- and long-range functional connectivity density in the brain using an ultrafast data-driven approach. Results Children with ADHD had lower connectivity (short- and long-range) in regions of the dorsal attention (superior parietal cortex) and default-mode (precuneus) networks and in cerebellum and higher connectivity (short-range) in reward-motivation regions (ventral striatum and orbitofrontal cortex) than control subjects. In ADHD children, the orbitofrontal cortex (region involved in salience attribution) had higher connectivity with reward-motivation regions (striatum and anterior cingulate) and lower connectivity with superior parietal cortex (region involved in attention processing). Conclusions The enhanced connectivity within reward-motivation regions and their decreased connectivity with regions from the default-mode and dorsal attention networks suggest impaired interactions between control and reward pathways in ADHD that might underlie attention and motivation deficits in ADHD. PMID:22153589

  10. Abnormal resting-state functional connectivity of the left caudate nucleus in obsessive-compulsive disorder.

    PubMed

    Chen, Yunhui; Juhás, Michal; Greenshaw, Andrew J; Hu, Qiang; Meng, Xin; Cui, Hongsheng; Ding, Yongzhuo; Kang, Lu; Zhang, Yubo; Wang, Yuhua; Cui, Guangcheng; Li, Ping

    2016-06-01

    Altered brain activities in the cortico-striato-thalamocortical (CSTC) circuitry are implicated in the pathophysiology of obsessive-compulsive disorder (OCD). However, whether the underlying changes occur only within this circuitry or in large-scale networks is still not thoroughly understood. This study performed voxel-based functional connectivity analysis on resting-state functional magnetic resonance imaging (fMRI) data from thirty OCD patients and thirty healthy controls to investigate whole-brain intrinsic functional connectivity patterns in OCD. Relative to the healthy controls, OCD patients showed decreased functional connectivity within the CSTC circuitry but increased functional connectivity in other brain regions. Furthermore, decreased left caudate nucleus-thalamus connectivity within the CSTC circuitry was positively correlated with the illness duration of OCD. This study provides additional evidence that CSTC circuitry may play an essential role and alteration of large-scale brain networks may be involved in the pathophysiology of OCD. PMID:27143323

  11. Abnormal gray matter volume and resting-state functional connectivity in former heroin-dependent individuals abstinent for multiple years.

    PubMed

    Wang, Lubin; Zou, Feng; Zhai, Tianye; Lei, Yu; Tan, Shuwen; Jin, Xiao; Ye, Enmao; Shao, Yongcong; Yang, Yihong; Yang, Zheng

    2016-05-01

    Previous studies have suggested that heroin addiction is associated with structural and functional brain abnormalities. However, it is largely unknown whether these characteristics of brain abnormalities would be persistent or restored after long periods of abstinence. Considering the very high rates of relapse, we hypothesized that there may exist some latent neural vulnerabilities in abstinent heroin users. In this study, structural and resting-state functional magnetic resonance imaging data were collected from 30 former heroin-dependent (FHD) subjects who were drug free for more than 3 years and 30 non-addicted control (CN) volunteers. Voxel-based morphometry was used to identify possible gray matter volume differences between the FHD and CN groups. Alterations in resting-state functional connectivity in FHD were examined using brain areas with gray matter deficits as seed regions. Significantly reduced gray matter volume was observed in FHD in an area surrounding the parieto-occipital sulcus, which included the precuneus and cuneus. Functional connectivity analyses revealed that the FHD subjects showed reduced positive correlation within the default mode network and visual network and decreased negative correlation between the default mode network, visual network and task positive network. Moreover, the altered functional connectivity was correlated with self-reported impulsivity scores in the FHD subjects. Our findings suggest that disruption of large-scale brain systems is present in former heroin users even after multi-year abstinence, which could serve as system-level neural underpinnings for behavioral dysfunctions associated with addiction. PMID:25727574

  12. Possible Electromagnetic Effects on Abnormal Animal Behavior Before an Earthquake

    PubMed Central

    Hayakawa, Masashi

    2013-01-01

    Simple Summary Possible electromagnetic effects on abnormal animal behavior before earthquakes. Abstract The former statistical properties summarized by Rikitake (1998) on unusual animal behavior before an earthquake (EQ) have first been presented by using two parameters (epicentral distance (D) of an anomaly and its precursor (or lead) time (T)). Three plots are utilized to characterize the unusual animal behavior; (i) EQ magnitude (M) versus D, (ii) log T versus M, and (iii) occurrence histogram of log T. These plots are compared with the corresponding plots for different seismo-electromagnetic effects (radio emissions in different frequency ranges, seismo-atmospheric and -ionospheric perturbations) extensively obtained during the last 15–20 years. From the results of comparisons in terms of three plots, it is likely that lower frequency (ULF (ultra-low-frequency, f ≤ 1 Hz) and ELF (extremely-low-frequency, f ≤ a few hundreds Hz)) electromagnetic emissions exhibit a very similar temporal evolution with that of abnormal animal behavior. It is also suggested that a quantity of field intensity multiplied by the persistent time (or duration) of noise would play the primary role in abnormal animal behavior before an EQ. PMID:26487307

  13. Functionally reduced sensorimotor connections form with normal specificity despite abnormal muscle spindle development: the role of spindle-derived NT3

    PubMed Central

    Shneider, Neil A.; Mentis, George Z.; Schustak, Joshua; O’Donovan, Michael J.

    2009-01-01

    Summary The mechanisms controlling the formation of synaptic connections between muscle spindle afferents and spinal motor neurons are believed to be regulated by factors originating from muscle spindles. Here, we find that the connections form with appropriate specificity in mice with abnormal spindle development caused by the conditional elimination of the neuregulin1 receptor ErbB2 from muscle precursors. However, despite a modest (~30%) decrease in the number of afferent terminals on motor neuron somata, the amplitude of afferent-evoked synaptic potentials recorded in motor neurons was reduced by ~80%, suggesting that many of the connections that form are functionally silent. The selective elimination of neurotrophin 3 (NT3) from muscle spindles had no effect on the amplitude of afferent-evoked ventral root potentials until the second postnatal week, revealing a late role for spindle-derived NT3 in the functional maintenance of the connections. These findings indicate that spindle-derived factors regulate the strength of the connections, but not their initial formation or their specificity. PMID:19369542

  14. Abnormal Resting-State Functional Connectivity in Patients with Chronic Fatigue Syndrome: Results of Seed and Data-Driven Analyses.

    PubMed

    Gay, Charles W; Robinson, Michael E; Lai, Song; O'Shea, Andrew; Craggs, Jason G; Price, Donald D; Staud, Roland

    2016-02-01

    Although altered resting-state functional connectivity (FC) is a characteristic of many chronic pain conditions, it has not yet been evaluated in patients with chronic fatigue. Our objective was to investigate the association between fatigue and altered resting-state FC in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Thirty-six female subjects, 19 ME/CFS and 17 healthy controls, completed a fatigue inventory before undergoing functional magnetic resonance imaging. Two methods, (1) data driven and (2) model based, were used to estimate and compare the intraregional FC between both groups during the resting state (RS). The first approach using independent component analysis was applied to investigate five RS networks: the default mode network, salience network (SN), left frontoparietal networks (LFPN) and right frontoparietal networks, and the sensory motor network (SMN). The second approach used a priori selected seed regions demonstrating abnormal regional cerebral blood flow (rCBF) in ME/CFS patients at rest. In ME/CFS patients, Method-1 identified decreased intrinsic connectivity among regions within the LFPN. Furthermore, the FC of the left anterior midcingulate with the SMN and the connectivity of the left posterior cingulate cortex with the SN were significantly decreased. For Method-2, five distinct clusters within the right parahippocampus and occipital lobes, demonstrating significant rCBF reductions in ME/CFS patients, were used as seeds. The parahippocampal seed and three occipital lobe seeds showed altered FC with other brain regions. The degree of abnormal connectivity correlated with the level of self-reported fatigue. Our results confirm altered RS FC in patients with ME/CFS, which was significantly correlated with the severity of their chronic fatigue. PMID:26449441

  15. Post mTBI fatigue is associated with abnormal brain functional connectivity

    PubMed Central

    Nordin, Love Engström; Möller, Marika Christina; Julin, Per; Bartfai, Aniko; Hashim, Farouk; Li, Tie-Qiang

    2016-01-01

    This study set out to investigate the behavioral correlates of changes in resting-state functional connectivity before and after performing a 20 minute continuous psychomotor vigilance task (PVT) for patients with chronic post-concussion syndrome. Ten patients in chronic phase after mild traumatic brain injury (mTBI) with persisting symptoms of fatigue and ten matched healthy controls participated in the study. We assessed the participants’ fatigue levels and conducted resting-state fMRI before and after a sustained PVT. We evaluated the changes in brain functional connectivity indices in relation to the subject’s fatigue behavior using a quantitative data-driven analysis approach. We found that the PVT invoked significant mental fatigue and specific functional connectivity changes in mTBI patients. Furthermore, we found a significant linear correlation between self-reported fatigue and functional connectivity in the thalamus and middle frontal cortex. Our findings indicate that resting-state fMRI measurements may be a useful indicator of performance potential and a marker of fatigue level in the neural attentional system. PMID:26878885

  16. Post mTBI fatigue is associated with abnormal brain functional connectivity.

    PubMed

    Nordin, Love Engström; Möller, Marika Christina; Julin, Per; Bartfai, Aniko; Hashim, Farouk; Li, Tie-Qiang

    2016-01-01

    This study set out to investigate the behavioral correlates of changes in resting-state functional connectivity before and after performing a 20 minute continuous psychomotor vigilance task (PVT) for patients with chronic post-concussion syndrome. Ten patients in chronic phase after mild traumatic brain injury (mTBI) with persisting symptoms of fatigue and ten matched healthy controls participated in the study. We assessed the participants' fatigue levels and conducted resting-state fMRI before and after a sustained PVT. We evaluated the changes in brain functional connectivity indices in relation to the subject's fatigue behavior using a quantitative data-driven analysis approach. We found that the PVT invoked significant mental fatigue and specific functional connectivity changes in mTBI patients. Furthermore, we found a significant linear correlation between self-reported fatigue and functional connectivity in the thalamus and middle frontal cortex. Our findings indicate that resting-state fMRI measurements may be a useful indicator of performance potential and a marker of fatigue level in the neural attentional system. PMID:26878885

  17. Resting state functional MRI reveals abnormal network connectivity in orthostatic tremor.

    PubMed

    Benito-León, Julián; Louis, Elan D; Manzanedo, Eva; Hernández-Tamames, Juan Antonio; Álvarez-Linera, Juan; Molina-Arjona, José Antonio; Matarazzo, Michele; Romero, Juan Pablo; Domínguez-González, Cristina; Domingo-Santos, Ángela; Sánchez-Ferro, Álvaro

    2016-07-01

    Very little is known about the pathogenesis of orthostatic tremor (OT). We have observed that OT patients might have deficits in specific aspects of neuropsychological function, particularly those thought to rely on the integrity of the prefrontal cortex, which suggests a possible involvement of frontocerebellar circuits. We examined whether resting-state functional magnetic resonance imaging (fMRI) might provide further insights into the pathogenesis on OT. Resting-state fMRI data in 13 OT patients (11 women and 2 men) and 13 matched healthy controls were analyzed using independent component analysis, in combination with a "dual-regression" technique, to identify group differences in several resting-state networks (RSNs). All participants also underwent neuropsychological testing during the same session. Relative to healthy controls, OT patients showed increased connectivity in RSNs involved in cognitive processes (default mode network [DMN] and frontoparietal networks), and decreased connectivity in the cerebellum and sensorimotor networks. Changes in network integrity were associated not only with duration (DMN and medial visual network), but also with cognitive function. Moreover, in at least 2 networks (DMN and medial visual network), increased connectivity was associated with worse performance on different cognitive domains (attention, executive function, visuospatial ability, visual memory, and language). In this exploratory study, we observed selective impairments of RSNs in OT patients. This and other future resting-state fMRI studies might provide a novel method to understand the pathophysiological mechanisms of motor and nonmotor features of OT. PMID:27442678

  18. Abnormal EEG Complexity and Functional Connectivity of Brain in Patients with Acute Thalamic Ischemic Stroke

    PubMed Central

    Liu, Shuang; Guo, Jie; Meng, Jiayuan; Wang, Zhijun; Yao, Yang; Yang, Jiajia; Qi, Hongzhi; Ming, Dong

    2016-01-01

    Ischemic thalamus stroke has become a serious cardiovascular and cerebral disease in recent years. To date the existing researches mostly concentrated on the power spectral density (PSD) in several frequency bands. In this paper, we investigated the nonlinear features of EEG and brain functional connectivity in patients with acute thalamic ischemic stroke and healthy subjects. Electroencephalography (EEG) in resting condition with eyes closed was recorded for 12 stroke patients and 11 healthy subjects as control group. Lempel-Ziv complexity (LZC), Sample Entropy (SampEn), and brain network using partial directed coherence (PDC) were calculated for feature extraction. Results showed that patients had increased mean LZC and SampEn than the controls, which implied the stroke group has higher EEG complexity. For the brain network, the stroke group displayed a trend of weaker cortical connectivity, which suggests a functional impairment of information transmission in cortical connections in stroke patients. These findings suggest that nonlinear analysis and brain network could provide essential information for better understanding the brain dysfunction in the stroke and assisting monitoring or prognostication of stroke evolution. PMID:27403202

  19. Interpreting the effects of altered brain anatomical connectivity on fMRI functional connectivity: a role for computational neural modeling

    PubMed Central

    Horwitz, Barry; Hwang, Chuhern; Alstott, Jeff

    2013-01-01

    Recently, there have been a large number of studies using resting state fMRI to characterize abnormal brain connectivity in patients with a variety of neurological, psychiatric, and developmental disorders. However, interpreting what the differences in resting state fMRI functional connectivity (rsfMRI-FC) actually reflect in terms of the underlying neural pathology has proved to be elusive because of the complexity of brain anatomical connectivity. The same is the case for task-based fMRI studies. In the last few years, several groups have used large-scale neural modeling to help provide some insight into the relationship between brain anatomical connectivity and the corresponding patterns of fMRI-FC. In this paper we review several efforts at using large-scale neural modeling to investigate the relationship between structural connectivity and functional/effective connectivity to determine how alterations in structural connectivity are manifested in altered patterns of functional/effective connectivity. Because the alterations made in the anatomical connectivity between specific brain regions in the model are known in detail, one can use the results of these simulations to determine the corresponding alterations in rsfMRI-FC. Many of these simulation studies found that structural connectivity changes do not necessarily result in matching changes in functional/effective connectivity in the areas of structural modification. Often, it was observed that increases in functional/effective connectivity in the altered brain did not necessarily correspond to increases in the strength of the anatomical connection weights. Note that increases in rsfMRI-FC in patients have been interpreted in some cases as resulting from neural plasticity. These results suggest that this interpretation can be mistaken. The relevance of these simulation findings to the use of functional/effective fMRI connectivity as biomarkers for brain disorders is also discussed. PMID:24273500

  20. Abnormal functional connectivity density in patients with ischemic white matter lesions: An observational study.

    PubMed

    Ding, Ju-Rong; Ding, Xin; Hua, Bo; Xiong, Xingzhong; Wang, Qingsong; Chen, Huafu

    2016-09-01

    White matter lesions (WMLs) are frequently detected in elderly people. Previous structural and functional studies have demonstrated that WMLs are associated with cognitive and motor decline. However, the underlying mechanism of how WMLs lead to cognitive decline and motor disturbance remains unclear. We used functional connectivity density mapping (FCDM) to investigate changes in brain functional connectivity in 16 patients with ischemic WMLs and 13 controls. Both short- and long-range FCD maps were computed, and group comparisons were performed between the 2 groups. A correlation analysis was further performed between regions with altered FCD and cognitive test scores (Mini-Mental State Examination [MMSE] and Montreal Cognitive Assessment [MoCA]) in the patient group. We found that patients with ischemic WMLs showed reduced short-range FCD in the temporal cortex, primary motor cortex, and subcortical region, which may account for inadequate top-down attention, impaired motor, memory, and executive function associated with WMLs. The positive correlation between primary motor cortex and MoCA scores may provide evidence for the influences of cognitive function on behavioral performance. The inferior parietal cortex exhibited increased short-range FCD, reflecting a hyper bottom-up attention to compensate for the inadequate top-down attention for language comprehension and information retrieval in patients with WMLs. Moreover, the prefrontal and primary motor cortex showed increased long-range FCD and the former positively correlated with MoCA scores, which may suggest a strategy of cortical functional reorganization to compensate for motor and executive deficits. Our findings provide new insights into how WMLs cause cognitive and motor decline from cortical functional connectivity perspective. PMID:27603353

  1. Possible Electromagnetic Effects on Abnormal Animal Behavior Before an Earthquake.

    PubMed

    Hayakawa, Masashi

    2013-01-01

    The former statistical properties summarized by Rikitake (1998) on unusual animal behavior before an earthquake (EQ) have first been presented by using two parameters (epicentral distance (D) of an anomaly and its precursor (or lead) time (T)). Three plots are utilized to characterize the unusual animal behavior; (i) EQ magnitude (M) versus D, (ii) log T versus M, and (iii) occurrence histogram of log T. These plots are compared with the corresponding plots for different seismo-electromagnetic effects (radio emissions in different frequency ranges, seismo-atmospheric and -ionospheric perturbations) extensively obtained during the last 15-20 years. From the results of comparisons in terms of three plots, it is likely that lower frequency (ULF (ultra-low-frequency, f ≤ 1 Hz) and ELF (extremely-low-frequency, f ≤ a few hundreds Hz)) electromagnetic emissions exhibit a very similar temporal evolution with that of abnormal animal behavior. It is also suggested that a quantity of field intensity multiplied by the persistent time (or duration) of noise would play the primary role in abnormal animal behavior before an EQ. PMID:26487307

  2. Changes in Effective Connectivity by Propofol Sedation

    PubMed Central

    Soddu, Andrea; Boly, Melanie; Boveroux, Pierre; Vanhaudenhuyse, Audrey; Bruno, Marie-Aurélie; Gosseries, Olivia; Bonhomme, Vincent; Laureys, Steven; Noirhomme, Quentin

    2013-01-01

    Mechanisms of propofol-induced loss of consciousness remain poorly understood. Recent fMRI studies have shown decreases in functional connectivity during unconsciousness induced by this anesthetic agent. Functional connectivity does not provide information of directional changes in the dynamics observed during unconsciousness. The aim of the present study was to investigate, in healthy humans during an auditory task, the changes in effective connectivity resulting from propofol induced loss of consciousness. We used Dynamic Causal Modeling for fMRI (fMRI-DCM) to assess how causal connectivity is influenced by the anesthetic agent in the auditory system. Our results suggest that the dynamic observed in the auditory system during unconsciousness induced by propofol, can result in a mixture of two effects: a local inhibitory connectivity increase and a decrease in the effective connectivity in sensory cortices. PMID:23977030

  3. Abnormal functional connectivity of default mode sub-networks in autism spectrum disorder patients.

    PubMed

    Assaf, Michal; Jagannathan, Kanchana; Calhoun, Vince D; Miller, Laura; Stevens, Michael C; Sahl, Robert; O'Boyle, Jacqueline G; Schultz, Robert T; Pearlson, Godfrey D

    2010-10-15

    Autism spectrum disorders (ASDs) are characterized by deficits in social and communication processes. Recent data suggest that altered functional connectivity (FC), i.e. synchronous brain activity, might contribute to these deficits. Of specific interest is the FC integrity of the default mode network (DMN), a network active during passive resting states and cognitive processes related to social deficits seen in ASD, e.g. Theory of Mind. We investigated the role of altered FC of default mode sub-networks (DM-SNs) in 16 patients with high-functioning ASD compared to 16 matched healthy controls of short resting fMRI scans using independent component analysis (ICA). ICA is a multivariate data-driven approach that identifies temporally coherent networks, providing a natural measure of FC. Results show that compared to controls, patients showed decreased FC between the precuneus and medial prefrontal cortex/anterior cingulate cortex, DMN core areas, and other DM-SNs areas. FC magnitude in these regions inversely correlated with the severity of patients' social and communication deficits as measured by the Autism Diagnostic Observational Schedule and the Social Responsiveness Scale. Importantly, supplemental analyses suggest that these results were independent of treatment status. These results support the hypothesis that DM-SNs under-connectivity contributes to the core deficits seen in ASD. Moreover, these data provide further support for the use of data-driven analysis with resting-state data for illuminating neural systems that differ between groups. This approach seems especially well suited for populations where compliance with and performance of active tasks might be a challenge, as it requires minimal cooperation. PMID:20621638

  4. Abnormal functional connectivity of default mode sub-networks in autism spectrum disorder patients

    PubMed Central

    Assaf, Michal; Jagannathan, Kanchana; Calhoun, Vince D.; Miller, Laura; Stevens, Michael C.; Sahl, Robert; O'Boyle, Jacqueline G.; Schultz, Robert T.; Pearlson, Godfrey D.

    2011-01-01

    Autism spectrum disorders (ASDs) are characterized by deficits in social and communication processes. Recent data suggest that altered functional connectivity (FC), i.e. synchronous brain activity, might contribute to these deficits. Of specific interest is the FC integrity of the default mode network (DMN), a network active during passive resting states and cognitive processes related to social deficits seen in ASD, e.g. Theory of Mind. We investigated the role of altered FC of default mode sub-networks (DM-SNs) in 16 patients with high-functioning ASD compared to 16 matched healthy controls of short resting fMRI scans using independent component analysis (ICA). ICA is a multivariate data-driven approach that identifies temporally coherent networks, providing a natural measure of FC. Results show that compared to controls, patients showed decreased FC between the precuneus and medial prefrontal cortex/anterior cingulate cortex, DMN core areas, and other DM-SNs areas. FC magnitude in these regions inversely correlated with the severity of patients' social and communication deficits as measured by the Autism Diagnostic Observational Schedule and the Social Responsiveness Scale. Importantly, supplemental analyses suggest that these results were independent of treatment status. These results support the hypothesis that DM-SNs under-connectivity contributes to the core deficits seen in ASD. Moreover, these data provide further support for the use of data-driven analysis with resting-state data for illuminating neural systems that differ between groups. This approach seems especially well suited for populations where compliance with and performance of active tasks might be a challenge, as it requires minimal cooperation. PMID:20621638

  5. Thermally effective, electrically isolating heat intercept connections

    SciTech Connect

    Niemann, R.C.; Gonczy, J.D.; Nicol, T.H.

    1995-06-01

    Electrical and electronic equipment often require thermally effective beat intercept connections that provide electrical isolation. Such connections can be developed by clamping, with a thermal-interference fit, an electrically insulating cylindrical tube between a central disk and an outer ring. Heat flows radially through the disk-tube-ring assembly. Thermal effectiveness, i.e., {Delta}T for a given heat flux, and electrical isolation are controlled by tube geometry and material and by connection-assembly details. Connections of this type are being developed as cryogenic heat intercepts for electrical current leads that employ high-temperature superconductors. We discuss the design considerations and details of a beat intercept connection that transfers a 45-w thermal load at 60 K with a {Delta}T of {approx} 10 K while providing 7.5 kV electrical isolation. Prototype heat intercept connections have been evaluated for their thermal and electrical performance, and the results are presented.

  6. Abnormal brain activation and connectivity to standardized disorder-related visual scenes in social anxiety disorder.

    PubMed

    Heitmann, Carina Yvonne; Feldker, Katharina; Neumeister, Paula; Zepp, Britta Maria; Peterburs, Jutta; Zwitserlood, Pienie; Straube, Thomas

    2016-04-01

    Our understanding of altered emotional processing in social anxiety disorder (SAD) is hampered by a heterogeneity of findings, which is probably due to the vastly different methods and materials used so far. This is why the present functional magnetic resonance imaging (fMRI) study investigated immediate disorder-related threat processing in 30 SAD patients and 30 healthy controls (HC) with a novel, standardized set of highly ecologically valid, disorder-related complex visual scenes. SAD patients rated disorder-related as compared with neutral scenes as more unpleasant, arousing and anxiety-inducing than HC. On the neural level, disorder-related as compared with neutral scenes evoked differential responses in SAD patients in a widespread emotion processing network including (para-)limbic structures (e.g. amygdala, insula, thalamus, globus pallidus) and cortical regions (e.g. dorsomedial prefrontal cortex (dmPFC), posterior cingulate cortex (PCC), and precuneus). Functional connectivity analysis yielded an altered interplay between PCC/precuneus and paralimbic (insula) as well as cortical regions (dmPFC, precuneus) in SAD patients, which emphasizes a central role for PCC/precuneus in disorder-related scene processing. Hyperconnectivity of globus pallidus with amygdala, anterior cingulate cortex (ACC) and medial prefrontal cortex (mPFC) additionally underlines the relevance of this region in socially anxious threat processing. Our findings stress the importance of specific disorder-related stimuli for the investigation of altered emotion processing in SAD. Disorder-related threat processing in SAD reveals anomalies at multiple stages of emotion processing which may be linked to increased anxiety and to dysfunctionally elevated levels of self-referential processing reported in previous studies. PMID:26806013

  7. Evoked Effective Connectivity of the Human Neocortex

    PubMed Central

    Entz, László; Tóth, Emília; Keller, Corey J.; Bickel, Stephan; Groppe, David M.; Fabó, Dániel; Kozák, Lajos R.; Eroőss, Loránd; Ulbert, István; Mehta, Ashesh D.

    2016-01-01

    The role of cortical connectivity in brain function and pathology is increasingly being recognized. While in vivo magnetic resonance imaging studies have provided important insights into anatomical and functional connectivity, these methodologies are limited in their ability to detect electrophysiological activity and the causal relationships that underlie effective connectivity. Here, we describe results of cortico-cortical evoked potential (CCEP) mapping using single pulse electrical stimulation in 25 patients undergoing seizure monitoring with subdural electrode arrays. Mapping was performed by stimulating adjacent electrode pairs and recording CCEPs from the remainder of the electrode array. CCEPs reliably revealed functional networks and showed an inverse relationship to distance between sites. Coregistration to Brodmann areas (BA) permitted group analysis. Connections were frequently directional with 43% of early responses and 50% of late responses of connections reflecting relative dominance of incoming or outgoing connections. The most consistent connections were seen as outgoing from motor cortex, BA6–BA9, somatosensory (SS) cortex, anterior cingulate cortex, and Broca's area. Network topology revealed motor, SS, and premotor cortices along with BA9 and BA10 and language areas to serve as hubs for cortical connections. BA20 and BA39 demonstrated the most consistent dominance of outdegree connections, while BA5, BA7, auditory cortex, and anterior cingulum demonstrated relatively greater indegree. This multicenter, large-scale, directional study of local and long-range cortical connectivity using direct recordings from awake, humans will aid the interpretation of noninvasive functional connectome studies. PMID:25044884

  8. Abnormal Amygdalar Activation and Connectivity in Adolescents with Attention-Deficit/Hyperactivity Disorder

    ERIC Educational Resources Information Center

    Posner, Jonathan; Nagel, Bonnie J.; Maia, Tiago V.; Mechling, Anna; Oh, Milim; Wang, Zhishun; Peterson, Bradley S.

    2011-01-01

    Objective: Emotional reactivity is one of the most disabling symptoms associated with attention-deficit/hyperactivity disorder (ADHD). We aimed to identify neural substrates associated with emotional reactivity and to assess the effects of stimulants on those substrates. Method: We used functional magnetic resonance imaging (fMRI) to assess neural…

  9. The effect of abnormal cell proportion on specimen classifier performance

    NASA Technical Reports Server (NTRS)

    Castleman, K. R.; White, B. S.

    1981-01-01

    An analysis is presented of the results obtained from a cell classifier which is confronted with an abnormal/normal cell ratio which is different from the ratio assumed in the calibration of the classifier. False negative and false positive error rates are determined in advance for classifier operation, along with the necessary sample size in order to validate the predicted distributions. Changes are demonstrated to happen only regarding the false negative rate, where reductions in the abnormal cell rate below the expected rates would cause totally unreliable data. Substantial overproduction of abnormal cells would be quickly noticeable, while production rates beyond, but close to, the expected rates would only require more extensive sampling. Classifier systems for 10% proportions of abnormal cells are concluded to be possible, but difficulties are present with much lower rates

  10. Transistor Effect in Improperly Connected Transistors.

    ERIC Educational Resources Information Center

    Luzader, Stephen; Sanchez-Velasco, Eduardo

    1996-01-01

    Discusses the differences between the standard representation and a realistic representation of a transistor. Presents an experiment that helps clarify the explanation of the transistor effect and shows why transistors should be connected properly. (JRH)

  11. Effective Literacy Programs. Classroom Connections.

    ERIC Educational Resources Information Center

    Pinnell, Gay Su

    1999-01-01

    Effective literacy programs involve a wide range of reading and writing activities, all of which are necessary and which support learning in different ways. An essential part of the language arts curriculum involves direct instruction in reading. Many teachers are beginning to teach reading in small groups, a process called "guided reading."…

  12. Cytoskeletal abnormalities in amyotrophic lateral sclerosis: beneficial or detrimental effects?

    PubMed

    Julien, J P; Beaulieu, J M

    2000-11-01

    Cytoskeletal abnormalities have been reported in cases of amyotrophic lateral sclerosis (ALS) including abnormal inclusions containing neurofilaments (NFs) and/or peripherin, reduced mRNA levels for the NF light (NF-L) protein and mutations in the NF heavy (NF-H) gene. Recently, transgenic mouse approaches have been used to address whether cytoskeletal changes may contribute to motor neuron disease. Mice lacking one of the three NF subunits are viable and do not develop motor neuron disease. Nonetheless, mice with null mutations for NF-L or for both NF-M and NF-H genes developed severe atrophy of ventral and dorsal root axons. The atrophic process is associated with hind limb paralysis during aging in mice deficient for both NF-M and NF-H proteins. The overexpression in mice of transgenes coding for wild-type or mutant NF proteins can provoke abnormal NF accumulations, axonal atrophy and sometimes motor dysfunction. However, the perikaryal NF accumulations are generally well tolerated by motor neurons and, except for expression of a mutant NF-L transgene, they did not provoke massive motor neuron death. Increasing the levels of perikaryal NF proteins may even confer protection in motor neuron disease caused by ALS-linked mutations in the superoxide dismutase (SOD1). In contrast, the overexpression of wild-type peripherin, a type of IF gene upregulated by inflammatory cytokines, provoked the formation of toxic IF inclusions with the high-molecular-weight NF proteins resulting in the death of motor neurons during aging. These results together with the detection of peripherin inclusions at early stage of disease in mice expressing mutant SOD1 suggest that IF inclusions containing peripherin may play a contributory role in ALS pathogenesis. PMID:11090858

  13. Noise Effects on the Complex Patterns of Abnormal Heartbeats

    SciTech Connect

    Schulte-Frohlinde, Verena; Ashkenazy, Yosef; Ivanov, Plamen Ch.; Glass, Leon; Goldberger, Ary L.; Stanley, H. Eugene

    2001-08-06

    Patients at high risk for sudden death often exhibit complex heart rhythms in which abnormal heartbeats are interspersed with normal heartbeats. We analyze such a complex rhythm in a single patient over a 12-h period and show that the rhythm can be described by a theoretical model consisting of two interacting oscillators with stochastic elements. By varying the magnitude of the noise, we show that for an intermediate level of noise, the model gives best agreement with key statistical features of the dynamics.

  14. Mapping Smoking Addiction Using Effective Connectivity Analysis

    PubMed Central

    Tang, Rongxiang; Razi, Adeel; Friston, Karl J.; Tang, Yi-Yuan

    2016-01-01

    Prefrontal and parietal cortex, including the default mode network (DMN; medial prefrontal cortex (mPFC), and posterior cingulate cortex, PCC), have been implicated in addiction. Nonetheless, it remains unclear which brain regions play a crucial role in smoking addiction and the relationship among these regions. Since functional connectivity only measures correlations, addiction-related changes in effective connectivity (directed information flow) among these distributed brain regions remain largely unknown. Here we applied spectral dynamic causal modeling (spDCM) to resting state fMRI to characterize changes in effective connectivity among core regions in smoking addiction. Compared to nonsmokers, smokers had reduced effective connectivity from PCC to mPFC and from RIPL to mPFC, a higher self-inhibition within PCC and a reduction in the amplitude of endogenous neuronal fluctuations driving the mPFC. These results indicate that spDCM can differentiate the functional architectures between the two groups, and may provide insight into the brain mechanisms underlying smoking addiction. Our results also suggest that future brain-based prevention and intervention in addiction should consider the amelioration of mPFC-PCC-IPL circuits. PMID:27199716

  15. Investigation of defect-induced abnormal body current in fin field-effect-transistors

    SciTech Connect

    Liu, Kuan-Ju; Tsai, Jyun-Yu; Lu, Ying-Hsin; Liu, Xi-Wen; Chang, Ting-Chang; Chen, Ching-En; Yang, Ren-Ya; Cheng, Osbert; Huang, Cheng-Tung

    2015-08-24

    This letter investigates the mechanism of abnormal body current at the linear region in n-channel high-k/metal gate stack fin field effect transistors. Unlike body current, which is generated by impact ionization at high drain voltages, abnormal body current was found to increase with decreasing drain voltages. Notably, the unusual body leakage only occurs in three-dimensional structure devices. Based on measurements under different operation conditions, the abnormal body current can be attributed to fin surface defect-induced leakage current, and the mechanism is electron tunneling to the fin via the defects, resulting in holes left at the body terminal.

  16. Abnormal Functional Connectivity of the Amygdala-Based Network in Resting-State fMRI in Adolescents with Generalized Anxiety Disorder

    PubMed Central

    Liu, Wen-jing; Yin, Da-zhi; Cheng, Wen-hong; Fan, Ming-xia; You, Mei-na; Men, Wei-wei; Zang, Li-li; Shi, Dian-hong; Zhang, Fang

    2015-01-01

    Background We aimed to investigate the disruptions of functional connectivity of amygdala-based networks in adolescents with untreated generalized anxiety disorder (GAD). Material/Methods A total of 26 adolescents with first-episode GAD and 20 normal age-matched volunteers underwent resting-state and T1 functional magnetic resonance imaging (fMRI). We analyzed the correlation of fMRI signal fluctuation between the amygdala and other brain regions. The variation of amygdala-based functional connectivity and its correlation with anxiety severity were investigated. Results Decreased functional connectivity was found between the left amygdala and left dorsolateral prefrontal cortex. An increased right amygdala functional connectivity with right posterior and anterior lobes of the cerebellum, insula, superior temporal gyrus, putamen, and right amygdala were found in our study. Negative correlations between GAD scores and functional connectivity of the right amygdala with the cerebellum were also observed in the GAD adolescents. Conclusions Adolescents with GAD have abnormalities in brain regions associated with the emotional processing pathways. PMID:25673008

  17. Effect of abnormal fracture mechanisms on fiber lifetime evaluation

    NASA Astrophysics Data System (ADS)

    Bubnov, Mikhail M.; Semjonov, Sergey L.

    1996-01-01

    Optical glass fibers can exhibit a transition in slope of their static fatigue behavior ('knee' phenomenon). This effect was previously supposed to reduce fiber lifetime. The 'knee' phenomenon as well as the phenomenon of abrupt increase of the flaw size ('pop-in') are re- examined in this paper. It is shown that under normal proof-test conditions these two effects have no tangible impact on the fiber service life estimations.

  18. Abnormal functional connectivity density in first-episode, drug-naive adult patients with major depressive disorder.

    PubMed

    Zou, Ke; Gao, Qing; Long, Zhiliang; Xu, Fei; Sun, Xiao; Chen, Huafu; Sun, Xueli

    2016-04-01

    Previous studies have found evidence of brain functional connectivity (FC) changes with pre-selected region-of-interest (ROI) method in major depressive disorder (MDD). However, these studies could not completely exclude personal inequality when drawing ROIs manually and did not measure the total number of FC for each voxel. Here, we firstly applied functional connectivity density (FCD) mapping, a voxel-based analysis to locate the hubs with amount changes of FC between 22 first-episode, drug-naive adult MDD patients and 22 healthy control (HC) subjects. Both short-range (local) FCD and long-range (distal) FCD were measured. The relationships of FCD changes with Hamilton Depression Rating Scale (HAMD) scores and illness duration were also explored. Compared with the HC group, MDD patients showed significantly decreased short-range FCD in the left superior temporal gyrus (STG), the right orbital frontal cortex (OFC) and bilateral precuneus, while significantly decreased long-range FCD was found in bilateral middle occipital gyrus (MOG), superior occipital gyrus (SOG) and right calcarine. These results firstly demonstrated both local and distal alterations of connection amount at voxel level, and highlighted that the OFC, the precuneus, the STG and the visual cortex were important brain network hubs for first-episode, drug-naive adult MDD patients. Our findings were complementary for previous structural and functional studies in MDD patients, and provided new evidence of the dysfunction of connection hubs in the pathophysiology of MDD at voxel level. PMID:26826535

  19. Effective connectivity: Influence, causality and biophysical modeling

    PubMed Central

    Valdes-Sosa, Pedro A.; Roebroeck, Alard; Daunizeau, Jean; Friston, Karl

    2011-01-01

    This is the final paper in a Comments and Controversies series dedicated to “The identification of interacting networks in the brain using fMRI: Model selection, causality and deconvolution”. We argue that discovering effective connectivity depends critically on state-space models with biophysically informed observation and state equations. These models have to be endowed with priors on unknown parameters and afford checks for model Identifiability. We consider the similarities and differences among Dynamic Causal Modeling, Granger Causal Modeling and other approaches. We establish links between past and current statistical causal modeling, in terms of Bayesian dependency graphs and Wiener–Akaike–Granger–Schweder influence measures. We show that some of the challenges faced in this field have promising solutions and speculate on future developments. PMID:21477655

  20. Improvement of white matter and functional connectivity abnormalities by repetitive transcranial magnetic stimulation in crossed aphasia in dextral

    PubMed Central

    Lu, Haitao; Wu, Haiyan; Cheng, Hewei; Wei, Dongjie; Wang, Xiaoyan; Fan, Yong; Zhang, Hao; Zhang, Tong

    2014-01-01

    As a special aphasia, the occurrence of crossed aphasia in dextral (CAD) is unusual. This study aims to improve the language ability by applying 1 Hz repetitive transcranial magnetic stimulation (rTMS). We studied multiple modality imaging of structural connectivity (diffusion tensor imaging), functional connectivity (resting fMRI), PET, and neurolinguistic analysis on a patient with CAD. Furthermore, we applied rTMS of 1 Hz for 40 times and observed the language function improvement. The results indicated that a significantly reduced structural and function connectivity was found in DTI and fMRI data compared with the control. The PET imaging showed hypo-metabolism in right hemisphere and left cerebellum. In conclusion, one of the mechanisms of CAD is that right hemisphere is the language dominance. Stimulating left Wernicke area could improve auditory comprehension, stimulating left Broca’s area could enhance expression, and the results outlasted 6 months by 1 Hz rTMS balancing the excitability inter-hemisphere in CAD. PMID:25419415

  1. Abnormal Resting-State Functional Connectivity Strength in Mild Cognitive Impairment and Its Conversion to Alzheimer's Disease

    PubMed Central

    Li, Yuxia; Wang, Xiaoni; Li, Yongqiu; Sun, Yu; Sheng, Can; Li, Hongyan; Li, Xuanyu; Yu, Yang; Chen, Guanqun; Hu, Xiaochen; Jing, Bin; Wang, Defeng; Li, Kuncheng; Jessen, Frank; Han, Ying

    2016-01-01

    Individuals diagnosed with mild cognitive impairment (MCI) are at high risk of transition to Alzheimer's disease (AD). However, little is known about functional characteristics of the conversion from MCI to AD. Resting-state functional magnetic resonance imaging was performed in 25 AD patients, 31 MCI patients, and 42 well-matched normal controls at baseline. Twenty-one of the 31 MCI patients converted to AD at approximately 24 months of follow-up. Functional connectivity strength (FCS) and seed-based functional connectivity analyses were used to assess the functional differences among the groups. Compared to controls, subjects with MCI and AD showed decreased FCS in the default-mode network and the occipital cortex. Importantly, the FCS of the left angular gyrus and middle occipital gyrus was significantly lower in MCI-converters as compared with MCI-nonconverters. Significantly decreased functional connectivity was found in MCI-converters compared to nonconverters between the left angular gyrus and bilateral inferior parietal lobules, dorsolateral prefrontal and lateral temporal cortices, and the left middle occipital gyrus and right middle occipital gyri. We demonstrated gradual but progressive functional changes during a median 2-year interval in patients converting from MCI to AD, which might serve as early indicators for the dysfunction and progression in the early stage of AD. PMID:26843991

  2. Transitory versus Persistent Effects of Connectivity in Environmentally Homogeneous Metacommunities

    PubMed Central

    Limberger, Romana; Wickham, Stephen A.

    2012-01-01

    While the effect of habitat connectivity on local and regional diversity has been analysed in a number of studies, time-dependent dynamics in metacommunities have received comparatively little consideration. When local patches of a metacommunity are identical in environmental conditions but differ in initial community composition, dispersal among patches may result in homogenization of local communities. In a microcosm experiment with benthic ciliates, we tested the hypothesis that the effect of connectivity on diversity is time-dependent and only transitory, with the degree of connectivity affecting the time to homogenization but not the final outcome. Six microcosms were connected to a metacommunity with one of three levels of connectivity. The six patches differed in initial community composition but were identical in environmental conditions. We found a time-dependent and transitory effect of connectivity on local and regional richness and on local Shannon diversity, while Bray-Curtis dissimilarity and regional Shannon diversity were persistently affected by connectivity. Local richness increased and regional richness decreased with connectivity during the initial phase of the experiment but soon converged to similar values in all three connectivity treatments. Local Shannon diversity was unimodally related to time, with maximum diversity reached sooner with high than with medium or low connectivity. Eventually, however, local diversity converged to similar values irrespective of connectivity. At the regional scale, Shannon diversity was persistently lower with high than with low connectivity. While initial differences in community composition vanished with medium and high connectivity, they were maintained with low connectivity resulting in persistently high beta and regional diversity. The effect of connectivity on ciliate community composition translated down to the algal resource, as stronger dominance of the superior competitor with high and medium

  3. Protective Effects of Quetiapine on Metabolic and Inflammatory Abnormalities in Schizophrenic Patients during Exacerbated Stage.

    PubMed

    Kao, Yu-Chen; Ko, Chih-Yuan; Wang, Sheng-Chiang; Liu, Yia-Ping

    2016-04-30

    Inflammation has been considered important in the pathogenesis of schizophrenia. Increasing evidence reveals that patients with schizophrenia have abnormal expression of cytokines, which are related to development of metabolic abnormalities. Metabolic abnormality has become a critical issue, though its longitudinal relationship with the disorder, such as the antipsychotics influence, is unclear. We aimed to investigate whether abnormalities of metabolic parameters and cytokine levels in acute exacerbated schizophrenic patients existed, and whether intervention of antipsychotic could help. The present study analyzed peripheral cytokines and metabolic/hemodynamic parameters in healthy controls and acute exacerbated schizophrenic patients hospitalized for three weeks under the unique treatment of quetiapine, a well-known second-generation antipsychotic. Our results showed that patients with schizophrenia were predisposed to metabolic abnormalities in acute exacerbation, including body mass index (BMI) and waist circumference (WC). The patients were also prone to dysglycemia, lower high-density lipoprotein cholesterol (HDL-c) levels, and higher blood pressure with concomitant of elevation of interleukin (IL)-2, IL-6 and IL-10 in which IL-6 was associated with BMI. After quetiapine treatment, IL-2, IL-6 and IL-10 remained higher than the controls, but IL-10 was significantly decreased in follow-up comparison. Glycemic-related indexes, HDL-c and IL-10 levels were significantly changed by variance analysis. Results of the present study imply that acute exacerbated schizophrenic patients with metabolism abnormalities may involve disruption of expression of cytokines, and that quetiapine may have therapeutic effects. Nonetheless, metabolism parameters of patients undergoing treatment with quetiapine should be closely monitored. PMID:27080462

  4. Synergistic effect of polymorphisms of paraoxonase gene cluster and arsenic exposure on electrocardiogram abnormality

    SciTech Connect

    Liao, Y.-T.; Li, W.-F.; Chen, C.-J.; Prineas, Ronald J.; Chen, Wei J.; Zhang Zhuming; Sun, C.-W.; Wang, S.-L.

    2009-09-01

    Arsenic has been linked to increased prevalence of cancer and cardiovascular disease (CVD), but the long-term impact of arsenic exposure remains unclear. Human paraoxonase (PON1) is a high-density lipoprotein-associated antioxidant enzyme which hydrolyzes oxidized lipids and is thought to be protective against atherosclerosis, but evidence remains limited to case-control studies. Only recently have genes encoding enzymes responsible for arsenic metabolism, such as AS3MT and GSTO, been cloned and characterized. This study was designed to evaluate the synergistic interaction of genetic factors and arsenic exposure on electrocardiogram abnormality. A total of 216 residents from three tap water implemented villages of previous arseniasis-hyperendemic regions in Taiwan were prospectively followed for an average of 8 years. For each resident, a 12-lead conventional electrocardiogram (ECG) was recorded and coded by Minnesota Code standard criteria. Eight functional polymorphisms of PON1, PON2, AS3MT, GSTO1, and GSTO2 were examined for genetic susceptibility to ECG abnormality. Among 42 incident cases with ECG deterioration identified among 121 baseline-normal subjects, arsenic exposure was significantly correlated with incidence of ECG abnormality. In addition, polymorphisms in two paraoxonase genes were also found associated with the incidence of ECG abnormality. A haplotype R-C-S constituted by polymorphisms of PON1 Q192R, -108C/T and PON2 C311S was linked to the increased risk. Subjects exposed to high levels of As (cumulative As exposure > 14.7 ppm-year or drinking artesian well water > 21 years) and carrying the R-C-S haplotype had significantly increased risks for ECG abnormality over those with only one risk factor. Results of this study showed a long-term arsenic effect on ECG abnormality and significant gene-gene and gene-environment interactions linked to the incidence of CVD. This finding might have important implications for a novel and potentially useful

  5. Better models are more effectively connected models

    NASA Astrophysics Data System (ADS)

    Nunes, João Pedro; Bielders, Charles; Darboux, Frederic; Fiener, Peter; Finger, David; Turnbull-Lloyd, Laura; Wainwright, John

    2016-04-01

    The concept of hydrologic and geomorphologic connectivity describes the processes and pathways which link sources (e.g. rainfall, snow and ice melt, springs, eroded areas and barren lands) to accumulation areas (e.g. foot slopes, streams, aquifers, reservoirs), and the spatial variations thereof. There are many examples of hydrological and sediment connectivity on a watershed scale; in consequence, a process-based understanding of connectivity is crucial to help managers understand their systems and adopt adequate measures for flood prevention, pollution mitigation and soil protection, among others. Modelling is often used as a tool to understand and predict fluxes within a catchment by complementing observations with model results. Catchment models should therefore be able to reproduce the linkages, and thus the connectivity of water and sediment fluxes within the systems under simulation. In modelling, a high level of spatial and temporal detail is desirable to ensure taking into account a maximum number of components, which then enables connectivity to emerge from the simulated structures and functions. However, computational constraints and, in many cases, lack of data prevent the representation of all relevant processes and spatial/temporal variability in most models. In most cases, therefore, the level of detail selected for modelling is too coarse to represent the system in a way in which connectivity can emerge; a problem which can be circumvented by representing fine-scale structures and processes within coarser scale models using a variety of approaches. This poster focuses on the results of ongoing discussions on modelling connectivity held during several workshops within COST Action Connecteur. It assesses the current state of the art of incorporating the concept of connectivity in hydrological and sediment models, as well as the attitudes of modellers towards this issue. The discussion will focus on the different approaches through which connectivity

  6. Effects of chronic and acute stimulants on brain functional connectivity hubs.

    PubMed

    Konova, Anna B; Moeller, Scott J; Tomasi, Dardo; Goldstein, Rita Z

    2015-12-01

    The spatial distribution and strength of information processing 'hubs' are essential features of the brain׳s network topology, and may thus be particularly susceptible to neuropsychiatric disease. Despite growing evidence that drug addiction alters functioning and connectivity of discrete brain regions, little is known about whether chronic drug use is associated with abnormalities in this network-level organization, and if such abnormalities could be targeted for intervention. We used functional connectivity density (FCD) mapping to evaluate how chronic and acute stimulants affect brain hubs (i.e., regions with many short-range or long-range functional connections). Nineteen individuals with cocaine use disorders (CUD) and 15 healthy controls completed resting-state fMRI scans following a randomly assigned dose of methylphenidate (MPH; 20mg) or placebo. Short-range and long-range FCD maps were computed for each participant and medication condition. CUD participants had increased short-range and long-range FCD in the ventromedial prefrontal cortex, posterior cingulate/precuneus, and putamen/amygdala, which in areas of the default mode network correlated with years of use. Across participants, MPH decreased short-range FCD in the thalamus/putamen, and decreased long-range FCD in the supplementary motor area and postcentral gyrus. Increased density of short-range and long-range functional connections to default mode hubs in CUD suggests an overrepresentation of these resource-expensive hubs. While the effects of MPH on FCD were only partly overlapping with those of CUD, MPH-induced reduction in the density of short-range connections to the putamen/thalamus, a network of core relevance to habit formation and addiction, suggests that some FCD abnormalities could be targeted for intervention. PMID:25721787

  7. Connectivity

    ERIC Educational Resources Information Center

    Grush, Mary, Ed.

    2006-01-01

    Connectivity has dramatically changed the landscape of higher education IT. From "on-demand" services for net-gen students and advanced eLearning systems for faculty, to high-performance computing grid resources for researchers, IT now provides more networked services than ever to connect campus constituents to each other and to the world.…

  8. Dynamic effective connectivity of inter-areal brain circuits.

    PubMed

    Battaglia, Demian; Witt, Annette; Wolf, Fred; Geisel, Theo

    2012-01-01

    Anatomic connections between brain areas affect information flow between neuronal circuits and the synchronization of neuronal activity. However, such structural connectivity does not coincide with effective connectivity (or, more precisely, causal connectivity), related to the elusive question "Which areas cause the present activity of which others?". Effective connectivity is directed and depends flexibly on contexts and tasks. Here we show that dynamic effective connectivity can emerge from transitions in the collective organization of coherent neural activity. Integrating simulation and semi-analytic approaches, we study mesoscale network motifs of interacting cortical areas, modeled as large random networks of spiking neurons or as simple rate units. Through a causal analysis of time-series of model neural activity, we show that different dynamical states generated by a same structural connectivity motif correspond to distinct effective connectivity motifs. Such effective motifs can display a dominant directionality, due to spontaneous symmetry breaking and effective entrainment between local brain rhythms, although all connections in the considered structural motifs are reciprocal. We show then that transitions between effective connectivity configurations (like, for instance, reversal in the direction of inter-areal interactions) can be triggered reliably by brief perturbation inputs, properly timed with respect to an ongoing local oscillation, without the need for plastic synaptic changes. Finally, we analyze how the information encoded in spiking patterns of a local neuronal population is propagated across a fixed structural connectivity motif, demonstrating that changes in the active effective connectivity regulate both the efficiency and the directionality of information transfer. Previous studies stressed the role played by coherent oscillations in establishing efficient communication between distant areas. Going beyond these early proposals, we advance

  9. Accelerating networks: Effects of preferential connections

    NASA Astrophysics Data System (ADS)

    Jeon, Y.-P.; McCoy, B. J.

    2007-12-01

    Networks are commonly observed structures in complex systems with interacting and interdependent parts that self-organize. For nonlinearly growing networks, when the total number of connections increases faster than the total number of nodes, the network is said to accelerate. We propose a systematic model for the dynamics of growing networks represented by distribution kinetics equations. We define the nodal-linkage distribution, construct a population dynamics equation based on the association-dissociation process, and perform the moment calculations to describe the dynamics of such networks. For nondirectional networks with finite numbers of nodes and connections, the moments are the total number of nodes, the total number of connections, and the degree (the average number of connections per node), represented by the average moment. Size independent rate coefficients yield an exponential network describing the network without preferential attachment, and size dependent rate coefficients produce a power law network with preferential attachment. The model quantitatively describes accelerating network growth data for a supercomputer (Earth Simulator), for regulatory gene networks, and for the Internet.

  10. Effects of hyperbaric oxygen on eye tracking abnormalities in males after mild traumatic brain injury.

    PubMed

    Cifu, David X; Hoke, Kathy W; Wetzel, Paul A; Wares, Joanna R; Gitchel, George; Carne, William

    2014-01-01

    The effects of hyperbaric oxygen (HBO2) on eye movement abnormalities in 60 military servicemembers with at least one mild traumatic brain injury (TBI) from combat were examined in a single-center, randomized, double-blind, sham-controlled, prospective study at the Naval Medicine Operational Training Center. During the 10 wk of the study, each subject was delivered a series of 40, once a day, hyperbaric chamber compressions at a pressure of 2.0 atmospheres absolute (ATA). At each session, subjects breathed one of three preassigned oxygen fractions (10.5%, 75%, or 100%) for 1 h, resulting in an oxygen exposure equivalent to breathing either surface air, 100% oxygen at 1.5 ATA, or 100% oxygen at 2.0 ATA, respectively. Using a standardized, validated, computerized eye tracking protocol, fixation, saccades, and smooth pursuit eye movements were measured just prior to intervention and immediately postintervention. Between and within groups testing of pre- and postintervention means revealed no significant differences on eye movement abnormalities and no significant main effect for HBO2 at either 1.5 ATA or 2.0 ATA equivalent compared with the sham-control. This study demonstrated that neither 1.5 nor 2.0 ATA equivalent HBO2 had an effect on postconcussive eye movement abnormalities after mild TBI when compared with a sham-control. PMID:25436771

  11. Effect of Resection of Lung Tumours on the Steroid Abnormalities in Patients with Lung Cancer

    PubMed Central

    Rao, L. G. S.

    1971-01-01

    The urinary excretion of androsterone, aetiocholanolone, total 17-oxosteroids, and 17-hydroxycorticosteroids (17-OHCS) was measured in 40 patients with lung cancer three days before resection and again 10-15 days after resection of their lung tumours. There was a significant postoperative increase in the excretion of 17-OHCS but a significant decrease in the excretion of androsterone and aetiocholanolone, resulting in an increase of the preoperative abnormalities in steroid excretion in these patients. Since there was no change in steroid excretion towards normal after resection of the lung tumours, it seems that the steroid abnormalities found in lung cancer are not the effect of the presence of the lung tumours. As the excretions of 17-OHCS and 11-deoxy-17-oxosteroids change in opposite directions after resection, it is suggested that a dissociation of factors that control the excretion of these two groups of steroids takes place as a response to surgical stress in patients with lung cancer. PMID:5130212

  12. Effect of Green Tea Extract on Doxorubicin Induced Cardiovascular Abnormalities: Antioxidant Action

    PubMed Central

    Patil, Leena; Balaraman, R

    2011-01-01

    Doxorubicin (DOX) induces oxidative stress leading to cardiovascular abnormalities. Green tea extract (GTE) is reported to possess antioxidant activity mainly by means of its polyphenolic constituent, catechins. Our study was aimed to find out the effect of GTE (100 mg/kg / day p.o. for 28 days) on DOX induced (3 mg/kg, IP on days 1, 7, 14, 21, 28) cardiovascular abnormalities in rat heart. DOX treatment led to significant increase in blood pressure, ST interval, serum levels of LDH, CK, SGOT, lipid peroxidation .The antioxidant enzymes such as super oxide dismutase, catalase and reduced-glutathione were decreased considerably in the heart of DOX treated rats as compared to the normal control. A combined treatment with GTE and DOX showed a considerable decrease in serum markers of cardiotoxicity such as LDH, CK, SGOT and lipid peroxides. There was significant increase in the activities of antioxidant enzymes and also showed improvement in hemodynamic parameters and ECG changes as compared to DOX treated animals. DOX treatment caused disorganization of myocardial tissue which was restored in animals treated with GTE along with DOX. Thus it can be concluded that GTE possesses an antioxidant activity and by virtue of this action it can protect the heart from DOX induced cardiovascular abnormalities. PMID:24363686

  13. Behavior Modulates Effective Connectivity between Cortex and Striatum

    PubMed Central

    Nakhnikian, Alexander; Rebec, George V.; Grasse, Leslie M.; Dwiel, Lucas L.; Shimono, Masanori; Beggs, John M.

    2014-01-01

    It has been notoriously difficult to understand interactions in the basal ganglia because of multiple recurrent loops. Another complication is that activity there is strongly dependent on behavior, suggesting that directional interactions, or effective connections, can dynamically change. A simplifying approach would be to examine just the direct, monosynaptic projections from cortex to striatum and contrast this with the polysynaptic feedback connections from striatum to cortex. Previous work by others on effective connectivity in this pathway indicated that activity in cortex could be used to predict activity in striatum, but that striatal activity could not predict cortical activity. However, this work was conducted in anesthetized or seizing animals, making it impossible to know how free behavior might influence effective connectivity. To address this issue, we applied Granger causality to local field potential signals from cortex and striatum in freely behaving rats. Consistent with previous results, we found that effective connectivity was largely unidirectional, from cortex to striatum, during anesthetized and resting states. Interestingly, we found that effective connectivity became bidirectional during free behaviors. These results are the first to our knowledge to show that striatal influence on cortex can be as strong as cortical influence on striatum. In addition, these findings highlight how behavioral states can affect basal ganglia interactions. Finally, we suggest that this approach may be useful for studies of Parkinson's or Huntington's diseases, in which effective connectivity may change during movement. PMID:24618981

  14. Associations of postural knowledge and basic motor skill with dyspraxia in autism: implication for abnormalities in distributed connectivity and motor learning.

    PubMed

    Dowell, Lauren R; Mahone, E Mark; Mostofsky, Stewart H

    2009-09-01

    Children with autism often have difficulty performing skilled movements. Praxis performance requires basic motor skill, knowledge of representations of the movement (mediated by parietal regions), and transcoding of these representations into movement plans (mediated by premotor circuits). The goals of this study were (a) to determine whether dyspraxia in autism is associated with impaired representational ("postural") knowledge and (b) to examine the contributions of postural knowledge and basic motor skill to dyspraxia in autism. Thirty-seven children with autism spectrum disorder (ASD) and 50 typically developing (TD) children, ages 8-13, completed (a) an examination of basic motor skills, (b) a postural knowledge test assessing praxis discrimination, and (c) a praxis examination. Children with ASD showed worse basic motor skill and postural knowledge than did controls. The ASD group continued to show significantly poorer praxis than did controls after accounting for age, IQ, basic motor skill, and postural knowledge. Dyspraxia in autism appears to be associated with impaired formation of spatial representations, as well as transcoding and execution. Distributed abnormality across parietal, premotor, and motor circuitry, as well as anomalous connectivity, may be implicated. PMID:19702410

  15. Associations of Postural Knowledge and Basic Motor Skill with Dyspraxia in Autism: Implication for Abnormalities in Distributed Connectivity and Motor Learning

    PubMed Central

    Dowell, Lauren R.; Mahone, E. Mark; Mostofsky, Stewart H.

    2009-01-01

    Children with autism often have difficulty performing skilled movements. Praxis performance requires basic motor skill, knowledge of representations of the movement (mediated by parietal regions), and transcoding of these representations into movement plans (mediated by premotor circuits). The goals of this study were: (a) to determine whether dyspraxia in autism is associated with impaired representational (“postural”) knowledge, and (b) to examine the contributions of postural knowledge and basic motor skill to dyspraxia in autism. Thirty-seven children with autism spectrum disorder (ASD) and 50 typically developing (TD) children, ages 8–13, completed: (a) an examination of basic motor skills, (b) a postural knowledge test assessing praxis discrimination, and (c) a praxis examination. Children with ASD showed worse basic motor skill and postural knowledge than controls. The ASD group continued to show significantly poorer praxis than controls after accounting for age, IQ, basic motor skill, and postural knowledge. Dyspraxia in autism appears to be associated with impaired formation of spatial representations, as well as transcoding and execution. Distributed abnormality across parietal, premotor, and motor circuitry, as well as anomalous connectivity may be implicated. PMID:19702410

  16. Effects of local and global network connectivity on synergistic epidemics

    NASA Astrophysics Data System (ADS)

    Broder-Rodgers, David; Pérez-Reche, Francisco J.; Taraskin, Sergei N.

    2015-12-01

    Epidemics in networks can be affected by cooperation in transmission of infection and also connectivity between nodes. An interplay between these two properties and their influence on epidemic spread are addressed in the paper. A particular type of cooperative effects (called synergy effects) is considered, where the transmission rate between a pair of nodes depends on the number of infected neighbors. The connectivity effects are studied by constructing networks of different topology, starting with lattices with only local connectivity and then with networks that have both local and global connectivity obtained by random bond-rewiring to nodes within a certain distance. The susceptible-infected-removed epidemics were found to exhibit several interesting effects: (i) for epidemics with strong constructive synergy spreading in networks with high local connectivity, the bond rewiring has a negative role in epidemic spread, i.e., it reduces invasion probability; (ii) in contrast, for epidemics with destructive or weak constructive synergy spreading on networks of arbitrary local connectivity, rewiring helps epidemics to spread; (iii) and, finally, rewiring always enhances the spread of epidemics, independent of synergy, if the local connectivity is low.

  17. Regional Abnormality of Grey Matter in Schizophrenia: Effect from the Illness or Treatment?

    PubMed

    Yue, Ying; Kong, Li; Wang, Jijun; Li, Chunbo; Tan, Ling; Su, Hui; Xu, Yifeng

    2016-01-01

    Both schizophrenia and antipsychotic treatment are known to modulate brain morphology. However, it is difficult to establish whether observed structural brain abnormalities are due to disease or the effects of treatment. The aim of this study was to investigate the effects of illness and antipsychotic treatment on brain structures in antipsychotic-naïve first-episode schizophrenia based on a longitudinal short-term design. Twenty antipsychotic-naïve subjects with first-episode schizophrenia and twenty-four age- and sex-matched healthy controls underwent 3T MRI scans. Voxel-based morphometry (VBM) was used to examine the brain structural abnormality in patients compared to healthy controls. Nine patients were included in the follow-up examination after 8 weeks of treatment. Tensor-based morphometry (TBM) was used to identify longitudinal brain structural changes. We observed significantly reduced grey matter volume in the right superior temporal gyrus in antipsychotic-naïve patients with schizophrenia compared with healthy controls. After 8 weeks of treatment, patients showed significantly increased grey matter volume primarily in the bilateral prefrontal cortex, insula, right thalamus, left superior occipital cortex and the bilateral cerebellum. In addition, a greater enlargement of the prefrontal cortex is associated with the improvement in negative symptoms, and a more enlarged thalamus is associated with greater improvement in positive symptoms. Our results suggest the following: (1) the abnormality in the right superior temporal gyrus is present in the early stages of schizophrenia, possibly representing the core region related to schizophrenia; and (2) atypical antipsychotics could modulate brain morphology involving the thalamus, cortical grey matter and cerebellum. In addition, examination of the prefrontal cortex and thalamus might facilitate an efficient response to atypical antipsychotics in terms of symptom improvement. PMID:26789520

  18. Effects of Methylphenidate on Resting-State Functional Connectivity of the Mesocorticolimbic Dopamine Pathways in Cocaine Addiction

    PubMed Central

    Konova, Anna B.; Moeller, Scott J.; Tomasi, Dardo; Volkow, Nora D.; Goldstein, Rita Z.

    2015-01-01

    Importance Cocaine addiction is associated with altered resting-state functional connectivity among regions of the mesocorticolimbic dopamine pathways. Methylphenidate hydrochloride, an indirect dopamine agonist, normalizes task-related regional brain activity and associated behavior in cocaine users; however, the neural systems–level effects of methylphenidate in this population have not yet been described. Objective To use resting-state functional magnetic resonance imaging to examine changes in mesocorticolimbic connectivity with methylphenidate and how connectivity of affected pathways relates to severity of cocaine addiction. Design Randomized, placebo-controlled, before-after, crossover study. Setting Clinical research center. Participants Eighteen nonabstaining individuals with cocaine use disorders. Interventions Single doses of oral methylphenidate (20 mg) or placebo were administered at each of 2 study sessions. At each session, resting scans were acquired twice: immediately after drug administration (before the onset of effects [baseline]) and 120 minutes later (within the window of peak effects). Main outcomes and Measures Functional connectivity strength was evaluated using a seed voxel correlation approach. Changes in this measure were examined to characterize the neural systems–level effects of methylphenidate; severity of cocaine addiction was assessed by interview and questionnaire. Results Short-term methylphenidate administration reduced an abnormally strong connectivity of the ventral striatum with the dorsal striatum (putamen/globus pallidus), and lower connectivity between these regions during placebo administration uniquely correlated with less severe addiction. In contrast, methylphenidate strengthened several corticolimbic and corticocortical connections. Conclusions and Relevance These findings help elucidate the neural systems–level effects of methylphenidate and suggest that short-term methylphenidate can, at least transiently

  19. Connecting Homework Effectiveness with Montessori Practice

    ERIC Educational Resources Information Center

    Bagby, Janet; Sulak, Tracey

    2015-01-01

    This article examines recent educational research on the effectiveness of homework in improving achievement. The definition we have chosen to use for homework is any assignment intended to be completed during nonschool hours.

  20. Different effects of abnormal activation and myocardial disease on left ventricular ejection and filling times

    PubMed Central

    Zhou, Q; Henein, M; Coats, A; Gibson, D

    2000-01-01

    BACKGROUND—Ventricular activation is often abnormal in patients with dilated cardiomyopathy, but its specific effects on timing remain undetermined.
OBJECTIVE—To investigate the use of the ratio of the sum of left ventricular ejection and filling times to the total RR interval (Z ratio) to dissociate the effects of abnormal activation from those of cavity dilatation.
METHODS—Subjects were 20 normal individuals, 11 patients with isolated left bundle branch block (LBBB, QRS duration > 120 ms), 17 with dilated cardiomyopathy and normal activation, and 23 with dilated cardiomyopathy and LBBB. An additional 30 patients (nine with normal ventricular systolic function and 21 with dilated cardiomyopathy) were studied before and after right ventricular pacing. Left ventricular ejection and filling times were measured by pulsed wave Doppler and cavity size by M mode echocardiography.
RESULTS—Z ratio was independent of RR interval in all groups. Mean (SD) Z ratio was 82 (10)% for normal subjects, 66 (10)% for isolated LBBB (p < 0.01 v normal), 77 (7)% for dilated cardiomyopathy without LBBB (NS v normal), and 61 (7)% for dilated cardiomyopathy with LBBB (p < 0.01 v normal). In the nine patients with normal left ventricular size and QRS duration, Z ratio fell from 88 (6)% in sinus rhythm to 77 (10)% with right ventricular pacing (p = 0.26). In the 21 patients with dilated cardiomyopathy and LBBB, Z ratio rose from 59 (10)% in sinus rhythm to 74 (9)% with right ventricular DDD pacing (p < 0.001).
CONCLUSIONS—Z ratio dissociates the effects of abnormal ventricular activation and systolic disease. It also clearly differentiates right ventricular pacing from LBBB. It may thus be useful in comparing the haemodynamic effects of different pacing modes in patients with or without left ventricular disease.


Keywords: dilated cardiomyopathy; pacemaker; left bundle branch block; echocardiography. PMID:10956289

  1. The "Mozart Effect" and the Mathematical Connection

    ERIC Educational Resources Information Center

    Taylor, Judy M.; Rowe, Beverly J.

    2012-01-01

    Educators are always looking for ways to enhance the performance of students on outcome assessments. There is a growing body of research showing the benefits of music on educational performance. The purpose of this study was to determine if a "Mozart Effect" improves student performance on outcome assessments in mathematics. In this study, during…

  2. Confounding effects of indirect connections on causality estimation.

    PubMed

    Vakorin, Vasily A; Krakovska, Olga A; McIntosh, Anthony R

    2009-10-30

    Addressing the issue of effective connectivity, this study focuses on effects of indirect connections on inferring stable causal relations: partial transfer entropy. We introduce a Granger causality measure based on a multivariate version of transfer entropy. The statistic takes into account the influence of the rest of the network (environment) on observed coupling between two given nodes. This formalism allows us to quantify, for a specific pathway, the total amount of indirect coupling mediated by the environment. We show that partial transfer entropy is a more sensitive technique to identify robust causal relations than its bivariate equivalent. In addition, we demonstrate the confounding effects of the variation in indirect coupling on the detectability of robust causal links. Finally, we consider the problem of model misspecification and its effect on the robustness of the observed connectivity patterns, showing that misspecifying the model may be an issue even for model-free information-theoretic approach. PMID:19628006

  3. Handedness and effective connectivity of the motor system

    PubMed Central

    Pool, Eva-Maria; Rehme, Anne K.; Fink, Gereon R.; Eickhoff, Simon B.; Grefkes, Christian

    2016-01-01

    Handedness denotes the individual predisposition to consistently use the left or right hand for most types of skilled movements. A putative neurobiological mechanism for handedness consists in hemisphere-specific differences in network dynamics that govern unimanual movements. We, therefore, used functional magnetic resonance imaging and dynamic causal modeling to investigate effective connectivity between key motor areas during fist closures of the dominant or non-dominant hand performed by 18 right- and 18 left-handers. Handedness was assessed employing the Edinburgh-Handedness-Inventory (EHI). The network of interest consisted of key motor regions in both hemispheres including the primary motor cortex (M1), supplementary motor area (SMA), ventral premotor cortex (PMv), motor putamen (Put) and motor cerebellum (Cb). The connectivity analysis revealed that in right-handed subjects movements of the dominant hand were associated with significantly stronger coupling of contralateral (left, i.e., dominant) SMA with ipsilateral SMA, ipsilateral PMv, contralateral motor putamen and contralateral M1 compared to equivalent connections in left-handers. The degree of handedness as indexed by the individual EHI scores also correlated with coupling parameters of these connections. In contrast, we found no differences between right- and left-handers when testing for the effect of movement speed on effective connectivity. In conclusion, the data show that handedness is associated with differences in effective connectivity within the human motor network with a prominent role of SMA in right-handers. Left-handers featured less asymmetry in effective connectivity implying different hemispheric mechanisms underlying hand motor control compared to right-handers. PMID:24862079

  4. Matrix method analysis of quantum Hall effect device connections

    NASA Astrophysics Data System (ADS)

    Ortolano, M.; Callegaro, L.

    2012-02-01

    The modelling of electrical connections of single, or several, multiterminal quantum Hall effect (QHE) devices is relevant for electrical metrology: it is known, in fact, that certain particular connections allow (i) the realization of multiples or fractions of the quantized resistance, or (ii) the rejection of stray impedances, so that the configuration maintains the status of quantum standard. Ricketts-Kemeny and Delahaye equivalent circuits are known to be accurate models of the QHE: however, the numerical or analytical solution of electrical networks including these equivalent circuits can be difficult. In this paper, we introduce a method of analysis based on the representation of a QHE device by means of the indefinite admittance matrix: external connections are then represented with another matrix, easily written by inspection. Some examples, including the solution of double- and triple-series connections, are shown.

  5. Altered functional and effective connectivity in anticorrelated intrinsic networks in children with benign childhood epilepsy with centrotemporal spikes

    PubMed Central

    Luo, Cheng; Yang, Fei; Deng, Jiayan; Zhang, Yaodan; Hou, Changyue; Huang, Yue; Cao, Weifang; Wang, Jianjun; Xiao, Ruhui; Zeng, Nanlin; Wang, Xiaoming; Yao, Dezhong

    2016-01-01

    Abstract There are 2 intrinsic networks in the human brain: the task positive network (TPN) and task negative network (alternately termed the default mode network, DMN) in which inverse correlations have been observed during resting state and event-related functional magnetic resonance imaging (fMRI). The antagonism between the 2 networks might indicate a dynamic interaction in the brain that is associated with development. To evaluate the alterations in the relations of the 2 networks in children with benign childhood epilepsy with centrotemporal spikes (BECTS), resting state fMRI was performed in 17 patients with BECTS and 17 healthy controls. The functional and effective connectivities of 29 nodes in the TPN and DMN were analyzed. Positive functional connectivity (FC) within the networks and negative FC between the 2 networks were observed in both groups. The patients exhibited increased FC within both networks, particularly in the frontoparietal nodes such as the left superior frontal cortex, and enhanced antagonism between the 2 networks, suggesting abnormal functional integration of the nodes of the 2 networks in the patients. Granger causality analysis revealed a significant difference in the degree of outflow to inflow in the left superior frontal cortex and the left ventral occipital lobe. The alterations observed in the combined functional and effective connectivity analyses might indicate an association of an abnormal ability to integrate information between the DMN and TPN and the epileptic neuropathology of BECTS and provide preliminary evidence supporting the occurrence of abnormal development in children with BECTS. PMID:27310959

  6. Effective glued connection between multimode polymer and silica optical fibers

    NASA Astrophysics Data System (ADS)

    Wonko, R.; Pura-Pawlikowska, P.; Marć, P.; Chruściel, M.; Jaroszewicz, L. R.

    2015-12-01

    This paper presents the technology of performing an effective glued connection between optical fibers made from silica (SOF) and polymer (POF) and a pair of polymer optical fibers (POF-POF). This study has been undertaken in order to establish the influence of cleaving for quality of fiber preparation (its cutting in particular), type of glue, as well as joint spot protection. The prototype of a hot cleaver of POF, made in Institute of Applied Physics MUT, was minimalized and adapted to a single use of blade. Matching geometry of connected structures was optimized by adjusting optical fibers to each other. The result of this research was to define particular distance between fibers. It turned out that the optimized distance amounts to 30 μm. Experiment showed that a joint made of optical glue has given loss of less than 0.2 dB. The next step was to involve protection of the mechanical joint. It turned out that glass capillary complies with the requirements. In order to confirm the effectiveness of the chosen glue connection, measurements of technical parameters on patch cords with MMF - POF and POF - POF connections were made. It was stated that SOF - POF connections can work within the range of -40°C + 60°C workable for humidity simulation without loss change. However, connections POF - POF are unstable with respect to temperature change. Modal characteristics of near- field were also observed.

  7. The spectrum of echocardiographic abnormalities in hypothyroidism and the effect of hormonal treatment.

    PubMed

    Nouh, M S; Famuyiwa, O O; Sulimani, R A; Al-Nuaim, A

    1991-11-01

    Cross-sectional echocardiography was used to identify and quantify different cardiac abnormalities in 85 patients with hypothyroidism. Pericardial effusion was the most common and was found in 32 patients (37.6%), while abnormal increase in left ventricular dimensions with impairment of function followed next in frequency (16.4%). Asymmetrical septal hypertrophy as well as segmental wall motion abnormality were each detected in 11.76%. Holosystolic prolapse of the mitral valve was present in only 4.7% of the cases. Different combinations of abnormalities were observed in a total of 22 patients (25.76%), and pericardial effusion was a constant finding. Some of the abnormalities were reversed with physiological thyroxin replacement, but abnormal wall motion remained unimproved. PMID:17590809

  8. Altered effective connectivity of default model brain network underlying amnestic MCI

    NASA Astrophysics Data System (ADS)

    Yan, Hao; Wang, Yonghui; Tian, Jie

    2012-02-01

    Mild cognitive impairment (MCI) is the transitional, heterogeneous continuum from healthy elderly to Alzheimer's disease (AD). Previous studies have shown that brain functional activity in the default mode network (DMN) is impaired in MCI patients. However, the altered effective connectivity of the DMN in MCI patients remains largely unknown. The present study combined an independent component analysis (ICA) approach with Granger causality analysis (mGCA) to investigate the effective connectivity within the DMN in 12 amnestic MCI patients and 12 age-matched healthy elderly. Compared to the healthy control, the MCI exhibited decreased functional activity in the posterior DMN regions, as well as a trend towards activity increases in anterior DMN regions. Results from mGCA further supported this conclusion that the causal influence projecting to the precuneus/PCC became much weaker in MCI, while stronger interregional interactions emerged within the frontal-parietal cortices. These findings suggested that abnormal effective connectivity within the DMN may elucidate the dysfunctional and compensatory processes in MCI brain networks.

  9. Developmental changes in effective connectivity associated with relational reasoning.

    PubMed

    Bazargani, Narges; Hillebrandt, Hauke; Christoff, Kalina; Dumontheil, Iroise

    2014-07-01

    Rostrolateral prefrontal cortex (RLPFC) is part of a frontoparietal network of regions involved in relational reasoning, the mental process of working with relationships between multiple mental representations. RLPFC has shown functional and structural changes with age, with increasing specificity of left RLPFC activation for relational integration during development. Here, we used dynamic causal modeling (DCM) to investigate changes in effective connectivity during a relational reasoning task through the transition from adolescence into adulthood. We examined fMRI data of 37 healthy female participants (11–30 years old) performing a relational reasoning paradigm. Comparing relational integration to the manipulation of single relations revealed activation in five regions: the RLPFC, anterior insula, dorsolateral PFC, inferior parietal lobe, and medial superior frontal gyrus. We used a new exhaustive search approach and identified a full DCM model, which included all reciprocal connections between the five clusters in the left hemisphere, as the optimal model. In line with previous resting state fMRI results, we showed distinct developmental effects on the strength of long-range frontoparietal versus frontoinsular short-range fixed connections. The modulatory connections associated with relational integration increased with age. Gray matter volume in left RLPFC, which decreased with age, partly accounted for changes in fixed PFC connectivity. Finally, improvements in relational integration performance were associated with greater modulatory and weaker fixed PFC connectivity. This pattern provides further evidence of increasing specificity of left PFC function for relational integration compared to the manipulation of single relations, and demonstrates an association between effective connectivity and performance during development. PMID:25050424

  10. Meiotic abnormalities

    SciTech Connect

    1993-12-31

    Chapter 19, describes meiotic abnormalities. These include nondisjunction of autosomes and sex chromosomes, genetic and environmental causes of nondisjunction, misdivision of the centromere, chromosomally abnormal human sperm, male infertility, parental age, and origin of diploid gametes. 57 refs., 2 figs., 1 tab.

  11. Metabolic connectivity mapping reveals effective connectivity in the resting human brain.

    PubMed

    Riedl, Valentin; Utz, Lukas; Castrillón, Gabriel; Grimmer, Timo; Rauschecker, Josef P; Ploner, Markus; Friston, Karl J; Drzezga, Alexander; Sorg, Christian

    2016-01-12

    Directionality of signaling among brain regions provides essential information about human cognition and disease states. Assessing such effective connectivity (EC) across brain states using functional magnetic resonance imaging (fMRI) alone has proven difficult, however. We propose a novel measure of EC, termed metabolic connectivity mapping (MCM), that integrates undirected functional connectivity (FC) with local energy metabolism from fMRI and positron emission tomography (PET) data acquired simultaneously. This method is based on the concept that most energy required for neuronal communication is consumed postsynaptically, i.e., at the target neurons. We investigated MCM and possible changes in EC within the physiological range using "eyes open" versus "eyes closed" conditions in healthy subjects. Independent of condition, MCM reliably detected stable and bidirectional communication between early and higher visual regions. Moreover, we found stable top-down signaling from a frontoparietal network including frontal eye fields. In contrast, we found additional top-down signaling from all major clusters of the salience network to early visual cortex only in the eyes open condition. MCM revealed consistent bidirectional and unidirectional signaling across the entire cortex, along with prominent changes in network interactions across two simple brain states. We propose MCM as a novel approach for inferring EC from neuronal energy metabolism that is ideally suited to study signaling hierarchies in the brain and their defects in brain disorders. PMID:26712010

  12. Metabolic connectivity mapping reveals effective connectivity in the resting human brain

    PubMed Central

    Riedl, Valentin; Utz, Lukas; Castrillón, Gabriel; Grimmer, Timo; Rauschecker, Josef P.; Drzezga, Alexander; Sorg, Christian

    2016-01-01

    Directionality of signaling among brain regions provides essential information about human cognition and disease states. Assessing such effective connectivity (EC) across brain states using functional magnetic resonance imaging (fMRI) alone has proven difficult, however. We propose a novel measure of EC, termed metabolic connectivity mapping (MCM), that integrates undirected functional connectivity (FC) with local energy metabolism from fMRI and positron emission tomography (PET) data acquired simultaneously. This method is based on the concept that most energy required for neuronal communication is consumed postsynaptically, i.e., at the target neurons. We investigated MCM and possible changes in EC within the physiological range using “eyes open” versus “eyes closed” conditions in healthy subjects. Independent of condition, MCM reliably detected stable and bidirectional communication between early and higher visual regions. Moreover, we found stable top-down signaling from a frontoparietal network including frontal eye fields. In contrast, we found additional top-down signaling from all major clusters of the salience network to early visual cortex only in the eyes open condition. MCM revealed consistent bidirectional and unidirectional signaling across the entire cortex, along with prominent changes in network interactions across two simple brain states. We propose MCM as a novel approach for inferring EC from neuronal energy metabolism that is ideally suited to study signaling hierarchies in the brain and their defects in brain disorders. PMID:26712010

  13. The Effects of Grain Size and Texture on Dynamic Abnormal Grain Growth in Mo

    NASA Astrophysics Data System (ADS)

    Noell, Philip J.; Taleff, Eric M.

    2016-07-01

    This is the first report of abnormal grain morphologies specific to a Mo sheet material produced from a commercial-purity arc-melted ingot. Abnormal grains initiated and grew during plastic deformation of this material at temperatures of 1793 K and 1813 K (1520 °C and 1540 °C). This abnormal grain growth during high-temperature plastic deformation is termed dynamic abnormal grain growth, DAGG. DAGG in this material readily consumes nearly all grains near the sheet center while leaving many grains near the sheet surface unconsumed. Crystallographic texture, grain size, and other microstructural features are characterized. After recrystallization, a significant through-thickness variation in crystallographic texture exists in this material but does not appear to directly influence DAGG propagation. Instead, dynamic normal grain growth, which may be influenced by texture, preferentially occurs near the sheet surface prior to DAGG. The large grains thus produced near the sheet surface inhibit the subsequent growth of the abnormal grains produced by DAGG, which preferentially consume the finer grains near the sheet center. This produces abnormal grains that span the sheet center but leave unconsumed polycrystalline microstructure near the sheet surface. Abnormal grains are preferentially oriented with the < 110rangle approximately along the tensile axis. These results provide additional new evidence that boundary curvature is the primary driving force for DAGG in Mo.

  14. Altered resting-state EEG source functional connectivity in schizophrenia: the effect of illness duration

    PubMed Central

    Di Lorenzo, Giorgio; Daverio, Andrea; Ferrentino, Fabiola; Santarnecchi, Emiliano; Ciabattini, Fabio; Monaco, Leonardo; Lisi, Giulia; Barone, Ylenia; Di Lorenzo, Cherubino; Niolu, Cinzia; Seri, Stefano; Siracusano, Alberto

    2015-01-01

    Despite the increasing body of evidence supporting the hypothesis of schizophrenia as a disconnection syndrome, studies of resting-state EEG Source Functional Connectivity (EEG-SFC) in people affected by schizophrenia are sparse. The aim of the present study was to investigate resting-state EEG-SFC in 77 stable, medicated patients with schizophrenia (SCZ) compared to 78 healthy volunteers (HV). In order to study the effect of illness duration, SCZ were divided in those with a short duration of disease (SDD; n = 25) and those with a long duration of disease (LDD; n = 52). Resting-state EEG recordings in eyes closed condition were analyzed and lagged phase synchronization (LPS) indices were calculated for each ROI pair in the source-space EEG data. In delta and theta bands, SCZ had greater EEG-SFC than HV; a higher theta band connectivity in frontal regions was observed in LDD compared with SDD. In the alpha band, SCZ showed lower frontal EEG-SFC compared with HV whereas no differences were found between LDD and SDD. In the beta1 band, SCZ had greater EEG-SFC compared with HVs and in the beta2 band, LDD presented lower frontal and parieto-temporal EEG-SFC compared with HV. In the gamma band, SDD had greater connectivity values compared with LDD and HV. This study suggests that resting state brain network connectivity is abnormally organized in schizophrenia, with different patterns for the different EEG frequency components and that EEG can be a powerful tool to further elucidate the complexity of such disordered connectivity. PMID:25999835

  15. Behavioral, neurochemical and neuroendocrine effects of abnormal savda munziq in the chronic stress mice.

    PubMed

    Amat, Nurmuhammat; Hoxur, Parida; Ming, Dang; Matsidik, Aynur; Kijjoa, Anake; Upur, Halmurat

    2012-01-01

    Oral administration of Abnormal Savda Munsiq (ASMq), a herbal preparation used in Traditional Uighur Medicine, was found to exert a memory-enhancing effect in the chronic stressed mice, induced by electric foot-shock. The memory improvement of the stressed mice was shown by an increase of the latency time in the step-through test and the decrease of the latency time in the Y-maze test. Treatment with ASMq was found to significantly decrease the serum levels of adrenocorticotropic hormone (ACTH), corticosterone (CORT) and β-endorphin (β-EP) as well as the brain and serum level of norepinephrine (NE). Furthermore, ASMq was able to significantly reverse the chronic stress by decreasing the brain and serum levels of the monoamine neurotransmitters dopamine (DA), 5-hydroxytryptamine (5-HT) and 3,4-dihydroxyphenylalanine (DOPAC). The results obtained from this study suggested that the memory-enhancing effect of ASMq was mediated through regulations of neurochemical and neuroendocrine systems. PMID:22919413

  16. Strain-Dependent Effect of Macroautophagy on Abnormally Folded Prion Protein Degradation in Infected Neuronal Cells

    PubMed Central

    Ishibashi, Daisuke; Homma, Takujiro; Nakagaki, Takehiro; Fuse, Takayuki; Sano, Kazunori; Takatsuki, Hanae; Atarashi, Ryuichiro; Nishida, Noriyuki

    2015-01-01

    Prion diseases are neurodegenerative disorders caused by the accumulation of abnormal prion protein (PrPSc) in the central nervous system. With the aim of elucidating the mechanism underlying the accumulation and degradation of PrPSc, we investigated the role of autophagy in its degradation, using cultured cells stably infected with distinct prion strains. The effects of pharmacological compounds that inhibit or stimulate the cellular signal transduction pathways that mediate autophagy during PrPSc degradation were evaluated. The accumulation of PrPSc in cells persistently infected with the prion strain Fukuoka-1 (FK), derived from a patient with Gerstmann–Sträussler–Scheinker syndrome, was significantly increased in cultures treated with the macroautophagy inhibitor 3-methyladenine (3MA) but substantially reduced in those treated with the macroautophagy inducer rapamycin. The decrease in FK-derived PrPSc levels was mediated, at least in part, by the phosphatidylinositol 3-kinase/MEK signalling pathway. By contrast, neither rapamycin nor 3MA had any apparently effect on PrPSc from either the 22L or the Chandler strain, indicating that the degradation of PrPSc in host cells might be strain-dependent. PMID:26368533

  17. Attenuation effect of Abnormal Savda Munziq on liver and heart toxicity caused by chemotherapy in mice

    PubMed Central

    AIKEMU, AINIWAER; AMAT, NURMUHAMAT; YUSUP, ABDIRYIM; SHAN, LIANLIAN; QI, XINWEI; UPUR, HALMURAT

    2016-01-01

    Abnormal Savda Munziq (ASMq), an Uighur medicine formula commonly used in the treatment of cancer, has been speculated to possess antioxidative and antiproliferative effects, and to regulate immune activity. The present study was designed to systematically elucidate the toxicity-reducing activity of ASMq in mice undergoing combination chemotherapy with doxorubicin and 5-fluorouracil (5-FU). The mice were divided into normal (saline, 10 ml/kg) and doxorubicin + 5-FU groups (doxorubicin, 2.5 mg/kg; 5-FU, 10 mg/kg on alternate days). In addition, three groups received different doses of ASMq (2, 4 and 8 g/kg), in addition to doxorubicin (2.5 mg/kg) and 5-FU (10 mg/kg) treatment on alternate days. The histology of the heart and liver, superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) activity, malondialdehyde (MDA) concentrations in heart homogenate, and various biochemical parameters of the liver were evaluated. Compared with the normal control group, ASMq dose-dependently improved a number of variables, including body weight, liver index, transaminase and total protein, and partially normalized liver and cardiac pathology. ASMq restored activities of defense antioxidant enzymes SOD and GSH-Px towards normal levels, and decreased MDA concentration in dose-dependent manner. These results demonstrated that ASMq provides significant protection against doxorubicin + 5-FU combination induced hepatotoxicity and cardiotoxicity. Further studies are required to determine the effects of ASMq against doxorubicin + 5-FU-induced toxicity during chemotherapy in vivo. PMID:27347066

  18. Aging Effects on Whole-Brain Functional Connectivity in Adults Free of Cognitive and Psychiatric Disorders.

    PubMed

    Ferreira, Luiz Kobuti; Regina, Ana Carolina Brocanello; Kovacevic, Natasa; Martin, Maria da Graça Morais; Santos, Pedro Paim; Carneiro, Camila de Godoi; Kerr, Daniel Shikanai; Amaro, Edson; McIntosh, Anthony Randal; Busatto, Geraldo F

    2016-09-01

    Aging is associated with decreased resting-state functional connectivity (RSFC) within the default mode network (DMN), but most functional imaging studies have restricted the analysis to specific brain regions or networks, a strategy not appropriate to describe system-wide changes. Moreover, few investigations have employed operational psychiatric interviewing procedures to select participants; this is an important limitation since mental disorders are prevalent and underdiagnosed and can be associated with RSFC abnormalities. In this study, resting-state fMRI was acquired from 59 adults free of cognitive and psychiatric disorders according to standardized criteria and based on extensive neuropsychological and clinical assessments. We tested for associations between age and whole-brain RSFC using Partial Least Squares, a multivariate technique. We found that normal aging is not only characterized by decreased RSFC within the DMN but also by ubiquitous increases in internetwork positive correlations and focal internetwork losses of anticorrelations (involving mainly connections between the DMN and the attentional networks). Our results reinforce the notion that the aging brain undergoes a dedifferentiation processes with loss of functional diversity. These findings advance the characterization of healthy aging effects on RSFC and highlight the importance of adopting a broad, system-wide perspective to analyze brain connectivity. PMID:26315689

  19. Decreased effective connectivity in the visuomotor system after alcohol consumption.

    PubMed

    Luchtmann, Michael; Jachau, Katja; Adolf, Daniela; Baecke, Sebastian; Lützkendorf, Ralf; Müller, Charles; Tempelmann, Claus; Bernarding, Johannes

    2013-05-01

    Functional magnetic resonance imaging (fMRI) allows observing cerebral activity not only in separated cortical regions but also in functionally coupled cortical networks. Although moderate doses of ethanol slowdown the neurovascular coupling, the functions of the primary sensorimotor and the visual system remain intact. Yet little is known about how more complex interactions between cortical regions are affected even at moderate doses of alcohol. Therefore the method of psychophysiological interaction (PPI) was applied to analyze ethanol-induced effects on the effective connectivity in the visuomotor system. Fourteen healthy social drinkers with no personal history of neurological disorders or substance abuse were examined. In a test/re-test design they served as their own controls by participating in both the sober and the ethanol condition. All participants were scanned in a 3 T MR scanner before and after ingestion of a body-weight-dependent amount of ethanol calculated to achieve a blood alcohol concentration of 1.0‰. PPIs were calculated for the primary visual cortex, the supplementary motor area, and the left and right primary motor cortex using the statistical software package SPM. The PPI analysis showed selective disturbance of the effective connectivity between different cortical areas. The regression analysis revealed the influence of the supplementary motor area on connected regions like the primary motor cortex to be decreased yet preserved. However, the connection between the primary visual cortex and the posterior parietal cortex was more severely impaired by the influence of ethanol, leading to an uncoupled regression between these regions. The decreased effective connectivity in the visuomotor system suggests that complex tasks requiring interaction or synchronization between different brain areas are affected even at moderate levels of alcohol. This finding may have important consequences for determining which components of demanding tasks such

  20. Congenital Abnormalities

    MedlinePlus

    ... serious health problems (e.g. Down syndrome ). Single-Gene Abnormalities Sometimes the chromosomes are normal in number, ... blood flow to the fetus impair fetal growth. Alcohol consumption and certain drugs during pregnancy significantly increase ...

  1. Craniofacial Abnormalities

    MedlinePlus

    ... of the skull and face. Craniofacial abnormalities are birth defects of the face or head. Some, like cleft ... palate, are among the most common of all birth defects. Others are very rare. Most of them affect ...

  2. Walking abnormalities

    MedlinePlus

    ... include: Arthritis of the leg or foot joints Conversion disorder (a psychological disorder) Foot problems (such as a ... injuries. For an abnormal gait that occurs with conversion disorder, counseling and support from family members are strongly ...

  3. Chromosome Abnormalities

    MedlinePlus

    ... decade, newer techniques have been developed that allow scientists and doctors to screen for chromosomal abnormalities without using a microscope. These newer methods compare the patient's DNA to a normal DNA ...

  4. Nail abnormalities

    MedlinePlus

    Nail abnormalities are problems with the color, shape, texture, or thickness of the fingernails or toenails. ... Fungus or yeast cause changes in the color, texture, and shape of the nails. Bacterial infection may ...

  5. Estimation of effective connectivity via data-driven neural modeling

    PubMed Central

    Freestone, Dean R.; Karoly, Philippa J.; Nešić, Dragan; Aram, Parham; Cook, Mark J.; Grayden, David B.

    2014-01-01

    This research introduces a new method for functional brain imaging via a process of model inversion. By estimating parameters of a computational model, we are able to track effective connectivity and mean membrane potential dynamics that cannot be directly measured using electrophysiological measurements alone. The ability to track the hidden aspects of neurophysiology will have a profound impact on the way we understand and treat epilepsy. For example, under the assumption the model captures the key features of the cortical circuits of interest, the framework will provide insights into seizure initiation and termination on a patient-specific basis. It will enable investigation into the effect a particular drug has on specific neural populations and connectivity structures using minimally invasive measurements. The method is based on approximating brain networks using an interconnected neural population model. The neural population model is based on a neural mass model that describes the functional activity of the brain, capturing the mesoscopic biophysics and anatomical structure. The model is made subject-specific by estimating the strength of intra-cortical connections within a region and inter-cortical connections between regions using a novel Kalman filtering method. We demonstrate through simulation how the framework can be used to track the mechanisms involved in seizure initiation and termination. PMID:25506315

  6. Effects of expected-value information and display format on recognition of aircraft subsystem abnormalities

    NASA Technical Reports Server (NTRS)

    Palmer, Michael T.; Abbott, Kathy H.

    1994-01-01

    This study identifies improved methods to present system parameter information for detecting abnormal conditions and to identify system status. Two workstation experiments were conducted. The first experiment determined if including expected-value-range information in traditional parameter display formats affected subject performance. The second experiment determined if using a nontraditional parameter display format, which presented relative deviation from expected value, was better than traditional formats with expected-value ranges included. The inclusion of expected-value-range information onto traditional parameter formats was found to have essentially no effect. However, subjective results indicated support for including this information. The nontraditional column deviation parameter display format resulted in significantly fewer errors compared with traditional formats with expected-value-ranges included. In addition, error rates for the column deviation parameter display format remained stable as the scenario complexity increased, whereas error rates for the traditional parameter display formats with expected-value ranges increased. Subjective results also indicated that the subjects preferred this new format and thought that their performance was better with it. The column deviation parameter display format is recommended for display applications that require rapid recognition of out-of-tolerance conditions, especially for a large number of parameters.

  7. Cell phone radiation effects on cytogenetic abnormalities of oral mucosal cells.

    PubMed

    Daroit, Natália Batista; Visioli, Fernanda; Magnusson, Alessandra Selinger; Vieira, Geila Radunz; Rados, Pantelis Varvaki

    2015-01-01

    The aim of this study was to evaluate the effects of exposure to cell phone electromagnetic radiation on the frequency of micronuclei, broken eggs cells, binucleated cells, and karyorrhexis in epithelial cells of the oral mucosa. The sample was composed of 60 cell phone users, who were non-smokers and non-drinkers, and had no clinically visible oral lesions. Cells were obtained from anatomical sites with the highest incidence of oral cancer: lower lip, border of the tongue, and floor of the mouth. The Feulgen reaction was used for quantification of nuclear anomalies in 1,000 cells/slide. A slightly increase in the number of micronucleated cells in the lower lip and in binucleated cells on the floor of the mouth was observed in individuals who used their phones > 60 minutes/week. The analysis also revealed an increased number of broken eggs in the tongue of individuals owning a cell phone for over eight years. Results suggest that exposure to electromagnetic waves emitted by cell phones can increase nuclear abnormalities in individuals who use a cell phone for more than 60 minutes per week and for over eight years. Based on the present findings, we suggest that exposure to electromagnetic radiation emitted by cell phones may interfere with the development of metanuclear anomalies. Therefore, it is demonstrated that, despite a significant increase in these anomalies, the radiation emitted by cell phones among frequent users is within acceptable physiological limits. PMID:26486771

  8. Cancer, reproductive abnormalities, and diabetes in Micronesia: the effect of nuclear testing.

    PubMed

    Yamada, Seiji

    2004-09-01

    Many suggest that cancer and other diseases in Micronesia have been caused by nuclear testing in the Pacific. The 50-year commemoration of the March 1, 1954 Bravo thermonuclear test has rekindled interest in this area. This paper explores the documentation for, and the plausibility of, claims for disease causation by nuclear testing. Given the sheer volume of testing that the US conducted in the Pacific, it appears plausible that excess cancer would have occurred in areas of Micronesia other than the Marshall Islands. An excess of birth abnormalities in the Marshall Islands has been documented. While diabetes is not a radiogenic disease, and other cancers are generally less radiogenic than leukemia or thyroid cancer, the social and cultural effects of nuclear testing specifically, and the strategic uses to which Micronesia has been put generally, have had roles in the social production of disease. Integration into a globalized, cosmopolitan economy-with attendant phenomena such as the importation of tobacco, alcohol, foods of poor nutritional value, and new cultural morés-are also factors. PMID:16281703

  9. Protective Effects of Ginger (Zingiber officinale) Extract against Diabetes-Induced Heart Abnormality in Rats

    PubMed Central

    Ilkhanizadeh, Behrouz; Khadem Ansari, Mohamad hasan; Nemati, Samira; Rasmi, Yusef

    2016-01-01

    Background Diabetic cardiomyopathy is an important causal factor in morbidity and mortality among diabetic patients, and currently, no effective means are available to reverse its pathological progress. The purpose of the present study was to investigate the effect of ginger extract on apolipoproteins (apo) A and B, hyperhomocysteinemia, cathepsin G and leptin changes, as well as cardiac fibrosis and heart muscle cell proliferation under hyperglycemic conditions in vivo. Methods Twenty-four male Wistar rats were divided into three groups, namely: control, non-treated diabetic, and ginger extract-treated diabetic groups. The ginger extract-treated diabetic group received a 50 mg daily dose of ginger extract intragastrically for 6 weeks. Results The results revealed concurrent significant increases in plasma C-reactive protein (CRP), homocysteine (Hcy), cathepsin G and apoB levels and decreases in apoA and leptin levels in the non-treated diabetic group compared to the control group. Moreover, heart structural changes, including fibrosis and heart muscle cell proliferation, were observed in non-treated diabetic rats compared to the control rats. Significant amelioration of changes in the heart structure together with restoration of the elevated levels of Hcy and CRP, leptin, cathepsin G, and apoA and B were found in the ginger extract-treated diabetic group compared to the non-treated diabetic group. Conclusion The findings indicated that ginger extract significantly reduces heart structural abnormalities in diabetic rats and that these effects might be associated with improvements in serum apo, leptin, cathepsin G, and Hcy levels and with the antioxidant properties of ginger extract. PMID:26912155

  10. [Dysfunction of serotonergic systems in thiamine-deficient diet fed mice: effects of SSRI on abnormality induced by thiamine deficiency].

    PubMed

    Murata, Atsunobu; Nakagawasai, Osamu; Yamadera, Fumihiro; Oba, Akira; Wakui, Kenji; Arai, Yuichiro; Tadano, Takeshi

    2004-04-01

    Mice fed a thiamine deficient (TD) diet, showed some abnormal behaviors such as amnesia and mood abnormality. It is known that several neurons, especially marked in serotonergic neuron, are damaged in humans and rodents in the earlier phase of TD. The symptoms derived from dysfunction of serotonergic neurons are observed in Wernicke-Korsakoff patients (WKS)-derived TD, and it is known that fluvoxamine is effective for WKS. However, the mechanism of this dysfunction is still unclear. For that reason, we studied the relative mechanism between abnormal behaviors and selective dysfunction of serotonergic neurons in TD animals. As a result, this dysfunction by TD is much affected by the brainstem region. But the effect of fluvoxamine on depressive symptoms in WKS patients is not reported; therefore we also studied the effects of fluvoxamine on the depressive behaviors in TD mice as a model of WKS. The increase of immobility time in a forced swimming test as depressive behavior in TD mice was significantly inhibited by fluvoxamine, suggesting an improvable effect on depressive symptoms. With those results of ours, the possible mechanisms between the abnormal behaviors derived from the dysfunction of serotonergic neurons and the role of serotonin in TD and WKS are reviewed here. PMID:15164618

  11. Spatial connectivity of urban clusters and regional climate effects

    NASA Astrophysics Data System (ADS)

    Jia, G.; Hu, Y.; Xu, R.

    2015-12-01

    Rapid urbanization in East Asia in past three decades is considered as a remarkable process that featured with expansion of urban clusters and tightened linkages within and among clusters. Such process could lead to much larger scale climate effects, and could even contribute to sub-regional and regional climate change. In large area of urban clusters with significant expansion of built-up in relatively short period, local urban heat islands could contribute to sub-regional climate forcing. Here we use visible/near infrared and thermal infrared satellite data to estimate multiple scale structure of urban clusters, and to assess effects of urban heat islands at local and regional scales in East Asia. Our estimates of urban extent were greater than previously reported in most global datasets. Strong spatial connection and internal expansion were found in major urban clusters in past 30 years, and was accelerated in past 10 years. Many city clusters were merging into each other, with gradual blurring boundaries and disappearing of gaps among member cities. Cities and towns were more connected with roads and commercial corridors, while wildland and urban greens became more isolated as patches among built-up areas. We would argue that in many cases in this region, urban clusters are no longer "islands", they are now "seas" in term of climate related urban canopy. Urban greens such as parks and plantation were long recognized for their cooling effects that buffer the urban heat island effect, however, such cooling effects tend to be weakened as their patches became smaller and isolated, and over dominated by urban surfaces. There were significant positive relations between urban fraction and urban heat island effects as demonstrated by VNIR and TIR data from multiple satellites. Those new estimates are expected to effectively improve climate simulation for better understanding the impacts of inter-connected urban clusters on air temperature, precipitation, wind speed

  12. Therapeutic effects of anti-spastic medication on neuromuscular abnormalities in SCI: a system identification approach.

    PubMed

    Mirbagheri, M M; Kindig, M; Niu, X; Varoqui, D

    2013-01-01

    Previous attempts to investigate the effects of antispastic medications are limited to clinical studies using that use clinical evaluations to assess. Since these measures are neither objective nor quantitative, the therapeutic effects of such medications on neuromuscular properties have not been fully evaluated. In this study, as a first attempt, we examined the effect of tizanidine, an anti-spastic medication, on modification of the neuromuscular properties of patients with chronic incomplete spinal cord injury (SCI). Each patient was administered 2 mg of tizanidine four times per day for four weeks. The spastic ankle of each patient was evaluated at baseline (prior to any medication, and then 1, 2, and 4 weeks after the start of medication. The ankle was perturbed with a small-amplitude Pseudo-Random Binary Sequence (PRBS) perturbation at various positions over the ankle range-of-motion. A parallel-cascade system identification technique, which provides an objective and quantitative measure of neuromuscular properties, was used to calculate the intrinsic and reflex stiffness. The stiffness vs. joint angle trends were then calculated for each evaluation; these curves were compared across the intervention time to determine the recovery pattern (i.e. change over time) due to the tizanidine intervention. All patients exhibited decreases in reflex stiffness (which abnormally increase after SCI) due to the medication; however, patients were observed to exhibit multiple recovery patterns. For some patients, the reflex stiffness continuously reduced over the four-week intervention period, while for other patients, the decrease during the first week (i.e. between the baseline and 1-Week evaluations) was most pronounced. Also, some patients presented a significant decrease with time, while others presented no improvement in the intrinsic stiffness. These findings suggest that tizanidine may be effective in reducing not only reflex stiffness, but also the subject

  13. Larval connectivity in an effective network of marine protected areas.

    PubMed

    Christie, Mark R; Tissot, Brian N; Albins, Mark A; Beets, James P; Jia, Yanli; Ortiz, Delisse M; Thompson, Stephen E; Hixon, Mark A

    2010-01-01

    Acceptance of marine protected areas (MPAs) as fishery and conservation tools has been hampered by lack of direct evidence that MPAs successfully seed unprotected areas with larvae of targeted species. For the first time, we present direct evidence of large-scale population connectivity within an existing and effective network of MPAs. A new parentage analysis identified four parent-offspring pairs from a large, exploited population of the coral-reef fish Zebrasoma flavescens in Hawai'i, revealing larval dispersal distances ranging from 15 to 184 km. In two cases, successful dispersal was from an MPA to unprotected sites. Given high adult abundances, the documentation of any parent-offspring pairs demonstrates that ecologically-relevant larval connectivity between reefs is substantial. All offspring settled at sites to the north of where they were spawned. Satellite altimetry and oceanographic models from relevant time periods indicated a cyclonic eddy that created prevailing northward currents between sites where parents and offspring were found. These findings empirically demonstrate the effectiveness of MPAs as useful conservation and management tools and further highlight the importance of coupling oceanographic, genetic, and ecological data to predict, validate and quantify larval connectivity among marine populations. PMID:21203576

  14. POLLUTION EFFECTS OF ABNORMAL OPERATIONS IN IRON AND STEEL MAKING. VOLUME 1. TECHNICAL REPORT

    EPA Science Inventory

    The report is the first in a six-volume series considering abnormal operating conditions (AOCs) in the primary section (sintering, blast furnace ironmaking, open hearth, electric furnace, and basic oxygen steelmaking) of an integrated iron and steel plant. Pollution standards, ge...

  15. POLLUTION EFFECTS OF ABNORMAL OPERATIONS IN IRON AND STEEL MAKING. VOLUME II. SINTERING, MANUAL OF PRACTICE

    EPA Science Inventory

    The report is one in a six-volume series considering abnormal operating conditions (AOCs) in the primary section (sintering, blast furnace ironmaking, open hearth, electric furnace, and basic oxygen steelmaking) of an integrated iron and steel plant. Pollution standards, generall...

  16. Abnormal N400 word repetition effects in fragile X-associated tremor/ataxia syndrome

    PubMed Central

    Chan, Shiaohui; Wong, Ling M.; Schneider, Andrea; Seritan, Andreea; Niese, Adam; Yang, Jin-Chen; Laird, Kelsey; Teichholtz, Sara; Khan, Sara; Tassone, Flora; Hagerman, Randi

    2010-01-01

    Fragile X-associated tremor/ataxia syndrome, a neurodegenerative disorder associated with premutation alleles (55–200 CGG repeats) of the FMR1 gene, affects many carriers in late-life. Patients with fragile X-associated tremor/ataxia syndrome typically have cerebellar ataxia, intranuclear inclusions in neurons and astrocytes, as well as cognitive impairment. Dementia can also be present with cognitive deficits that are as severe as in Alzheimer’s disease, however frontosubcortical type impairment is more pronounced in fragile X-associated tremor/ataxia syndrome. We sought to characterize the P600 and N400 word repetition effects in patients with fragile X-associated tremor/ataxia syndrome, using an event-related potential word repetition paradigm with demonstrated sensitivity to very early Alzheimer’s disease. We hypothesized that the fragile X-associated tremor/ataxia syndrome-affected participants with poor declarative verbal memory would have pronounced abnormalities in the P600 repetition effect. In the event-related potential experiment, subjects performed a category decision task whilst an electroencephalogram was recorded. Auditory category statements were each followed by an associated visual target word (50% ‘congruous’ category exemplars, 50% ‘incongruous’ nouns). Two-thirds of the stimuli (category statement–target word pairs) were repeated, either at short-lag (∼10–40 s) or long-lag (∼100–140 s). The N400 and P600 amplitude data were submitted to split-plot analyses of variance. These analyses of variance showed a highly significant reduction of the N400 repetition effect (F = 22.5, P < 0.001), but not of the P600 repetition effect, in mild fragile X-associated tremor/ataxia syndrome (n = 32, mean age = 68.7, mean Mini-Mental State Examination score = 26.8). Patients with fragile X-associated tremor/ataxia syndrome had significantly smaller late positive amplitude (550–800 ms post-stimulus onset) to congruous words (P = 0

  17. Effectiveness of routine ultrasonography in detecting fetal structural abnormalities in a low risk population.

    PubMed Central

    Chitty, L S; Hunt, G H; Moore, J; Lobb, M O

    1991-01-01

    OBJECTIVE--To review the efficacy of routine prenatal ultrasonography for detecting fetal structural abnormalities. DESIGN--Retrospective study of the ultrasonographic findings and outcome of all pregnancies in women scanned in 1988-9. SETTING--Maternity ultrasonography department of a district general hospital. SUBJECTS--8785 fetuses. MAIN OUTCOME MEASURES--Correlation of prenatal ultrasonographic findings with outcome in the neonate. RESULTS--8733 babies were born during 1988-9, and 52 pregnancies were terminated after a fetal malformation was identified. 8432 (95%) of the fetuses were examined by ultrasonography in the second trimester. 130 fetuses (1.5%) were found to have an abnormality at birth or after termination of pregnancy, 125 of which had been examined in the second trimester. In 93 cases the abnormality was detected before 24 weeks (sensitivity 74.4%, 95% confidence interval to 66.7% to 82.1%. Two false positive diagnoses occurred, in both cases the pregnancies were not terminated and apparently normal infants were born. This gives a specificity of 99.98% (99.9% to 99.99%). The positive predictive value of ultrasonography in the second trimester was 97.9% (92.6% to 99.7%). Of the 125 abnormalities, 87 were lethal or severely disabling; 72 of the 87 were detected by the routine screening programme (sensitivity 82.8%, 73.2% to 90.0%). CONCLUSION--Routine fetal examination by ultrasonography in a low risk population detects many fetal structural abnormalities but can present several dilemmas in counselling. PMID:1747613

  18. Connectivity and Excluded Volume Effects in Polymeric Complex Coacervates

    NASA Astrophysics Data System (ADS)

    Sing, Charles; Radhakrishna, Mithun

    Oppositely-charged polyelectrolytes in salt solutions can undergo phase separation to form complex coacervates. This charge-driven phase behavior is the basis for emerging motifs in self-assembly. Traditional uses for coacervates are in food and personal care products, while applications in technologies for drug delivery and sensory materials are being developed. One of the primary theories driving understanding of complex coacervates is the Voorn-Overbeek (V-O) theory, which is a precursor to more sophisticated field theories. We present both theory and simulation that provides an alternate picture of coacervates, specifically addressing the limitations of V-O. Our theoretical approach is based on PRISM, which is a liquid-state theory that specifically accounts for connectivity. This is compared with Monte Carlo-based simulations, which likewise provide a molecular picture of coacervation. We demonstrate that a combination of connectivity-based correlations and excluded volume has a profound effect on coacervation phase behavior, suggesting that favorable comparison of V-O to experiment benefits from a cancellation of errors. The influence of connectivity on coacervate phase behavior hints at new opportunities for molecular-based design in electrostatically-driven self-assembly.

  19. Effects of flaxseed consumption on systemic inflammation and serum lipid profile in hemodialysis patients with lipid abnormalities.

    PubMed

    Khalatbari Soltani, Saman; Jamaluddin, Rosita; Tabibi, Hadi; Mohd Yusof, Barakatun Nisak; Atabak, Shahnaz; Loh, Su-Peng; Rahmani, Leila

    2013-04-01

    Inflammation and lipid abnormalities are two important risk factors for cardiovascular disease in hemodialysis (HD) patients. The present study was designed to investigate the effects of flaxseed consumption on systemic inflammation and serum lipid profile in HD patients with lipid abnormalities. This was an unblinded, randomized clinical trial. Thirty HD patients with dyslipidemia (triglyceride >200 mg/dL and/or high-density lipoprotein-cholesterol (HDL-C) <40 mg/dL) were randomly assigned to either a flaxseed or control group. Patients in the flaxseed group received 40 g/day ground flaxseed for 8 weeks, whereas patients in the control group received their usual diet, without any flaxseed. At baseline and at the end of week 8, 7 mL of blood was collected after a 12- to 14-hour fast and serum concentrations of triglyceride, total cholesterol, low-density lipoprotein-cholesterol (LDL-C), HDL-C, and C-reactive protein (CRP) were measured. Serum concentrations of triglyceride (P < 0.01), total cholesterol (P < 0.01), LDL-C (P < 0.01), and CRP (P < 0.05) decreased significantly in the flaxseed group at the end of week 8 compared with baseline, whereas serum HDL-C showed a significant increase (P < 0.01). These changes in the flaxseed group were significant in comparison with the control group. The study indicates that flaxseed consumption improves lipid abnormalities and reduces systemic inflammation in HD patients with lipid abnormalities. PMID:22998533

  20. Detection of abnormal resting-state networks in individual patients suffering from focal epilepsy: an initial step toward individual connectivity assessment

    PubMed Central

    Dansereau, Christian L.; Bellec, Pierre; Lee, Kangjoo; Pittau, Francesca; Gotman, Jean; Grova, Christophe

    2014-01-01

    The spatial coherence of spontaneous slow fluctuations in the blood-oxygen-level dependent (BOLD) signal at rest is routinely used to characterize the underlying resting-state networks (RSNs). Studies have demonstrated that these patterns are organized in space and highly reproducible from subject to subject. Moreover, RSNs reorganizations have been suggested in pathological conditions. Comparisons of RSNs organization have been performed between groups of subjects but have rarely been applied at the individual level, a step required for clinical application. Defining the notion of modularity as the organization of brain activity in stable networks, we propose Detection of Abnormal Networks in Individuals (DANI) to identify modularity changes at the individual level. The stability of each RSN was estimated using a spatial clustering method: Bootstrap Analysis of Stable Clusters (BASC) (Bellec et al., 2010). Our contributions consisted in (i) providing functional maps of the most stable cores of each networks and (ii) in detecting “abnormal” individual changes in networks organization when compared to a population of healthy controls. DANI was first evaluated using realistic simulated data, showing that focussing on a conservative core size (50% most stable regions) improved the sensitivity to detect modularity changes. DANI was then applied to resting state fMRI data of six patients with focal epilepsy who underwent multimodal assessment using simultaneous EEG/fMRI acquisition followed by surgery. Only patient with a seizure free outcome were selected and the resected area was identified using a post-operative MRI. DANI automatically detected abnormal changes in 5 out of 6 patients, with excellent sensitivity, showing for each of them at least one “abnormal” lateralized network closely related to the epileptic focus. For each patient, we also detected some distant networks as abnormal, suggesting some remote reorganization in the epileptic brain. PMID

  1. Mice That Lack Thrombospondin 2 Display Connective Tissue Abnormalities That Are Associated with Disordered Collagen Fibrillogenesis, an Increased Vascular Density, and a Bleeding Diathesis

    PubMed Central

    Kyriakides, Themis R.; Zhu, Yu-Hong; Smith, Lynne T.; Bain, Steven D.; Yang, Zhantao; Lin, Ming T.; Danielson, Keith G.; Iozzo, Renato V.; LaMarca, Mary; McKinney, Cindy E.; Ginns, Edward I.; Bornstein, Paul

    1998-01-01

    Thrombospondin (TSP) 2, and its close relative TSP1, are extracellular proteins whose functions are complex, poorly understood, and controversial. In an attempt to determine the function of TSP2, we disrupted the Thbs2 gene by homologous recombination in embryonic stem cells, and generated TSP2-null mice by blastocyst injection and appropriate breeding of mutant animals. Thbs2−/− mice were produced with the expected Mendelian frequency, appeared overtly normal, and were fertile. However, on closer examination, these mice displayed a wide variety of abnormalities. Collagen fiber patterns in skin were disordered, and abnormally large fibrils with irregular contours were observed by electron microscopy in both skin and tendon. As a functional correlate of these findings, the skin was fragile and had reduced tensile strength, and the tail was unusually flexible. Mutant skin fibroblasts were defective in attachment to a substratum. An increase in total density and in cortical thickness of long bones was documented by histology and quantitative computer tomography. Mutant mice also manifested an abnormal bleeding time, and histologic surveys of mouse tissues, stained with an antibody to von Willebrand factor, showed a significant increase in blood vessels. The basis for the unusual phenotype of the TSP2-null mouse could derive from the structural role that TSP2 might play in collagen fibrillogenesis in skin and tendon. However, it seems likely that some of the diverse manifestations of this genetic disorder result from the ability of TSP2 to modulate the cell surface properties of mesenchymal cells, and thus, to affect cell functions such as adhesion and migration. PMID:9442117

  2. Combined effects of malathion and nitrate on early growth, abnormalities, and mortality of wood frog (Rana sylvatica) tadpoles.

    PubMed

    Krishnamurthy, S V; Smith, G R

    2011-08-01

    Use of pesticides and other agro-chemicals adversely influence amphibians either directly by killing them or by inducing sublethal, chronic effects. Many studies have investigated the effect of mixtures of pesticides or fertilizers. We studied the combined effects of nitrate and malathion ([(dimethoxy phosphino thioyl] butanediotae) on the early growth, expression of abnormalities, and mortality of Wood Frog (Rana sylvatica) tadpoles in a laboratory experiment. Tadpoles were treated with factorial combinations of 0, 8, and 16 mg NO(3)-N l(-1) and 0, 250, 500, and 1,000 μg malathion l(-1) for a period of 14 days. Feeding behaviour, total length, mean tadpole mass, frequencies of abnormalities, and survivorship in each treatment were recorded. Malathion showed a significant negative influence on all parameters and strongly influenced the frequencies of morphological anomalies. In contrast, nitrate alone did not produce any significant effects on behavior, total length, tadpole mass, or the frequency of abnormalities during the experiment. Malathion and nitrate had an interactive effect on tadpole length and mass, but did not affect any other parameters. Our results suggest that exposure to malathion, even at relatively low concentrations can have serious negative consequences for Wood Frog tadpoles. In addition, our results also indicate that there was little synergistic interaction between malathion and nitrate exposure under laboratory conditions. PMID:21533775

  3. Differential Patterns of Abnormal Activity and Connectivity in the Amygdala-Prefrontal Circuitry in Bipolar-I and Bipolar-NOS Youth

    ERIC Educational Resources Information Center

    Ladouceur, Cecile D.; Farchione, Tiffany; Diwadkar, Vaibhav; Pruitt, Patrick; Radwan, Jacqueline; Axelson, David A.; Birmaher, Boris; Phillips, Mary L.

    2011-01-01

    Objective: The functioning of neural systems supporting emotion processing and regulation in youth with bipolar disorder not otherwise specified (BP-NOS) remains poorly understood. We sought to examine patterns of activity and connectivity in youth with BP-NOS relative to youth with bipolar disorder type I (BP-I) and healthy controls (HC). Method:…

  4. Representing connectivity: quantifying effective habitat availability based on area and connectivity for conservation status assessment and recovery

    PubMed Central

    Tumas, Hayley R.; Marsden, Brittany W.

    2014-01-01

    We apply a comprehensive suite of graph theoretic metrics to illustrate how landscape connectivity can be effectively incorporated into conservation status assessments and in setting conservation objectives. These metrics allow conservation practitioners to evaluate and quantify connectivity in terms of representation, resiliency, and redundancy and the approach can be applied in spite of incomplete knowledge of species-specific biology and dispersal processes. We demonstrate utility of the graph metrics by evaluating changes in distribution and connectivity that would result from implementing two conservation plans for three endangered plant species (Erigeron parishii, Acanthoscyphus parishii var. goodmaniana, and Eriogonum ovalifolium var. vineum) relative to connectivity under current conditions. Although distributions of the species differ from one another in terms of extent and specific location of occupied patches within the study landscape, the spatial scale of potential connectivity in existing networks were strikingly similar for Erigeron and Eriogonum, but differed for Acanthoscyphus. Specifically, patches of the first two species were more regularly distributed whereas subsets of patches of Acanthoscyphus were clustered into more isolated components. Reserves based on US Fish and Wildlife Service critical habitat designation would not greatly contribute to maintain connectivity; they include 83–91% of the extant occurrences and >92% of the aerial extent of each species. Effective connectivity remains within 10% of that in the whole network for all species. A Forest Service habitat management strategy excluded up to 40% of the occupied habitat of each species resulting in both range reductions and loss of occurrences from the central portions of each species’ distribution. Overall effective network connectivity was reduced to 62–74% of the full networks. The distance at which each CHMS network first became fully connected was reduced relative to the

  5. Representing connectivity: quantifying effective habitat availability based on area and connectivity for conservation status assessment and recovery.

    PubMed

    Neel, Maile; Tumas, Hayley R; Marsden, Brittany W

    2014-01-01

    We apply a comprehensive suite of graph theoretic metrics to illustrate how landscape connectivity can be effectively incorporated into conservation status assessments and in setting conservation objectives. These metrics allow conservation practitioners to evaluate and quantify connectivity in terms of representation, resiliency, and redundancy and the approach can be applied in spite of incomplete knowledge of species-specific biology and dispersal processes. We demonstrate utility of the graph metrics by evaluating changes in distribution and connectivity that would result from implementing two conservation plans for three endangered plant species (Erigeron parishii, Acanthoscyphus parishii var. goodmaniana, and Eriogonum ovalifolium var. vineum) relative to connectivity under current conditions. Although distributions of the species differ from one another in terms of extent and specific location of occupied patches within the study landscape, the spatial scale of potential connectivity in existing networks were strikingly similar for Erigeron and Eriogonum, but differed for Acanthoscyphus. Specifically, patches of the first two species were more regularly distributed whereas subsets of patches of Acanthoscyphus were clustered into more isolated components. Reserves based on US Fish and Wildlife Service critical habitat designation would not greatly contribute to maintain connectivity; they include 83-91% of the extant occurrences and >92% of the aerial extent of each species. Effective connectivity remains within 10% of that in the whole network for all species. A Forest Service habitat management strategy excluded up to 40% of the occupied habitat of each species resulting in both range reductions and loss of occurrences from the central portions of each species' distribution. Overall effective network connectivity was reduced to 62-74% of the full networks. The distance at which each CHMS network first became fully connected was reduced relative to the full

  6. Effect of Lycium bararum polysaccharides on methylmercury-induced abnormal differentiation of hippocampal stem cells

    PubMed Central

    Tian, Jian-Ying; Chen, Wei-Wei; Cui, Jing; Wang, Hao; Chao, Ci; Lu, Zhi-Yan; Bi, Yong-Yi

    2016-01-01

    The aim of the present study was to observe the effects of a general extract of Lycium bararum polysaccharides (LBPs) on methylmercury (MeHg)-induced damage in hippocampus neural stem cells (hNSCs). The hippocampal tissues of embryonic day 16 Sprague-Dawley rats were extracted for the isolation, purification and cloning of hNSCs. Following passage and proliferation for 10 days, the cells were allocated at random into the following groups: Control, LBPs, MeHg and MeHg + LBPs. MTT and microtubule-associated protein 2 (MAP-2)/glial fibrillary acidic protein/Hoechst immunofluorescence tests were performed to detect the differentiation and growth of hNSCs in the various groups. The differentiation rate of MeHg-treated hNSCs and the perimeter of MAP-2-positive neurons were 3.632±0.63% and 62.36±5.58 µm, respectively, significantly lower compared with the control group values of 6.500±0.81% and 166±8.16 µm (P<0.05). Furthermore, the differentiation rate and the perimeter of MAP-2-positive neurons in LBPs groups cells was 7.75±0.59% and 253.3±11.21 µm, respectively, significantly higher compared with the control group (P<0.05). The same parameters in the MeHg + LBPs group were 5.92±0.98% and 111.9±6.07 µm, respectively, significantly higher than the MeHg group (P<0.05). The astrocyte differentiation rates in the MeHg and MeHg + LBPs group were 41.19±2.14 and 34.58±1.70, respectively (P<0.05). These results suggest that LBPs may promote the generation and development of new neurons and inhibit the MeHg-induced abnormal differentiation of astrocytes. Thus, LBPs may be considered to be a potential new treatment for MeHg-induced neurotoxicity in hNSCs. PMID:27446261

  7. Microheterogeneity of antithrombin III: effect of single amino acid substitutions and relationship with functional abnormalities.

    PubMed

    De Stefano, V; Leone, G; Mastrangelo, S; Lane, D A; Girolami, A; de Moerloose, P; Sas, G; Abildgaard, U; Blajchman, M; Rodeghiero, F

    1994-02-01

    Microheterogeneity of antithrombin III (AT-III) was investigated by crossed immunoelectrofocusing (CIEF) on eleven molecular variants. A normal pattern was found in five variants while two different abnormal CIEF patterns were found in the other four and two variants, respectively. Point mutations causing a major pI change (exceeding 4.0) of the amino acid substituted lead to alterations in the overall microheterogeneity. The variants thus substituted share a first type of abnormal CIEF pattern with alterations throughout the pH range, regardless of the location of the mutation (reactive site and adjacent regions or heparin binding region). Minor amino acid pI changes in these regions do not alter the AT-III overall microheterogeneity, whatever the resulting functional defect. However, if the mutation is placed in the region around positions 404 or 429, then even minor changes of the amino acid pI seem able to alter the overall charge, leading to a second type of abnormal CIEF pattern with the main alteration at pH 4.8-4.6. Neuraminidase treatment leads to disappearance of microheterogeneity except for the variants with the Arg393 to Cys substitution. Addition of thrombin induces CIEF modifications specifically related to the functional defect. A normal formation of thrombin-antithrombin complexes induces a shift towards the more acid pH range, whereas in the variants substituted at the reactive site the CIEF pattern is substantially unaffected by thrombin; variants substituted at positions 382-384 show a maximal thrombin-induced increase of the isoforms at pI 4.8-4.6. Therefore mutant antithrombins with different functional abnormalities but sharing a common CIEF pattern were well distinguished.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8180341

  8. Effect of positive acceleration (+gz) on electrocardiogram of subjects with vasoregulatory abnormality.

    PubMed Central

    Khanna, P K; Balasubramanian, K V; Dham, S K; Rai, K; Hoon, R S

    1977-01-01

    ST-T wave changes in the electrocardiogram detected during routine examination and aggravated by erect posture, hyperventilation, and exercise in apparently healthy young individuals have been termed vasoregulatory abnormalities. No evidence of ischaemic heart disease has been found in such subjects. Ten young healthy air crew with vasoregulatory abnormalities were subjected to maximal exercise on treadmill and procedure repeated after 120 mg propranolol daily for 3 days. After one week, they were subjected to a stress of positive acceleration (+gz) in a human centrifuge at 2-5 g and 3-5 g for 15 seconds each at a constant rate of rise of 0-1 g/s and the electrocardiogram was monitored during and in the post-acceleration phase. The procedure was repeated after propranolol 120 mg daily for 3 days. The stress of positive acceleration resulted in pronounced prominence of P waves and inversion of T waves (as has been reported in normal subjects) with minimal ST depression in the electrocardiogram. ST segment depression during exercise, at heart rates corresponding to those achieved during peak centrifuge runs, was significantly more pronounced. The ST, P, and T wave changes were returned to normal after propranolol. It is concluded that minimal ST segment depression after stress of positive acceleration as compared with conspicuous ST segment depression during exercise at corresponding heart rates, and their normalisation after propranolol, rules out ischaemia as an aetiological factor in subjects with vasoregulatory abnormalities. Images PMID:849393

  9. Abnormal, affect-specific modulatory effects on early auditory processing in schizophrenia: magnetoencephalographic evidence.

    PubMed

    Junghöfer, Markus; Bröckelmann, Ann-Kathrin; Küppers, Kerstin; Ohrmann, Patricia; Pedersen, Anya

    2015-02-01

    Abnormalities in the perception and identification of emotions have frequently been reported in schizophrenia. Hemodynamic neuroimaging studies found functional abnormalities in cortical and subcortical brain circuits that are involved in normal affective processing, but the temporal dynamics of abnormal emotion processing in schizophrenia remain largely elusive. To investigate this issue, we recorded early auditory evoked field components by means of whole-head magnetoencephalography that were in response to emotion-associated tones in seventeen patients with schizophrenia and in seventeen healthy, matched controls. Forty-two click-like tones (conditioned stimuli; CS) acquired differential emotional meaning through an affective associative learning procedure by pairing each CS three times with either pleasant, unpleasant or neutral auditory scenes. As expected, differential affect-specific modulation in patients vs. controls was evident, starting at the auditory N1m onset latency of approximately 70ms, extending to 230ms. While controls showed the expected enhanced processing of emotion associated CS, patients revealed an inverted pattern with reduced processing of arousal, when compared to neutral stimuli, in the right prefrontal cortex. The present finding suggests impairments in the prioritization of emotionally salient vs. non-salient stimuli in patients with schizophrenia. Dysfunction in higher cognitive processes and behavior in schizophrenia may therefore reflect dysfunction in fundamental, early emotion processing stages. PMID:25497223

  10. Estimation of Directed Effective Connectivity from fMRI Functional Connectivity Hints at Asymmetries of Cortical Connectome

    PubMed Central

    Gilson, Matthieu; Moreno-Bote, Ruben; Ponce-Alvarez, Adrián; Ritter, Petra; Deco, Gustavo

    2016-01-01

    The brain exhibits complex spatio-temporal patterns of activity. This phenomenon is governed by an interplay between the internal neural dynamics of cortical areas and their connectivity. Uncovering this complex relationship has raised much interest, both for theory and the interpretation of experimental data (e.g., fMRI recordings) using dynamical models. Here we focus on the so-called inverse problem: the inference of network parameters in a cortical model to reproduce empirically observed activity. Although it has received a lot of interest, recovering directed connectivity for large networks has been rather unsuccessful so far. The present study specifically addresses this point for a noise-diffusion network model. We develop a Lyapunov optimization that iteratively tunes the network connectivity in order to reproduce second-order moments of the node activity, or functional connectivity. We show theoretically and numerically that the use of covariances with both zero and non-zero time shifts is the key to infer directed connectivity. The first main theoretical finding is that an accurate estimation of the underlying network connectivity requires that the time shift for covariances is matched with the time constant of the dynamical system. In addition to the network connectivity, we also adjust the intrinsic noise received by each network node. The framework is applied to experimental fMRI data recorded for subjects at rest. Diffusion-weighted MRI data provide an estimate of anatomical connections, which is incorporated to constrain the cortical model. The empirical covariance structure is reproduced faithfully, especially its temporal component (i.e., time-shifted covariances) in addition to the spatial component that is usually the focus of studies. We find that the cortical interactions, referred to as effective connectivity, in the tuned model are not reciprocal. In particular, hubs are either receptors or feeders: they do not exhibit both strong incoming

  11. Estimation of Directed Effective Connectivity from fMRI Functional Connectivity Hints at Asymmetries of Cortical Connectome.

    PubMed

    Gilson, Matthieu; Moreno-Bote, Ruben; Ponce-Alvarez, Adrián; Ritter, Petra; Deco, Gustavo

    2016-03-01

    The brain exhibits complex spatio-temporal patterns of activity. This phenomenon is governed by an interplay between the internal neural dynamics of cortical areas and their connectivity. Uncovering this complex relationship has raised much interest, both for theory and the interpretation of experimental data (e.g., fMRI recordings) using dynamical models. Here we focus on the so-called inverse problem: the inference of network parameters in a cortical model to reproduce empirically observed activity. Although it has received a lot of interest, recovering directed connectivity for large networks has been rather unsuccessful so far. The present study specifically addresses this point for a noise-diffusion network model. We develop a Lyapunov optimization that iteratively tunes the network connectivity in order to reproduce second-order moments of the node activity, or functional connectivity. We show theoretically and numerically that the use of covariances with both zero and non-zero time shifts is the key to infer directed connectivity. The first main theoretical finding is that an accurate estimation of the underlying network connectivity requires that the time shift for covariances is matched with the time constant of the dynamical system. In addition to the network connectivity, we also adjust the intrinsic noise received by each network node. The framework is applied to experimental fMRI data recorded for subjects at rest. Diffusion-weighted MRI data provide an estimate of anatomical connections, which is incorporated to constrain the cortical model. The empirical covariance structure is reproduced faithfully, especially its temporal component (i.e., time-shifted covariances) in addition to the spatial component that is usually the focus of studies. We find that the cortical interactions, referred to as effective connectivity, in the tuned model are not reciprocal. In particular, hubs are either receptors or feeders: they do not exhibit both strong incoming

  12. Abnormalities of Inter- and Intra-Hemispheric Functional Connectivity in Autism Spectrum Disorders: A Study Using the Autism Brain Imaging Data Exchange Database.

    PubMed

    Lee, Jung Min; Kyeong, Sunghyun; Kim, Eunjoo; Cheon, Keun-Ah

    2016-01-01

    Recently, the Autism Brain Imaging Data Exchange (ABIDE) project revealed decreased functional connectivity in individuals with Autism Spectrum Disorders (ASD) relative to the typically developing controls (TDCs). However, it is still questionable whether the source of functional under-connectivity in subjects with ASD is equally contributed by the ipsilateral and contralateral parts of the brain. In this study, we decomposed the inter- and intra-hemispheric regions and compared the functional connectivity density (FCD) between 458 subjects with ASD and 517 TDCs from the ABIDE database. We quantified the inter- and intra-hemispheric FCDs in the brain by counting the number of functional connectivity with all voxels in the opposite and same hemispheric brain regions, respectively. Relative to TDCs, both inter- and intra-hemispheric FCDs in the posterior cingulate cortex, lingual/parahippocampal gyrus, and postcentral gyrus were significantly decreased in subjects with ASD. Moreover, in the ASD group, the restricted and repetitive behavior subscore of the Autism Diagnostic Observation Schedule (ADOS-RRB) score showed significant negative correlations with the average inter-hemispheric FCD and contralateral FCD in the lingual/parahippocampal gyrus cluster. Also, the ADOS-RRB score showed significant negative correlations with the average contralateral FCD in the default mode network regions such as the posterior cingulate cortex and precuneus. Taken together, our findings imply that a deficit of non-social functioning processing in ASD such as restricted and repetitive behaviors and sensory hypersensitivity could be determined via both inter- and intra-hemispheric functional disconnections. PMID:27199653

  13. Abnormalities of Inter- and Intra-Hemispheric Functional Connectivity in Autism Spectrum Disorders: A Study Using the Autism Brain Imaging Data Exchange Database

    PubMed Central

    Lee, Jung Min; Kyeong, Sunghyun; Kim, Eunjoo; Cheon, Keun-Ah

    2016-01-01

    Recently, the Autism Brain Imaging Data Exchange (ABIDE) project revealed decreased functional connectivity in individuals with Autism Spectrum Disorders (ASD) relative to the typically developing controls (TDCs). However, it is still questionable whether the source of functional under-connectivity in subjects with ASD is equally contributed by the ipsilateral and contralateral parts of the brain. In this study, we decomposed the inter- and intra-hemispheric regions and compared the functional connectivity density (FCD) between 458 subjects with ASD and 517 TDCs from the ABIDE database. We quantified the inter- and intra-hemispheric FCDs in the brain by counting the number of functional connectivity with all voxels in the opposite and same hemispheric brain regions, respectively. Relative to TDCs, both inter- and intra-hemispheric FCDs in the posterior cingulate cortex, lingual/parahippocampal gyrus, and postcentral gyrus were significantly decreased in subjects with ASD. Moreover, in the ASD group, the restricted and repetitive behavior subscore of the Autism Diagnostic Observation Schedule (ADOS-RRB) score showed significant negative correlations with the average inter-hemispheric FCD and contralateral FCD in the lingual/parahippocampal gyrus cluster. Also, the ADOS-RRB score showed significant negative correlations with the average contralateral FCD in the default mode network regions such as the posterior cingulate cortex and precuneus. Taken together, our findings imply that a deficit of non-social functioning processing in ASD such as restricted and repetitive behaviors and sensory hypersensitivity could be determined via both inter- and intra-hemispheric functional disconnections. PMID:27199653

  14. Subcortical contributions to effective connectivity in brain networks supporting imitation.

    PubMed

    Jack, Allison; Englander, Zoë A; Morris, James P

    2011-11-01

    Using functional magnetic resonance imaging (fMRI), we investigated effective connectivity in brain networks supporting imitation. Despite extensive reports of regional functional specialization underlying action perception, action execution and imitation, our understanding of the potential contribution of subcortical sites is limited, as is our knowledge of how regions displaying functional specialization interact with each other on a system level. While in the scanner, participants performed a simple imitation paradigm with three conditions: Observe trials, in which participants passively viewed a human actor executing a sequence of four finger presses on a keypad; Imitate trials, in which participants imitated the actor's finger presses on a keyboard; and Execute trials, in which participants also executed finger presses but did so based on visuospatial cues in the absence of the actor's hand. Relative to the Execute condition, Imitate trials evoked significantly more activity in superior and inferior parietal lobules (SPL, IPL), posterior superior temporal sulcus (pSTS), and in a ventral aspect of dorsal premotor cortex (PMd). Psychophysiological interaction (PPI) analysis, a means of assessing effective connectivity, revealed significant interactions with regions of cerebellar lobule VII from seeds both in the right pSTS and right SPL, such that activity in these sites was more highly correlated during imitation. A similar interaction was found between right pSTS and left IPL. These results clarify the role of cortical regions supporting action observation, action execution and imitation, and highlight the role the cerebellum may play in facilitating both motor and nonmotor aspects of imitation. PMID:21958651

  15. Effective Connectivity Reveals Strategy Differences in an Expert Calculator

    PubMed Central

    Minati, Ludovico; Sigala, Natasha

    2013-01-01

    Mathematical reasoning is a core component of cognition and the study of experts defines the upper limits of human cognitive abilities, which is why we are fascinated by peak performers, such as chess masters and mental calculators. Here, we investigated the neural bases of calendrical skills, i.e. the ability to rapidly identify the weekday of a particular date, in a gifted mental calculator who does not fall in the autistic spectrum, using functional MRI. Graph-based mapping of effective connectivity, but not univariate analysis, revealed distinct anatomical location of “cortical hubs” supporting the processing of well-practiced close dates and less-practiced remote dates: the former engaged predominantly occipital and medial temporal areas, whereas the latter were associated mainly with prefrontal, orbitofrontal and anterior cingulate connectivity. These results point to the effect of extensive practice on the development of expertise and long term working memory, and demonstrate the role of frontal networks in supporting performance on less practiced calculations, which incur additional processing demands. Through the example of calendrical skills, our results demonstrate that the ability to perform complex calculations is initially supported by extensive attentional and strategic resources, which, as expertise develops, are gradually replaced by access to long term working memory for familiar material. PMID:24086291

  16. Piezoelectric constant for binary piezoelectric 0-3 connectivity composites and the effect of mixed connectivity

    NASA Astrophysics Data System (ADS)

    Jayasundere, N.; Smith, B. V.; Dunn, J. R.

    1994-09-01

    An analytic expression is presented for the piezoelectric d constant of a binary piezoelectric 0-3 connectivity composite. The expression is developed under the limiting assumption that the dielectric constant of the ceramic is much greater than the matrix. Predictions made using the theory compare very favorably with available experimental data. A 0-3/1-3 mixed connectivity model is also described for composites in which the average piezoceramic particle size is a significant fraction of the thickness of the composite.

  17. The effect of connectives on the selection of arguments: implicit consequentiality bias for the connective "but".

    PubMed

    Rigalleau, François; Guerry, Michèle; Granjon, Lionel

    2014-08-01

    Recent studies about the implicit causality of inter-personal verbs showed a symmetric implicit consequentiality bias for psychological verbs. This symmetry is less clear for action verbs because the verbs assigning the implicit cause to the object argument (e.g. "Peter protected John because he was in danger.") tend to assign the implicit consequence to the same argument (e.g. "Peter protected John so he was not hurt."). We replicated this result by comparing continuations of inter-personal events followed by a causal connective "because" or a consequence connective "so". Moreover, we found similar results when the consequence connective was replaced by a contrastive connective "but". This result was confirmed in a second experiment where we measured the time required to imagine a consistent continuation for a fragment finishing with "but s/he ...". The results were consistent with a contrastive connective introducing a denial of a consequence of the previous event. The results were consistent with a model suggesting that thematic roles and connectives can predict preferred co-reference relations. PMID:23982891

  18. Effects of multiple chemical, physical, and biological stressors on the incidence and types of abnormalities observed in Bermuda's cane toads (Rhinella marina).

    PubMed

    Bacon, Jamie P; Fort, Chelsea E; Todhunter, Brian; Mathis, Michael; Fort, Douglas J

    2013-06-01

    The interactive effects of contaminants and ultraviolet light (UV)-exposure on the incidence and types of abnormalities observed were measured in newly metamorphosed cane toads (Rhinella marina) from four Bermuda ponds contaminated with petrochemicals and metals. Abnormalities were compared in toadlets that were field-collected, reared in predator exclusion cages, reared in laboratory microcosms exposed to control media or corresponding pond media, and reared in laboratory microcosms exposed to UV-light and control media or media from two ponds. Percent abnormal for field-collected, cage-reared, and microcosm-reared toadlets were equivalent per site and ranged between 14% and 63%. All treatments produced similar limb abnormalities but the percentage of hind versus forelimb defects was statistically greater only in field-collected toadlets. UV-exposed control media did not induce abnormalities in larvae exhibiting no maternal effect, and did not alter the types of abnormalities observed in larvae exhibiting a maternal or latent effect. Site media treatments without UV exposure induced significant cephalic and limb abnormalities, proved additive to the observed maternal/latent effect, and produced limb defects predominantly in forelimbs. Concurrent exposure to site media and UV-light induced similar types of abnormalities but a significantly higher percentage of hind limb abnormalities (68-89%) than exposure to site media alone (7-13%). Our results suggest that the types of abnormalities expressed were principally determined by direct and/or transgenerational contaminant exposure, but that UV-light exposure caused limb abnormalities to occur primarily in the hind limbs, mirroring field observations. Our field observations also suggest that ectromelia and brachydactyly in some field-collected specimens may be predator-induced. PMID:23526808

  19. Effective connectivity of visual word recognition and homophone orthographic errors

    PubMed Central

    Guàrdia-Olmos, Joan; Peró-Cebollero, Maribel; Zarabozo-Hurtado, Daniel; González-Garrido, Andrés A.; Gudayol-Ferré, Esteve

    2015-01-01

    The study of orthographic errors in a transparent language like Spanish is an important topic in relation to writing acquisition. The development of neuroimaging techniques, particularly functional magnetic resonance imaging (fMRI), has enabled the study of such relationships between brain areas. The main objective of the present study was to explore the patterns of effective connectivity by processing pseudohomophone orthographic errors among subjects with high and low spelling skills. Two groups of 12 Mexican subjects each, matched by age, were formed based on their results in a series of ad hoc spelling-related out-scanner tests: a high spelling skills (HSSs) group and a low spelling skills (LSSs) group. During the f MRI session, two experimental tasks were applied (spelling recognition task and visuoperceptual recognition task). Regions of Interest and their signal values were obtained for both tasks. Based on these values, structural equation models (SEMs) were obtained for each group of spelling competence (HSS and LSS) and task through maximum likelihood estimation, and the model with the best fit was chosen in each case. Likewise, dynamic causal models (DCMs) were estimated for all the conditions across tasks and groups. The HSS group’s SEM results suggest that, in the spelling recognition task, the right middle temporal gyrus, and, to a lesser extent, the left parahippocampal gyrus receive most of the significant effects, whereas the DCM results in the visuoperceptual recognition task show less complex effects, but still congruent with the previous results, with an important role in several areas. In general, these results are consistent with the major findings in partial studies about linguistic activities but they are the first analyses of statistical effective brain connectivity in transparent languages. PMID:26042070

  20. Abnormal dephosphorylation effect on NMDA receptor regulation in ALS spinal cord.

    PubMed

    Wagey, R; Krieger, C; Shaw, C A

    1997-01-01

    Previous studies have demonstrated a significant reduction of N-methyl-D-aspartate (NMDA) receptor binding in spinal cord sections from patients who died with amyotrophic lateral sclerosis (ALS) compared to that in control patients. The reduction in NMDA receptor binding in ALS could be increased toward control values by treatment with phorbol ester, suggesting a role for receptor protein phosphorylation in this disorder. In the present study we have evaluated the time course of recovery of [3H]MK-801 binding following phorbol ester treatment to assess protein phosphatase activity in spinal cord sections from ALS and control subjects. Phorbol ester-stimulated changes in [3H]MK-801 binding returned to untreated values significantly faster in ALS tissue compared to control and could not be blocked by the coapplication of the protein phosphatase inhibitors sodium vanadate or sodium beta-D-glycerol phosphate. Okadaic acid coapplication blocked recovery in both ALS and control tissue at a concentration range at which phosphatase 2B (calcineurin) would likely be inhibited. The results suggest that abnormal levels or activity of protein phosphatases, including calcineurin, may be involved in the abnormal levels of NMDA receptors in ALS and may play some role in the pathogenesis of the disease. PMID:9440123

  1. Effect of Process Parameters on Abnormal Grain Growth during Friction Stir Processing of a Cast Al Alloy

    SciTech Connect

    Jana, Saumyadeep; Mishra, Rajiv S.; Baumann, John A.; Grant, Glenn J.

    2010-11-25

    The effects of process parameters and friction stir processing (FSP) run configurations on the stability of nugget microstructure at elevated temperatures were evaluated. Cast plates of an Al-7Si- 0.6Mg alloy were friction stir processed using a combination of tool rotation rates and tool traverse speeds. All single pass runs showed some extent of abnormal grain growth (AGG), whereas multi-pass runs were more resistant to AGG. Additionally, higher tool rpm was found to be beneficial for controlling AGG. These effects were analyzed by comparing the result of this work with other published results and AGG models.

  2. Effect of cocaine dependence on brain connections: clinical implications.

    PubMed

    Ma, Liangsuo; Steinberg, Joel L; Moeller, F Gerard; Johns, Sade E; Narayana, Ponnada A

    2015-01-01

    Cocaine dependence (CD) is associated with several cognitive deficits. Accumulating evidence, based on human and animal studies, has led to models for interpreting the neural basis of cognitive functions as interactions between functionally related brain regions. In this review, we focus on magnetic resonance imaging (MRI) studies using brain connectivity techniques as related to CD. The majority of these brain connectivity studies indicated that cocaine use is associated with altered brain connectivity between different structures, including cortical-striatal regions and default mode network. In cocaine users some of the altered brain connectivity measures are associated with behavioral performance, history of drug use, and treatment outcome. The implications of these brain connectivity findings to the treatment of CD and the pros and cons of the major brain connectivity techniques are discussed. Finally potential future directions in cocaine use disorder research using brain connectivity techniques are briefly described. PMID:26512421

  3. Diabetes-induced myelin abnormalities are associated with an altered lipid pattern: protective effects of LXR activation[S

    PubMed Central

    Cermenati, Gaia; Abbiati, Federico; Cermenati, Solei; Brioschi, Elisabetta; Volonterio, Alessandro; Cavaletti, Guido; Saez, Enrique; De Fabiani, Emma; Crestani, Maurizio; Garcia-Segura, Luis M.; Melcangi, Roberto C.; Caruso, Donatella; Mitro, Nico

    2012-01-01

    Diabetic peripheral neuropathy (DPN) is characterized by myelin abnormalities; however, the molecular mechanisms underlying such deficits remain obscure. To uncover the effects of diabetes on myelin alterations, we have analyzed myelin composition. In a streptozotocin-treated rat model of diabetic neuropathy, analysis of sciatic nerve myelin lipids revealed that diabetes alters myelin's phospholipid, FA, and cholesterol content in a pattern that can modify membrane fluidity. Reduced expression of relevant genes in the FA biosynthetic pathway and decreased levels of the transcriptionally active form of the lipogenic factor sterol-regulatory element binding factor-1c (SREBF-1c) were found in diabetic sciatic nerve. Expression of myelin's major protein, myelin protein zero (P0), was also suppressed by diabetes. In addition, we confirmed that diabetes induces sciatic nerve myelin abnormalities, primarily infoldings that have previously been associated with altered membrane fluidity. In a diabetic setting, synthetic activator of the nuclear receptor liver X receptor (LXR) increased SREBF-1c function and restored myelin lipid species and P0 expression levels to normal. These LXR-modulated improvements were associated with restored myelin structure in sciatic nerve and enhanced performance in functional tests such as thermal nociceptive threshold and nerve conduction velocity. These findings demonstrate an important role for the LXR-SREBF-1c axis in protection from diabetes-induced myelin abnormalities. PMID:22158827

  4. Serial study of the effect of radiotherapy on semen parameters, hamster egg penetration rates, and lymphocyte chromosome abnormalities

    SciTech Connect

    Martin, R.H.; Barnes, M.; Arthur, K.; Ringrose, T.; Douglas, G.

    1984-02-01

    This study was designed to assess the long-term effects of radiotherapy (RT) on male fertility and the induction of lymphocyte and sperm chromosome abnormalities. This preliminary report provides information on 11 cancer patients (mainly seminomas) treated by RT (testicular dose, 44 to 499 rads). All 11 men were studied pre-RT and at intervals post-RT. The pre-RT semen profile varied considerably, but, in general, the profile was poor with a mean sperm concentration of 19.4 x 10/sup 6/ ml and a mean hamster egg penetration rate of 5%. One month after RT, the sperm concentration decreased and hamster egg penetration was 0% in all men. At 3 and 12 months post-RT, all but two patients were azoospermic. By 24 months post-RT, 9 of 11 patients had regained sperm production and 5 had sperm capable of hamster egg penetration. The three men who have been studied 36 months post-RT had a mean sperm concentration of 45.3 x 10/sup 6/ ml, and all had positive hamster egg penetration tests, although two of the three men had very low penetration rates (2% and 4%). Lymphocyte chromosome analysis demonstrated a striking frequency of chromosome abnormalities post-RT which decreased with time (pre-RT, 0%; 1 month, 42.4%; 3 months, 24.7%; 12 months, 13.8%; 24 months, 11.2%; and 36 months, 10.0%). Thus, it appears that sperm production starts to recover 2 to 3 years after RT when the frequency of lymphocyte chromosome abnormalities has decreased, but the sperm may not be fully functional at this time, as evidenced by poor rates of hamster egg penetration. Future studies of sperm chromosome analysis in these men will determine whether this impairment of the sperm is associated with meiotic chromosome abnormalities.

  5. Different forms of effective connectivity in primate frontotemporal pathways

    PubMed Central

    Petkov, Christopher I.; Kikuchi, Yukiko; Milne, Alice E.; Mishkin, Mortimer; Rauschecker, Josef P.; Logothetis, Nikos K.

    2015-01-01

    It is generally held that non-primary sensory regions of the brain have a strong impact on frontal cortex. However, the effective connectivity of pathways to frontal cortex is poorly understood. Here we microstimulate sites in the superior temporal and ventral frontal cortex of monkeys and use functional magnetic resonance imaging to evaluate the functional activity resulting from the stimulation of interconnected regions. Surprisingly, we find that, although certain earlier stages of auditory cortical processing can strongly activate frontal cortex, downstream auditory regions, such as voice-sensitive cortex, appear to functionally engage primarily an ipsilateral temporal lobe network. Stimulating other sites within this activated temporal lobe network shows strong activation of frontal cortex. The results indicate that the relative stage of sensory processing does not predict the level of functional access to the frontal lobes. Rather, certain brain regions engage local networks, only parts of which have a strong functional impact on frontal cortex. PMID:25613079

  6. Different forms of effective connectivity in primate frontotemporal pathways.

    PubMed

    Petkov, Christopher I; Kikuchi, Yukiko; Milne, Alice E; Mishkin, Mortimer; Rauschecker, Josef P; Logothetis, Nikos K

    2015-01-01

    It is generally held that non-primary sensory regions of the brain have a strong impact on frontal cortex. However, the effective connectivity of pathways to frontal cortex is poorly understood. Here we microstimulate sites in the superior temporal and ventral frontal cortex of monkeys and use functional magnetic resonance imaging to evaluate the functional activity resulting from the stimulation of interconnected regions. Surprisingly, we find that, although certain earlier stages of auditory cortical processing can strongly activate frontal cortex, downstream auditory regions, such as voice-sensitive cortex, appear to functionally engage primarily an ipsilateral temporal lobe network. Stimulating other sites within this activated temporal lobe network shows strong activation of frontal cortex. The results indicate that the relative stage of sensory processing does not predict the level of functional access to the frontal lobes. Rather, certain brain regions engage local networks, only parts of which have a strong functional impact on frontal cortex. PMID:25613079

  7. Quantitative Study on the Effect of Abnormalities on Respiration-Induced Kidney Movement.

    PubMed

    Abhilash, Rakkunedeth H; Chauhan, Sunita; Che, Ma Voon; Ooi, Chin-Chin; Bakar, Rafidah Abu; Lo, Richard H G

    2016-07-01

    Respiration-induced movement of abdominal organs hampers the targeting accuracy of non-invasive surgical techniques such as focused ultrasound surgery and radiosurgery. Unaccounted organ movement can result in either under dosage or damage to intervening healthy tissues. The respiration-induced movement is known to be significantly large in kidneys; however, the impact of abnormalities such as tumors and cysts on kidney movement is poorly understood. In this study, we quantified the movement patterns of kidneys in 48 normal and 62 affected kidneys (43 calcified cysts, 11 angiomyolipomas, 4 renal cell carcinomas and 4 polycystic kidneys) using ultrasound and simultaneously tracked the respiratory movement patterns using a stereo camera system. The kidneys were localized from 2-D ultrasound sequences using a template matching technique. The average movements of the right and left kidneys were, respectively, 24.54 ± 6.4 and 17.06 ± 3.66 mm in the superior-inferior and 13.62 ± 3.71 and 9.80 ± 3.32 mm in the transverse directions. Average movement in the superior-inferior direction of normal kidneys was greater than that of affected kidneys for both right (26.9 ± 5.1 vs. 22.6 ± 3.3, p < 0.001) and left (17.8 ± 2.5 vs. 16.1 ± 4.2, p = 0.01) kidneys. On the basis of spatial extent of abnormality, affected kidneys were categorized as category A (<10 mm in 26 patients), category B (10-20 mm in 22 patients) and category C (>20 mm in 14 patients). Compared with normal patients, the extent of movement was significantly reduced in abnormal categories B (p < 0.001) and C (p < 0.001), but the change was not significant in category A (p = 0.04). Hysteresis plots of the kidneys revealed a maximum change of 12.3 mm. The movement patterns of the kidneys also closely correlated with the respiratory movement pattern (Pearson correlation = 0.89 [right] and 0.87 [left]). We expect that the movement pattern analyses and quantification carried out

  8. Control of Abnormal Synchronization in Neurological Disorders

    PubMed Central

    Popovych, Oleksandr V.; Tass, Peter A.

    2014-01-01

    In the nervous system, synchronization processes play an important role, e.g., in the context of information processing and motor control. However, pathological, excessive synchronization may strongly impair brain function and is a hallmark of several neurological disorders. This focused review addresses the question of how an abnormal neuronal synchronization can specifically be counteracted by invasive and non-invasive brain stimulation as, for instance, by deep brain stimulation for the treatment of Parkinson’s disease, or by acoustic stimulation for the treatment of tinnitus. On the example of coordinated reset (CR) neuromodulation, we illustrate how insights into the dynamics of complex systems contribute to successful model-based approaches, which use methods from synergetics, non-linear dynamics, and statistical physics, for the development of novel therapies for normalization of brain function and synaptic connectivity. Based on the intrinsic multistability of the neuronal populations induced by spike timing-dependent plasticity (STDP), CR neuromodulation utilizes the mutual interdependence between synaptic connectivity and dynamics of the neuronal networks in order to restore more physiological patterns of connectivity via desynchronization of neuronal activity. The very goal is to shift the neuronal population by stimulation from an abnormally coupled and synchronized state to a desynchronized regime with normalized synaptic connectivity, which significantly outlasts the stimulation cessation, so that long-lasting therapeutic effects can be achieved. PMID:25566174

  9. Effects of Wildfire Disturbances on Multi-scale Connectivity

    NASA Astrophysics Data System (ADS)

    Malkinson, Dan; Wittenberg, Lea

    2013-04-01

    Eco-geomorphic systems are characterized by interactions between system components which operate at various spatial and temporal scales. Many processes in these systems are scale-dependent (point-plot-slope-basin), and vary over different spatial extents. Within any landscape unit the magnitude and nature of interactions between system elements and processes vary, suggesting that variables and processes that are interdependent at one scale may be independent at another. Disturbances can have profound effects on scale-dependent processes, 'reframing' spatial boundaries between the various functional-geomorphic units. Wildfires, for example, result in the removal of woody patches, which might be translated to displacement of patch boundaries, essentially homogenizing land cover and facilitating hydrological connectivity between the burnt patches and consequently among the nested scales (patch-slope-basin). Further, processes such as fire-induced hydrophobicity which have important hydrological implications at the point scale, do not necessarily translate to significant increase in runoff at larger scales. Accordingly, structural and mechanical changes caused by wildfires, might alter both the boundaries as well as the role of scale-dependent processes, resulting in increased connectivity between the spatial units and consequently an overall intensification of post-fire hydrological response of the system. Accordingly we try to statistically identify what are the threshold values at which processes operating at one scale are replaced by processes operating at other scales, in contrast to the arbitrarily defined scales. To identify such thresholds we compiled data from over 60 published studies which addressed sediment yield following fire events at various spatial scales (2 m2 plots - 1660 ha basin). The data were ranked from the smallest scale to the largest, and we incrementally calculated the coefficient determination (R^2) of the data by successively adding each

  10. The effects of anatomical information and observer expertise on abnormality detection task

    NASA Astrophysics Data System (ADS)

    Zhang, L.; Cavaro-Ménard, C.; Le Callet, P.; Cooper, L. H. K.; Hunault, G.; Tanguy, J.-Y.

    2011-03-01

    This paper presents a novel study investigating the influences of Magnetic Resonance (MR) image anatomical information and observer expertise on an abnormality detection task. MRI is exquisitely sensitive for detecting brain abnormalities, particularly in the evaluation of white matter diseases, e.g. multiple sclerosis (MS). For this reason, MS lesions are simulated as the target stimuli for detection in the present study. Two different image backgrounds are used in the following experiments: a) homogeneous region of white matter tissue, and b) one slice of a healthy brain MR image. One expert radiologist (more than 10 years' experience), three radiologists (less than 5 years' experience) and eight naïve observers (without any prior medical knowledge) have performed these experiments, during which they have been asked different questions dependent upon level of experience; the three radiologists and eight naïve observers were asked if they were aware of any hyper-signal, likely to represent an MS lesion, while the most experienced consultant was asked if a clinically significant sign was present. With the percentages of response "yes" displayed on the y-axis and the lesion intensity contrasts on the x-axis, psychometric function is generated from the observer' responses. Results of psychometric functions and calculated thresholds indicate that radiologists have better hyper-signal detection ability than naïve observers, which is intuitively shown by the lower simple visibility thresholds of radiologists. However, when radiologists perform a task with clinical implications, e.g. to detect a clinically significant sign, their detection thresholds are elevated. Moreover, the study indicates that for the radiologists, the simple visibility thresholds remain the same with and without the anatomical information, which reduces the threshold for the clinically significant sign detection task. Findings provide further insight into human visual system processing for this

  11. Effective Programming for Youth: The Education/Work Connection.

    ERIC Educational Resources Information Center

    Wisconsin Univ., Madison. Wisconsin Vocational Studies Center.

    Designed to serve as a resource to persons who work with youth and who plan activities to improve the education/work connection, this report identifies existing programs and activities that address the education-to-work connection and work to improve youth employment. It consists of three sections. The first section contains an overview of youth…

  12. Effects of Check and Connect on Attendance, Behavior, and Academics: A Randomized Effectiveness Trial

    ERIC Educational Resources Information Center

    Maynard, Brandy R.; Kjellstrand, Elizabeth K.; Thompson, Aaron M.

    2014-01-01

    Objectives: This study examined the effects of Check & Connect (C&C) on the attendance, behavior, and academic outcomes of at-risk youth in a field-based effectiveness trial. Method: A multisite randomized block design was used, wherein 260 primarily Hispanic (89%) and economically disadvantaged (74%) students were randomized to treatment…

  13. Effect of ferrite formation on abnormal austenite grain coarsening in low-alloy steels during the hot rolling process

    NASA Astrophysics Data System (ADS)

    Asahi, Hitoshi; Yagi, Akira; Ueno, Masakatsu

    1998-05-01

    Abnormal coarsening of austenite (γ) grains occurred in low-alloy steels during a seamless pipe hotrolling process. Often, the grains became several hundred micrometers in diameter. This made it difficult to apply direct quenching to produce high-performance pipes. The phenomenon of grain coarsening was successfully reproduced using a thermomechanical simulator, and the factors which affected grain coarsening were clarified. The mechanism was found to be basically strain-induced grain rowth which occurred during reheating at around 930 °C. Furthermore, once a pipe temperature decreased to the dual-phase region after the minimal hot working and prior to the reheating process, the grain coarsening was more pronounced. It was understood that the formation of ferrite along grain boundaries had the role of reducing the migration of grain boundaries into neighboring grains, leaving a strain-free, recrystallized region behind. This abnormal grain coarsening was found to be effectively prevented by an addition of Nb, the content of which varied depending on the C content. The effect of the Nb addition was confirmed by an in-line test.

  14. Effect of ferrite formation on abnormal austenite grain coarsening in low-alloy steels during hot rolling process

    SciTech Connect

    Asahi, Hitoshi; Ueno, Masakatsu; Yagi, Akira

    1998-05-01

    Abnormal coarsening of austenite ({gamma}) grains occurred in low-alloy steels during a seamless pipe hot-rolling process. Often, the grains became several hundred micrometer in diameter. This made it difficult to apply direct quenching to produce high-performance pipes. The phenomenon of grain coarsening was successfully reproduced using a thermomechanical simulator, and the factors which affected grain coarsening were clarified. The mechanism was found to be basically strain-induced grain growth which occurred during reheating at around 930 C. Furthermore, once a pipe temperature decreased to the dual-phase region after the minimal hot working and prior to the reheating process, the grain coarsening was more pronounced. It was understood that the formation of ferrite along grain boundaries had the role of reducing the migration of grain boundaries into neighboring grains, leaving a strain-free, recrystallized region behind. This abnormal grain coarsening was found to be effectively prevented by an addition of Nb, the content of which varied depending on the C content. The effect of the Nb addition was confirmed by an in-line test.

  15. The Effect of Sorafenib, Tadalafil and Macitentan Treatments on Thyroxin-Induced Hemodynamic Changes and Cardiac Abnormalities

    PubMed Central

    Saad, Nancy S.; Floyd, Kyle; Ahmed, Amany A. E.; Mohler, Peter J.

    2016-01-01

    Multikinase inhibitors (e.g. Sorafenib), phosphodiesterase-5 inhibitors (e.g. Tadalafil), and endothelin-1 receptor blockers (e.g. Macitentan) exert influential protection in a variety of animal models of cardiomyopathy; however, their effects on thyroxin-induced cardiomyopathy have never been investigated. The goal of the present study was to assess the functional impact of these drugs on thyroxin-induced hemodynamic changes, cardiac hypertrophy and associated altered responses of the contractile myocardium both in-vivo at the whole heart level and ex-vivo at the cardiac tissue level. Control and thyroxin (500 μg/kg/day)-treated mice with or without 2-week treatments of sorafenib (10 mg/kg/day; I.P), tadalafil (1 mg/kg/day; I.P or 4 mg/kg/day; oral), macitentan (30 and 100 mg/kg/day; oral), and their vehicles were studied. Blood pressure, echocardiography and electrocardiogram were non-invasively evaluated, followed by ex-vivo assessments of isolated multicellular cardiac preparations. Thyroxin increased blood pressure, resulted in cardiac hypertrophy and left ventricular dysfunction in-vivo. Also, it caused contractile abnormalities in right ventricular papillary muscles ex-vivo. None of the drug treatments were able to significantly attenuate theses hemodynamic changes or cardiac abnormalities in thyroxin-treated mice. We show here for the first time that multikinase (raf1/b, VEGFR, PDGFR), phosphodiesterase-5, and endothelin-1 pathways have no major role in thyroxin-induced hemodynamic changes and cardiac abnormalities. In particular, our data show that the involvement of endothelin-1 pathway in thyroxine-induced cardiac hypertrophy/dysfunction seems to be model-dependent and should be carefully interpreted. PMID:27082116

  16. The Effect of Sorafenib, Tadalafil and Macitentan Treatments on Thyroxin-Induced Hemodynamic Changes and Cardiac Abnormalities.

    PubMed

    Saad, Nancy S; Floyd, Kyle; Ahmed, Amany A E; Mohler, Peter J; Janssen, Paul M L; Elnakish, Mohammad T

    2016-01-01

    Multikinase inhibitors (e.g. Sorafenib), phosphodiesterase-5 inhibitors (e.g. Tadalafil), and endothelin-1 receptor blockers (e.g. Macitentan) exert influential protection in a variety of animal models of cardiomyopathy; however, their effects on thyroxin-induced cardiomyopathy have never been investigated. The goal of the present study was to assess the functional impact of these drugs on thyroxin-induced hemodynamic changes, cardiac hypertrophy and associated altered responses of the contractile myocardium both in-vivo at the whole heart level and ex-vivo at the cardiac tissue level. Control and thyroxin (500 μg/kg/day)-treated mice with or without 2-week treatments of sorafenib (10 mg/kg/day; I.P), tadalafil (1 mg/kg/day; I.P or 4 mg/kg/day; oral), macitentan (30 and 100 mg/kg/day; oral), and their vehicles were studied. Blood pressure, echocardiography and electrocardiogram were non-invasively evaluated, followed by ex-vivo assessments of isolated multicellular cardiac preparations. Thyroxin increased blood pressure, resulted in cardiac hypertrophy and left ventricular dysfunction in-vivo. Also, it caused contractile abnormalities in right ventricular papillary muscles ex-vivo. None of the drug treatments were able to significantly attenuate theses hemodynamic changes or cardiac abnormalities in thyroxin-treated mice. We show here for the first time that multikinase (raf1/b, VEGFR, PDGFR), phosphodiesterase-5, and endothelin-1 pathways have no major role in thyroxin-induced hemodynamic changes and cardiac abnormalities. In particular, our data show that the involvement of endothelin-1 pathway in thyroxine-induced cardiac hypertrophy/dysfunction seems to be model-dependent and should be carefully interpreted. PMID:27082116

  17. Dental and maxillofacial abnormalities in long-term survivors of childhood cancer: effects of treatment with chemotherapy and radiation to the head and neck

    SciTech Connect

    Jaffe, N.; Toth, B.B.; Hoar, R.E.; Ried, H.L.; Sullivan, M.P.; McNeese, M.D.

    1984-06-01

    Sixty-eight long-term survivors of childhood cancer were evaluated for dental and maxillofacial abnormalities. Forty-five patients had received maxillofacial radiation for lymphoma, leukemia, rhabdomyosarcoma, and miscellaneous tumors. Forty-three of the 45 patients and the remaining 23 who had not received maxillofacial radiation also received chemotherapy. Dental and maxillofacial abnormalities were detected in 37 of the 45 (82%) radiated patients. Dental abnormalities comprised foreshortening and blunting of roots, incomplete calcification, premature closure of apices, delayed or arrested tooth development, and caries. Maxillofacial abnormalities comprised trismus, abnormal occlusal relationships, and facial deformities. The abnormalities were more severe in those patients who received radiation at an earlier age and at higher dosages. Possible chemotherapeutic effects in five of 23 patients who received treatment for tumors located outside the head and neck region comprised acquired amelogenesis imperfecta, microdontia of bicuspid teeth, and a tendency toward thinning of roots with an enlarged pulp chamber. Dental and maxillofacial abnormalities should be recognized as a major consequence of maxillofacial radiation in long-term survivors of childhood cancer, and attempts to minimize or eliminate such sequelae should involve an effective interaction between radiation therapists, and medical and dental oncologists.

  18. Dental and maxillofacial abnormalities in long-term survivors of childhood cancer: effects of treatment with chemotherapy and radiation to the head and neck.

    PubMed

    Jaffe, N; Toth, B B; Hoar, R E; Ried, H L; Sullivan, M P; McNeese, M D

    1984-06-01

    Sixty-eight long-term survivors of childhood cancer were evaluated for dental and maxillofacial abnormalities. Forty-five patients had received maxillofacial radiation for lymphoma, leukemia, rhabdomyosarcoma, and miscellaneous tumors. Forty-three of the 45 patients and the remaining 23 who had not received maxillofacial radiation also received chemotherapy. Dental and maxillofacial abnormalities were detected in 37 of the 45 (82%) radiated patients. Dental abnormalities comprised foreshortening and blunting of roots, incomplete calcification, premature closure of apices, delayed or arrested tooth development, and caries. Maxillofacial abnormalities comprised trismus, abnormal occlusal relationships, and facial deformities. The abnormalities were more severe in those patients who received radiation at an earlier age and at higher dosages. Possible chemotherapeutic effects in five of 23 patients who received treatment for tumors located outside the head and neck region comprised acquired amelogenesis imperfecta, microdontia of bicuspid teeth, and a tendency toward thinning of roots with an enlarged pulp chamber. Dental and maxillofacial abnormalities should be recognized as a major consequence of maxillofacial radiation in long-term survivors of childhood cancer, and attempts to minimize or eliminate such sequelae should involve an effective interaction between radiation therapists, and medical and dental oncologists. PMID:6728583

  19. Replacement of chlorpromazine with other neuroleptics: effect on abnormal skin pigmentation and ocular changes.

    PubMed Central

    Lal, S; Bloom, D; Silver, B; Desjardins, B; Krishnan, B; Thavundayil, J; Thompson, T

    1993-01-01

    This paper describes the outcome of 15 patients with chlorpromazine (CPZ)-induced abnormal skin pigmentation (ASP) in whom CPZ was replaced with other neuroleptics for three to 13 years. Complete resolution of ASP occurred over a period of six months to five years following substitution with haloperidol (four patients), levomepromazine (three patients), trifluoperazine (one patient), thioproperazine (one patient) as the sole neuroleptic, by a combination of two of the three phenothiazines (four patients) or haloperidol plus pipotiazine (one patient). Resolution was maintained during the remainder of the follow-up period. In one patient, at final follow-up, marked improvement was present three years after CPZ was replaced with levomepromazine. Bilateral lenticular pigmentary deposits persisted in all eight patients examined 3.3 to 13 years after replacing CPZ and less than three months to nine years after resolution of ASP; improvement was noted in only one of these patients. Bilateral endothelial corneal deposits, present in five patients while on CPZ therapy, had disappeared in two patients seven and 13 years, respectively, after replacing CPZ; improvement was noted in two other patients. These findings indicate that: 1. CPZ-induced ASP is completely reversible in most, if not all, patients if CPZ is withdrawn; 2. a variety of neuroleptics including other phenothiazines can be used to replace CPZ without risk of re-emergence of ASP; 3. CPZ-induced lenticular changes persist whereas corneal changes may resolve slowly over a period of many years following replacement of CPZ; 4. ASP and ocular changes induced by CPZ may be subserved by two different pathophysiological mechanisms. PMID:8104031

  20. Rich-Club Organization in Effective Connectivity among Cortical Neurons.

    PubMed

    Nigam, Sunny; Shimono, Masanori; Ito, Shinya; Yeh, Fang-Chin; Timme, Nicholas; Myroshnychenko, Maxym; Lapish, Christopher C; Tosi, Zachary; Hottowy, Pawel; Smith, Wesley C; Masmanidis, Sotiris C; Litke, Alan M; Sporns, Olaf; Beggs, John M

    2016-01-20

    The performance of complex networks, like the brain, depends on how effectively their elements communicate. Despite the importance of communication, it is virtually unknown how information is transferred in local cortical networks, consisting of hundreds of closely spaced neurons. To address this, it is important to record simultaneously from hundreds of neurons at a spacing that matches typical axonal connection distances, and at a temporal resolution that matches synaptic delays. We used a 512-electrode array (60 μm spacing) to record spontaneous activity at 20 kHz from up to 500 neurons simultaneously in slice cultures of mouse somatosensory cortex for 1 h at a time. We applied a previously validated version of transfer entropy to quantify information transfer. Similar to in vivo reports, we found an approximately lognormal distribution of firing rates. Pairwise information transfer strengths also were nearly lognormally distributed, similar to reports of synaptic strengths. Some neurons transferred and received much more information than others, which is consistent with previous predictions. Neurons with the highest outgoing and incoming information transfer were more strongly connected to each other than chance, thus forming a "rich club." We found similar results in networks recorded in vivo from rodent cortex, suggesting the generality of these findings. A rich-club structure has been found previously in large-scale human brain networks and is thought to facilitate communication between cortical regions. The discovery of a small, but information-rich, subset of neurons within cortical regions suggests that this population will play a vital role in communication, learning, and memory. Significance statement: Many studies have focused on communication networks between cortical brain regions. In contrast, very few studies have examined communication networks within a cortical region. This is the first study to combine such a large number of neurons (several

  1. Rich-Club Organization in Effective Connectivity among Cortical Neurons

    PubMed Central

    Shimono, Masanori; Ito, Shinya; Yeh, Fang-Chin; Timme, Nicholas; Myroshnychenko, Maxym; Lapish, Christopher C.; Tosi, Zachary; Hottowy, Pawel; Smith, Wesley C.; Masmanidis, Sotiris C.; Litke, Alan M.; Sporns, Olaf; Beggs, John M.

    2016-01-01

    The performance of complex networks, like the brain, depends on how effectively their elements communicate. Despite the importance of communication, it is virtually unknown how information is transferred in local cortical networks, consisting of hundreds of closely spaced neurons. To address this, it is important to record simultaneously from hundreds of neurons at a spacing that matches typical axonal connection distances, and at a temporal resolution that matches synaptic delays. We used a 512-electrode array (60 μm spacing) to record spontaneous activity at 20 kHz from up to 500 neurons simultaneously in slice cultures of mouse somatosensory cortex for 1 h at a time. We applied a previously validated version of transfer entropy to quantify information transfer. Similar to in vivo reports, we found an approximately lognormal distribution of firing rates. Pairwise information transfer strengths also were nearly lognormally distributed, similar to reports of synaptic strengths. Some neurons transferred and received much more information than others, which is consistent with previous predictions. Neurons with the highest outgoing and incoming information transfer were more strongly connected to each other than chance, thus forming a “rich club.” We found similar results in networks recorded in vivo from rodent cortex, suggesting the generality of these findings. A rich-club structure has been found previously in large-scale human brain networks and is thought to facilitate communication between cortical regions. The discovery of a small, but information-rich, subset of neurons within cortical regions suggests that this population will play a vital role in communication, learning, and memory. SIGNIFICANCE STATEMENT Many studies have focused on communication networks between cortical brain regions. In contrast, very few studies have examined communication networks within a cortical region. This is the first study to combine such a large number of neurons (several

  2. Effects of normal and abnormal loading conditions on morphogenesis of the prenatal hip joint: application to hip dysplasia.

    PubMed

    Giorgi, Mario; Carriero, Alessandra; Shefelbine, Sandra J; Nowlan, Niamh C

    2015-09-18

    Joint morphogenesis is an important phase of prenatal joint development during which the opposing cartilaginous rudiments acquire their reciprocal and interlocking shapes. At an early stage of development, the prenatal hip joint is formed of a deep acetabular cavity that almost totally encloses the head. By the time of birth, the acetabulum has become shallower and the femoral head has lost substantial sphericity, reducing joint coverage and stability. In this study, we use a dynamic mechanobiological simulation to explore the effects of normal (symmetric), reduced and abnormal (asymmetric) prenatal movements on hip joint shape, to understand their importance for postnatal skeletal malformations such as developmental dysplasia of the hip (DDH). We successfully predict the physiological trends of decreasing sphericity and acetabular coverage of the femoral head during fetal development. We show that a full range of symmetric movements helps to maintain some of the acetabular depth and femoral head sphericity, while reduced or absent movements can lead to decreased sphericity and acetabular coverage of the femoral head. When an abnormal movement pattern was applied, a deformed joint shape was predicted, with an opened asymmetric acetabulum and the onset of a malformed femoral head. This study provides evidence for the importance of fetal movements in the prevention and manifestation of congenital musculoskeletal disorders such as DDH. PMID:26163754

  3. Effects of normal and abnormal loading conditions on morphogenesis of the prenatal hip joint: application to hip dysplasia

    PubMed Central

    Giorgi, Mario; Carriero, Alessandra; Shefelbine, Sandra J.; Nowlan, Niamh C.

    2015-01-01

    Joint morphogenesis is an important phase of prenatal joint development during which the opposing cartilaginous rudiments acquire their reciprocal and interlocking shapes. At an early stage of development, the prenatal hip joint is formed of a deep acetabular cavity that almost totally encloses the head. By the time of birth, the acetabulum has become shallower and the femoral head has lost substantial sphericity, reducing joint coverage and stability. In this study, we use a dynamic mechanobiological simulation to explore the effects of normal (symmetric), reduced and abnormal (asymmetric) prenatal movements on hip joint shape, to understand their importance for postnatal skeletal malformations such as developmental dysplasia of the hip (DDH). We successfully predict the physiological trends of decreasing sphericity and acetabular coverage of the femoral head during fetal development. We show that a full range of symmetric movements helps to maintain some of the acetabular depth and femoral head sphericity, while reduced or absent movements can lead to decreased sphericity and acetabular coverage of the femoral head. When an abnormal movement pattern was applied, a deformed joint shape was predicted, with an opened asymmetric acetabulum and the onset of a malformed femoral head. This study provides evidence for the importance of fetal movements in the prevention and manifestation of congenital musculoskeletal disorders such as DDH. PMID:26163754

  4. Effective Connectivity from Early Visual Cortex to Posterior Occipitotemporal Face Areas Supports Face Selectivity and Predicts Developmental Prosopagnosia

    PubMed Central

    Garrido, Lucia; Driver, Jon; Dolan, Raymond J.; Duchaine, Bradley C.; Furl, Nicholas

    2016-01-01

    Face processing is mediated by interactions between functional areas in the occipital and temporal lobe, and the fusiform face area (FFA) and anterior temporal lobe play key roles in the recognition of facial identity. Individuals with developmental prosopagnosia (DP), a lifelong face recognition impairment, have been shown to have structural and functional neuronal alterations in these areas. The present study investigated how face selectivity is generated in participants with normal face processing, and how functional abnormalities associated with DP, arise as a function of network connectivity. Using functional magnetic resonance imaging and dynamic causal modeling, we examined effective connectivity in normal participants by assessing network models that include early visual cortex (EVC) and face-selective areas and then investigated the integrity of this connectivity in participants with DP. Results showed that a feedforward architecture from EVC to the occipital face area, EVC to FFA, and EVC to posterior superior temporal sulcus (pSTS) best explained how face selectivity arises in both controls and participants with DP. In this architecture, the DP group showed reduced connection strengths on feedforward connections carrying face information from EVC to FFA and EVC to pSTS. These altered network dynamics in DP contribute to the diminished face selectivity in the posterior occipitotemporal areas affected in DP. These findings suggest a novel view on the relevance of feedforward projection from EVC to posterior occipitotemporal face areas in generating cortical face selectivity and differences in face recognition ability. SIGNIFICANCE STATEMENT Areas of the human brain showing enhanced activation to faces compared to other objects or places have been extensively studied. However, the factors leading to this face selectively have remained mostly unknown. We show that effective connectivity from early visual cortex to posterior occipitotemporal face areas gives

  5. Effects of Check & Connect on Attendance, Behavior, and Academics: A Randomized Effectiveness Trial

    ERIC Educational Resources Information Center

    Maynard, Brandy R.; Kjellstrand, Elizabeth K.; Thompson, Aaron M.

    2014-01-01

    The present study evaluates the effectiveness of Check & Connect (C&C) in a randomly assigned sample of students who were all receiving Communities in Schools (CIS) services. The research questions for the study include: Are there differences in attendance, academics, and behavior for CIS students who also receive C&C compared to…

  6. Parallel three-dimensional Monte Carlo simulations for effects of precipitates and sub-boundaries on abnormal grain growth of Goss grains in Fe-3%Si steel

    NASA Astrophysics Data System (ADS)

    Park, Chang-Soo; Na, Tae-Wook; Kang, Jul-Ki; Lee, Byeong-Joo; Han, Chan-Hee; Hwang, Nong-Moon

    2013-12-01

    Using parallel three-dimensional Monte Carlo simulations, we investigated the effects of precipitates and sub-boundaries on abnormal grain growth (AGG) of Goss grains based on real orientation data of primary recrystallized Fe-3%Si steel. The simulations showed that AGG occurred in the presence of precipitates which inhibited the grain growth of matrix grains, whereas it did not in the absence of precipitates. The role of precipitates in enhancing AGG is to maintain a relatively high fraction of high energy boundaries between matrix grains, which increases the probability of sub-boundary-enhanced solid-state wetting of an abnormally growing grain. The microstructure evolved by the simulation could reproduce many realistic features of abnormally growing grains, such as the formation of island and peninsular grains and merging of abnormally growing grains which appeared to be separated initially on the cross-section.

  7. Effects of abnormal temperature and starvation on the internal defense system of the schistosome-transmitting snail Biomphalaria glabrata.

    PubMed

    Nelson, Molly K; Cruz, Brandon C; Buena, Kevin L; Nguyen, Hai; Sullivan, John T

    2016-07-01

    Climate change may affect the internal defense system (IDS) of freshwater snails, and as a result their capacity to transmit disease. We examined effects of short-term exposure to supra- and sub-optimal temperatures or starvation on 3 parameters of the IDS of the schistosome-resistant Salvador strain of Biomphalaria glabrata - hemocyte concentrations, cell division in the amebocyte-producing organ (APO), and resistance to infection with Schistosoma mansoni. Adult snails were exposed to 1 of 3 temperatures, 20°C, 27°C (controls), or 33°C, for 1 or 2weeks, with food. A fourth group was maintained at 27°C, but without food. Compared to the controls, starved snails had significantly higher hemocyte counts at both 1 and 2weeks, although mitotic activity in the APO was significantly lower at both time periods. Exposure to 20°C or 33°C for 1 or 2weeks did not affect hemocyte numbers. However, APO mitotic activity in snails exposed to 20°C was significantly higher at both 1 and 2weeks, whereas mitotic activity in snails exposed to 33°C was significantly lower at 1week but normal at 2weeks. None of the treatments altered the resistance phenotype of Salvador snails. In a follow-up experiment, exposure to 33°C for 4-5h, a treatment previously reported to both induce expression of heat shock proteins (Hsps) and abrogate resistance to infection, caused immediate upregulation of Hsp 70 and Hsp 90 expression, but did not alter resistance, and Hsp expression levels returned to baseline after 2weeks at 33°C. Results of this study indicate that abnormal environmental conditions can have both stimulatory and inhibitory effects on the IDS in adult B. glabrata, and that some degree of acclimation to abnormal temperatures may occur. PMID:27261059

  8. Role of domain walls in the abnormal photovoltaic effect in BiFeO3

    PubMed Central

    Bhatnagar, Akash; Roy Chaudhuri, Ayan; Heon Kim, Young; Hesse, Dietrich; Alexe, Marin

    2013-01-01

    Recently, the anomalous photovoltaic (PV) effect in BiFeO3 (BFO) thin films, which resulted in open circuit voltages (Voc) considerably larger than the band gap of the material, has generated a revival of the entire field of photoferroelectrics. Here, via temperature-dependent PV studies, we prove that the bulk photovoltaic (BPV) effect, which has been studied in the past for many non-centrosymmetric materials, is at the origin of the anomalous PV effect in BFO films. Moreover, we show that irrespective of the measurement geometry, Voc as high as 50 V can be achieved by controlling the conductivity of domain walls (DW). We also show that photoconductivity of the DW is markedly higher than in the bulk of BFO.

  9. Strengthening Effective Government-Citizen Connections through Greater Civic Engagement.

    ERIC Educational Resources Information Center

    Kirlin, John J.; Kirlin, Mary K.

    2002-01-01

    Citizens are more trusting of government since the terrorist attacks of September 11, 2001, but their civic behaviors are little changed. Theoretical and empirical analyses suggest that motivation, skills, and network connections contribute to increased civic engagement, yet responses have not addressed these factors. (Contains 32 references.)…

  10. Connect: An Effective Community-Based Youth Suicide Prevention Program

    ERIC Educational Resources Information Center

    Bean, Gretchen; Baber, Kristine M.

    2011-01-01

    Youth suicide prevention is an important public health issue. However, few prevention programs are theory driven or systematically evaluated. This study evaluated Connect, a community-based youth suicide prevention program. Analysis of pre and posttraining questionnaires from 648 adults and 204 high school students revealed significant changes in…

  11. The Brain Effective Connectivity of Chinese during Rhyming Task.

    PubMed

    Zhu, Linlin; Niu, Zhendong; Nie, Yaoxin; Yang, Yang; Li, Ke; Jin, Zhen; Wei, Jieyao

    2016-01-01

    With regard to brain language processing, the activation patterns have been well studied, and recently there are great interest in the connectivity models. The crucial brain areas for phonological processing involves left inferior frontal gyrus (LIFG), left inferior parietal lobule (LIPL) and left posterior middle temporal gyrus (LpMTG). Specially in Chinese processing, the left middle frontal gyrus (LMFG) is considered as an essential region. However, the connectivity pattern among these brain areas is not well understood. In this study, a rhyming experiment of Chinese was conducted, and the Dynamic causal modeling (DCM) and the Bayesian model selection (BMS) were used to examine the interaction between brain regions and choose the best model for rhyming task of Chinese. By examining the interactions, it was found that LMFG exerted inhibitory modulation on LIPL and LIFG; the phonological processing enhanced the connection from LIPL to LIFG and LMFG, which suggested the important roles of these connections for the increased phonological load; And LpMTG modulated LIFG and LMFG negatively, and LIPL positively under rhyming judgment task. PMID:27583349

  12. Antioxidants have a rapid and long-lasting effect on neuritic abnormalities in APP:PS1 mice.

    PubMed

    Garcia-Alloza, Monica; Borrelli, Laura A; Hyman, Bradley T; Bacskai, Brian J

    2010-12-01

    Senile plaques are a major pathological hallmark of Alzheimer's disease (AD). Compelling evidence suggests that senile plaques lead to structural alterations of neuronal processes and that local toxicity may be mediated by increased oxidative stress. Anti-oxidant therapy can alleviate the neuronal abnormalities in APP mice, but the time-course of this beneficial effect is unknown. We used multiphoton microscopy to assess in vivo the characteristics of antioxidant treatment on senile plaques and neurites in AD model mice (APPswe/PS1dE9). We observed that α-phenyl-N-tert-butyl nitrone (PBN), Ginkgo biloba extract (EGb 761) and Trolox had no effect on the size of existing senile plaques. However, all anti-oxidants had a straightening effect on curved neurites. This effect was detected as soon as 4 days after commencing the treatment, and was maintained after 1 month of daily treatment, with no further increase in the effect. The straightening of neurites persisted 15 days after stopping the treatment. These data indicate that neuronal plasticity is fast and still active in adult animals, and suggest that amelioration of the neuritic distortions associated with senile plaques with antioxidants is both rapid and long lasting. PMID:19124175

  13. Effects of homeostatic constraints on associative memory storage and synaptic connectivity of cortical circuits

    PubMed Central

    Chapeton, Julio; Gala, Rohan; Stepanyants, Armen

    2015-01-01

    The impact of learning and long-term memory storage on synaptic connectivity is not completely understood. In this study, we examine the effects of associative learning on synaptic connectivity in adult cortical circuits by hypothesizing that these circuits function in a steady-state, in which the memory capacity of a circuit is maximal and learning must be accompanied by forgetting. Steady-state circuits should be characterized by unique connectivity features. To uncover such features we developed a biologically constrained, exactly solvable model of associative memory storage. The model is applicable to networks of multiple excitatory and inhibitory neuron classes and can account for homeostatic constraints on the number and the overall weight of functional connections received by each neuron. The results show that in spite of a large number of neuron classes, functional connections between potentially connected cells are realized with less than 50% probability if the presynaptic cell is excitatory and generally a much greater probability if it is inhibitory. We also find that constraining the overall weight of presynaptic connections leads to Gaussian connection weight distributions that are truncated at zero. In contrast, constraining the total number of functional presynaptic connections leads to non-Gaussian distributions, in which weak connections are absent. These theoretical predictions are compared with a large dataset of published experimental studies reporting amplitudes of unitary postsynaptic potentials and probabilities of connections between various classes of excitatory and inhibitory neurons in the cerebellum, neocortex, and hippocampus. PMID:26150784

  14. [Emotion Disorders and Abnormal Perspiration].

    PubMed

    Umeda, Satoshi

    2016-08-01

    This article reviewed the relationship between emotional disorders and abnormal perspiration. First, I focused on local brain areas related to emotional processing, and summarized the functions of the emotional network involving those local areas. Functional disorders followed by the damage in the amygdala, orbitofrontal cortex, and insular cortex were reviewed, including related abnormal perspiration. I then addressed the mechanisms of how autonomic disorders influence emotional processing. Finally, possible future directions for integrated understanding of the connection between neural activities and bodily reactions were discussed. PMID:27503817

  15. Matching structural, effective, and functional connectivity: a comparison between structural equation modeling and ancestral graphs.

    PubMed

    Bringmann, Laura F; Scholte, H Steven; Waldorp, Lourens J

    2013-01-01

    In this study, we examined the accuracy of ancestral graphs (AGs) to study effective connectivity in the brain. Unlike most other methods that estimate effective connectivity, an AG is able to explicitly model missing brain regions in a network model. We compared AGs with the conventional structural equation models (SEM). We used both methods to estimate connection strengths between six regions of interest of the visual cortex based on functional magnetic resonance imaging data of a motion perception task. In order to examine which method is more accurate to estimate effective connectivity, we compared the connection strengths of the AG and SEM models with connection probabilities resulting from probabilistic tractography obtained from diffusion tensor images. This was done by correlating the connection strengths of the best fitting AG and SEM models with the connection probabilities of the probabilistic tractography models. We show that, in general, AGs result in more accurate models to estimate effective connectivity than SEM. The reason for this is that missing regions are taken into account when modeling with AG but not when modeling with SEM: AG can be used to explicitly test the assumption of missing regions. If the set of regions is complete, SEM and AG perform about equally well. PMID:23662916

  16. Adolescent Binge Drinking Linked to Abnormal Spatial Working Memory Brain Activation: Differential Gender Effects

    PubMed Central

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

    2011-01-01

    Background 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. Methods 40 binge drinkers (13 females, 27 males) and 55 controls (24 females, 31 males) ages 16 to 19, completed neuropsychological testing, substance use interviews, and a spatial working memory task (SWM) during functional magnetic resonance imaging (fMRI). Results Significant binge drinking status x gender interactions were found (p<.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 (ps<.025). For male binge drinkers, greater activation was linked to better spatial performance (p<.025). Conclusion Binge drinking during adolescence is associated with gender-specific differences in frontal, temporal, and cerebellar brain activation during a SWM task, which in turn relate to cognitive performance. Activation correlates with neuropsychological performance, strengthening the argument that BOLD activation is both 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

  17. Gap Effect Abnormalities during a Visually Guided Pro-Saccade Task in Children with Attention Deficit Hyperactivity Disorder

    PubMed Central

    Taniike, Masako; Mohri, Ikuko; Kobashi, Syoji; Tachibana, Masaya; Kobayashi, Yasushi; Kitamura, Yuri

    2015-01-01

    Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder that starts in early childhood and has a comprehensive impact on psychosocial activity and education as well as general health across the lifespan. Despite its prevalence, the current diagnostic criteria for ADHD are debated. Saccadic eye movements are easy to quantify and may be a quantitative biomarker for a wide variety of neurological and psychiatric disorders, including ADHD. The goal of this study was to examine whether children with ADHD exhibit abnormalities during a visually guided pro-saccadic eye-movement and to clarify the neurophysiological mechanisms associated with their behavioral impairments. Thirty-seven children with ADHD (aged 5–11 years) and 88 typically developing (TD) children (aged 5–11 years) were asked to perform a simple saccadic eye-movement task in which step and gap conditions were randomly interleaved. We evaluated the gap effect, which is the difference in the reaction time between the two conditions. Children with ADHD had a significantly longer reaction time than TD children (p < 0.01) and the gap effect was markedly attenuated (p < 0.01). These results suggest that the measurement of saccadic eye movements may provide a novel method for evaluating the behavioral symptoms and clinical features of ADHD, and that the gap effect is a potential biomarker for the diagnosis of ADHD in early childhood. PMID:26018057

  18. Effective Connectivity Modeling for fMRI: Six Issues and Possible Solutions Using Linear Dynamic Systems

    PubMed Central

    Smith, Jason F.; Pillai, Ajay; Chen, Kewei; Horwitz, Barry

    2012-01-01

    Analysis of directionally specific or causal interactions between regions in functional magnetic resonance imaging (fMRI) data has proliferated. Here we identify six issues with existing effective connectivity methods that need to be addressed. The issues are discussed within the framework of linear dynamic systems for fMRI (LDSf). The first concerns the use of deterministic models to identify inter-regional effective connectivity. We show that deterministic dynamics are incapable of identifying the trial-to-trial variability typically investigated as the marker of connectivity while stochastic models can capture this variability. The second concerns the simplistic (constant) connectivity modeled by most methods. Connectivity parameters of the LDSf model can vary at the same timescale as the input data. Further, extending LDSf to mixtures of multiple models provides more robust connectivity variation. The third concerns the correct identification of the network itself including the number and anatomical origin of the network nodes. Augmentation of the LDSf state space can identify additional nodes of a network. The fourth concerns the locus of the signal used as a “node” in a network. A novel extension LDSf incorporating sparse canonical correlations can select most relevant voxels from an anatomically defined region based on connectivity. The fifth concerns connection interpretation. Individual parameter differences have received most attention. We present alternative network descriptors of connectivity changes which consider the whole network. The sixth concerns the temporal resolution of fMRI data relative to the timescale of the inter-regional interactions in the brain. LDSf includes an “instantaneous” connection term to capture connectivity occurring at timescales faster than the data resolution. The LDS framework can also be extended to statistically combine fMRI and EEG data. The LDSf framework is a promising foundation for effective connectivity

  19. Effective Connectivity Modeling for fMRI: Six Issues and Possible Solutions Using Linear Dynamic Systems.

    PubMed

    Smith, Jason F; Pillai, Ajay; Chen, Kewei; Horwitz, Barry

    2011-01-01

    Analysis of directionally specific or causal interactions between regions in functional magnetic resonance imaging (fMRI) data has proliferated. Here we identify six issues with existing effective connectivity methods that need to be addressed. The issues are discussed within the framework of linear dynamic systems for fMRI (LDSf). The first concerns the use of deterministic models to identify inter-regional effective connectivity. We show that deterministic dynamics are incapable of identifying the trial-to-trial variability typically investigated as the marker of connectivity while stochastic models can capture this variability. The second concerns the simplistic (constant) connectivity modeled by most methods. Connectivity parameters of the LDSf model can vary at the same timescale as the input data. Further, extending LDSf to mixtures of multiple models provides more robust connectivity variation. The third concerns the correct identification of the network itself including the number and anatomical origin of the network nodes. Augmentation of the LDSf state space can identify additional nodes of a network. The fourth concerns the locus of the signal used as a "node" in a network. A novel extension LDSf incorporating sparse canonical correlations can select most relevant voxels from an anatomically defined region based on connectivity. The fifth concerns connection interpretation. Individual parameter differences have received most attention. We present alternative network descriptors of connectivity changes which consider the whole network. The sixth concerns the temporal resolution of fMRI data relative to the timescale of the inter-regional interactions in the brain. LDSf includes an "instantaneous" connection term to capture connectivity occurring at timescales faster than the data resolution. The LDS framework can also be extended to statistically combine fMRI and EEG data. The LDSf framework is a promising foundation for effective connectivity analysis

  20. The Effect of Prolonged Culture of Chromosomally Abnormal Human Embryos on The Rate of Diploid Cells

    PubMed Central

    Bazrgar, Masood; Gourabi, Hamid; Eftekhari-Yazdi, Poopak; Vazirinasab, Hamed; Fakhri, Mostafa; Hassani, Fatemeh; Chehrazi, Mohamad; Valojerdi, Mojtaba Rezazadeh

    2016-01-01

    Background A decrease in aneuploidy rate following a prolonged co-culture of human blastocysts has been reported. As co-culture is not routinely used in assisted reproductive technology, the present study aimed to evaluate the effect of the prolonged single culture on the rate of diploid cells in human embryos with aneuploidies. Materials and Methods In this cohort study, we used fluorescence in situ hybridi- zation (FISH) to reanalyze surplus blastocysts undergoing preimplantation genetic diagnosis (PGD) on day 3 postfertilization. They were randomly studied on days 6 or 7 following fertilization. Results Of the 30 analyzed blastocysts, mosaicism was observed in 26(86.6%), while 2(6.7%) were diploid, and 2(6.7%) were triploid. Of those with mosaicism, 23(88.5%) were determined to be diploid-aneuploid and 3(11.5%) were aneuploid mosaic. The total frequency of embryos with more than 50% diploid cells was 33.3% that was lower on day 7 in comparison with the related value on day 6 (P<0.05); however, there were no differences when the embryos were classified according to maternal age, blastocyst developmental stage, total cell number on day 3, and embryo quality. Conclusion Although mosaicism is frequently observed in blastocysts, the prolonged single culture of blastocysts does not seem to increase the rate of normal cells. PMID:26985346

  1. Surface antigen expression in chronic lymphocytic leukemia: clustering analysis, interrelationships and effects of chromosomal abnormalities.

    PubMed

    Hulkkonen, J; Vilpo, L; Hurme, M; Vilpo, J

    2002-02-01

    Chronic lymphocytic leukemia (CLL) is a phenotypically distinguishable form of B-lymphoid leukemias. The regularity of surface membrane antigen expression patterns, their interrelationships as well as the effects of the three frequent chromosomal aberrations, ie 11q deletion, 13q deletion and trisomy 12, were investigated in 35 classic CLL cases by flow cytometry. The two-way cluster analysis of 31 individual antigens revealed three expression patterns: (1) most cells in most cases positive (CD5, CD19, CD20, CD23, CD27, CD40, CD45, CD45RA); (2) most cells in most cases negative (CD10, CD14, CD34, CD122, CD154, mIgG); and (3) a mixed pattern with a variable number of positive cases and a variable percentage of positive cells in individual cases (CD11c, CD21, CD22, CD25, CD38, CD45RO, CD79b, CD80, CD95, CD124, CD126, CD130, FMC7, mIgD, mIgkappa, mIglambda, mIgM). The expressions of several antigens were strongly interdependent, even when antigens belonged to entirely different gene families. Such antigen pairs were: CD11c/CD21; CD19/CD45; CD19/CD79b; CD22/CD45RA; CD23/Igkappa; CD25/mIgM; CD27/CD45; CD45/CD79b; CD45RA/Igkappa. In contrast, the expression of some antigens was mutually exclusive, the best examples being CD45RA/CD45RO, CD38/CD80 and CD45RA/CD80. Deletion of chromosome arm 11q attenuated expression of splicing variant CD45RA, but enhanced CD45RO expression. In contrast, cases of trisomy 12 were associated with enhanced CD45RA and attenuated CD45RO expression. Similarly, trisomy 12 was associated with enhanced CD27 and mIgkappa expression. The variable levels of signaling surface membrane antigens, their interactions and interference by genetic aberrations are likely to affect the clinical progression and drug response of CLL. PMID:11840283

  2. Analytical investigation of the effects of lateral connections on the accuracy of population coding

    NASA Astrophysics Data System (ADS)

    Oizumi, Masafumi; Miura, Keiji; Okada, Masato

    2010-05-01

    We studied how lateral connections affect the accuracy of a population code by using a model of orientation selectivity in the primary visual cortex. Investigating the effects of lateral connections on population coding is a complex problem because these connections simultaneously change the shape of tuning curves and correlations between neurons. Both of these changes caused by lateral connections have to be taken into consideration to correctly evaluate their effects. We propose a theoretical framework for analytically computing the Fisher information, which measures the accuracy of a population code, in stochastic spiking neuron models with refractory periods. Within our framework, we accurately evaluated both the changes in tuning curves and correlations caused by lateral connections and their effects on the Fisher information. We found that their effects conflicted with each other and the answer to whether or not the lateral connections increased the Fisher information strongly depended on the intrinsic properties of the model neuron. By systematically changing the coupling strengths of excitations and inhibitions, we found the parameter regions of lateral connectivities where sharpening of tuning curves through Mexican-hat connectivities led to an increase in information, which is in contrast to some previous findings.

  3. Potential confounding effects of benzyl alcohol as a formulation excipient support the elimination of the abnormal toxicity test from pharmacopoeias.

    PubMed

    Xie, Jianxun; Ottaviani, Giorgio; Sun, Kai; Lu, Mingqiu; Wu, Xiaoqin; Huang, Sunfeng; Bopst, Martin

    2015-11-01

    Benzyl alcohol is an excipient used in many drugs as a stabilizer. Depending on the amount present in drug formulations there might be confounding findings in the Abnormal Toxicity Test (ATT). The ATT is utilized as a quality control (QC) release test to detect extraneous contaminants according to national pharmacopoeias. Our study assessed the effects of benzyl alcohol as defined in ATT designs. This study - the first thorough evaluation of the confounding effects of benzyl alcohol on the ATT - was conducted in relation to particular health authority questions and was part of the root-cause analyses resulting from some transient behavioral findings observed in the test. Two strains of mice, CD-1 & Kunming, plus Hartley guinea pigs were administered intraperitoneally (ip), subcutaneously (sc), or intravenously (iv) with benzyl alcohol at dose level defined in the ATT design. In both mice and guinea pigs, only after ip administration, minimal behavioral changes were observed transiently within 2-3 min after administration. Therefore, the presence of benzyl alcohol in the product batch may confound the ATT results. This study provides further evidence to question the validity of the ATT for its intended use. PMID:26449397

  4. Sperm abnormalities induced by pre-pubertal exposure to cyclophosphamide are effectively mitigated by Moringa oleifera leaf extract.

    PubMed

    Nayak, G; Vadinkar, A; Nair, S; Kalthur, S G; D'Souza, A S; Shetty, P K; Mutalik, S; Shetty, M M; Kalthur, G; Adiga, S K

    2016-03-01

    Moringa oleifera L. is a medicinal plant with potential antioxidant property. This study was aimed at investigating the chemoprotective effect of Moringa oleifera leaf extract (MOE) on cyclophosphamide (CP)-induced testicular toxicity. Two-week-old male Swiss albino mice were intraperitoneally injected with phosphate-buffered saline, 50 mg kg(-1) of CP and 25 mg kg(-1) of MOE. In combination treatment, mice were injected with 25 mg kg(-1) of MOE 24 h prior to CP injection, 24 h prior and post-CP injection and 24 h post-CP injection for 5 consecutive days (10 mg kg(-1) ). Six weeks later, mice were sacrificed to assess epididymal sperm parameters. MOE alone did not have any significant effect on sperm parameters. However, acute injection of CP resulted in significant decline in motility (P < 0.001), increase in head abnormality (P < 0.01) and DNA damage (P < 0.05). Combining MOE with CP increased the sperm density, motility and reduced head defect and DNA damage, irrespective of the schedule and dosage of MOE. Administration of MOE prior to CP significantly elevated the level of superoxide dismutase and catalase with concomitant decrease in lipid peroxidation in the testicular tissue. In conclusion, MOE may have potential benefit in reducing the loss of male gonadal function following chemotherapy. PMID:25904411

  5. Beneficial effects of sodium butyrate in 6-OHDA induced neurotoxicity and behavioral abnormalities: Modulation of histone deacetylase activity.

    PubMed

    Sharma, Sorabh; Taliyan, Rajeev; Singh, Sumel

    2015-09-15

    Parkinson's disease (PD) is the second most common neurodegenerative disorder. Recent studies have investigated the involvement of epigenetic modifications in PD. Histone deacetylase (HDAC) inhibitors have been reported to be beneficial in cognitive and motor deficit states. The present study was designed to investigate the effect of sodium butyrate, a HDAC inhibitor in 6-hydroxydopamine (6-OHDA) - induced experimental PD like symptoms in rats. To produce motor deficit, 6-OHDA was administered unilaterally in the right medial forebrain bundle. Three weeks after 6-OHDA administration, the rats were challenged with apomorphine. Following this, the animals were treated with sodium butyrate (150 and 300 mg/kg i.p.) once daily for 14 days. Movement abnormalities were assessed by battery of behavioral tests. Biochemically, oxidative stress markers, neuroinflammation and dopamine were measured in striatal brain homogenate. Further, to explore the molecular mechanism(s), we measured the level of global H3 histone acetylation and brain derived neurotrophic factor (BDNF). 6-OHDA administration results in significant motor deficit along with reduction in striatal dopamine level. 6-OHDA treated rats showed elevated oxidative stress and neuroinflammatory markers. Treatment with sodium butyrate results in significant attenuation of motor deficits and increased striatal dopamine level. Moreover, sodium butyrate treatment attenuated the oxidative stress and neuroinflammatory markers. These effects occur concurrently with increased global H3 histone acetylation and BDNF levels. Thus, the observed results of the present study are indicative for the therapeutic potential of HDAC inhibitors in PD. PMID:26048426

  6. Developmental abnormalities and neurotoxicological effects of CuO NPs on the black sea urchin Arbacia lixula by embryotoxicity assay.

    PubMed

    Maisano, Maria; Cappello, Tiziana; Catanese, Eva; Vitale, Valeria; Natalotto, Antonino; Giannetto, Alessia; Barreca, Davide; Brunelli, Elvira; Mauceri, Angela; Fasulo, Salvatore

    2015-10-01

    The embryotoxicity of CuO NPs was evaluated in the black sea urchin Arbacia lixula embryos, by using 24-well plates. Fertilized eggs were exposed to five doses of CuO NPs ranging from 0.07 to 20 ppb, until pluteus stage. CuO NPs suspensions in artificial seawater formed agglomerates of 80-200 nm size, and copper uptake was 2.5-fold up in larvae exposed to high NP concentrations in respect to control. Developmental delay and morphological alteration, including skeletal abnormalities, were observed, as well as impairment in cholinergic and serotonergic nervous systems. These findings suggest the potential of CuO NPs to interfere with the normal neurotransmission pathways, thus affecting larval morphogenesis. Overall, the embryotoxicity tests are effective for evaluation of nanoparticle effects on the health of aquatic biota. Furthermore, as the black sea urchin A. lixula demonstrated to be vulnerable to NP exposure, it may be a valid bioindicator in marine biomonitoring and ecotoxicological programmes. PMID:26026240

  7. Pore connectivity effects on solute transport in rocks

    SciTech Connect

    Hu, Qinhong; Ewing, Robert P.

    2001-11-30

    Retardation of nuclear contaminants in rock matrices can lead to long retention times, allowing substantial radionuclide decay prior to eventual release. Imbibition and diffusion into the rock matrix can move contaminants away from an active fracture, thereby contributing to their retardation. However, diffusive transport in some rocks may behave anomalously because of their sparsely connected porespace, in contrast to diffusion in rocks with denser pore connections. We examined imbibition of weakly sorbing tracers into welded tuff and Indiana sandstone, and water imbibition into metagraywacke and Berea sandstone. Tuff samples were initially equilibrated to 12% and 76% water (v/v) within controlled humidity chambers, while the other rocks were air-dried. For imbibition, one face was exposed to water, with or without tracer, and uptake was measured over time. Following imbibition, tracer concentration measurements were made at fine (1 mm) increments. Three anomalous results were observed: (1) Indiana sandstone and metagraywacke showed mass of imbibed water scaling as time{sup 0.26}, while tuff and Berea sandstone showed the more classical scaling with time{sup 0.5}; (2) tracer movement into dry (2% initial saturation) Indiana sandstone showed a dispersion pattern similar to that expected during tracer movement into moist (76% initial saturation) tuff; and (3) tracer concentrations at the inlet face of the tuff sample were approximately twice those deeper inside the sample. The experiment was then modeled using random walk methods on a 3-D lattice with different values of pore coordination. Network model simulations that used a pore coordination of 1.49 for Indiana sandstone and 1.56 for metagraywacke showed similar temporal scaling, a result of their porespace being close to the percolation threshold. Tracer concentration profiles in Indiana sandstone and tuff were closely matched by simulations that used pore coordinations of 1.49 and 1.68, respectively, because of

  8. Impaired Bottom-Up Effective Connectivity Between Amygdala and Subgenual Anterior Cingulate Cortex in Unmedicated Adolescents with Major Depression: Results from a Dynamic Causal Modeling Analysis.

    PubMed

    Musgrove, Donald R; Eberly, Lynn E; Klimes-Dougan, Bonnie; Basgoze, Zeynep; Thomas, Kathleen M; Mueller, Bryon A; Houri, Alaa; Lim, Kelvin O; Cullen, Kathryn R

    2015-12-01

    Major depressive disorder (MDD) is a significant contributor to lifetime disability and frequently emerges in adolescence, yet little is known about the neural mechanisms of MDD in adolescents. Dynamic causal modeling (DCM) analysis is an innovative tool that can shed light on neural network abnormalities. A DCM analysis was conducted to test several frontolimbic effective connectivity models in 27 adolescents with MDD and 21 healthy adolescents. The best neural model for each person was identified using Bayesian model selection. The findings revealed that the two adolescent groups fit similar optimal neural models. The best across-groups model was then used to infer upon both within-group and between-group tests of intrinsic and modulation parameters of the network connections. First, for model validation, within-group tests revealed robust evidence for bottom-up connectivity, but less evidence for strong top-down connectivity in both groups. Second, we tested for differences between groups on the validated parameters of the best model. This revealed that adolescents with MDD had significantly weaker bottom-up connectivity in one pathway, from amygdala to sgACC (p=0.008), than healthy controls. This study provides the first examination of effective connectivity using DCM within neural circuitry implicated in emotion processing in adolescents with MDD. These findings aid in advancing understanding the neurobiology of early-onset MDD during adolescence and have implications for future research investigating how effective connectivity changes across contexts, with development, over the course of the disease, and after intervention. PMID:26050933

  9. Conditional Granger Causality Analysis of Effective Connectivity during Motor Imagery and Motor Execution in Stroke Patients

    PubMed Central

    Wang, Li; Zhang, Jingna; Zhang, Ye; Yan, Rubing; Liu, Hongliang; Qiu, Mingguo

    2016-01-01

    Aims. Motor imagery has emerged as a promising technique for the improvement of motor function following stroke, but the mechanism of functional network reorganization in patients during this process remains unclear. The aim of this study is to evaluate the cortical motor network patterns of effective connectivity in stroke patients. Methods. Ten stroke patients with right hand hemiplegia and ten normal control subjects were recruited. We applied conditional Granger causality analysis (CGCA) to explore and compare the functional connectivity between motor execution and motor imagery. Results. Compared with the normal controls, the patient group showed lower effective connectivity to the primary motor cortex (M1), the premotor cortex (PMC), and the supplementary motor area (SMA) in the damaged hemisphere but stronger effective connectivity to the ipsilesional PMC and M1 in the intact hemisphere during motor execution. There were tighter connections in the cortical motor network in the patients than in the controls during motor imagery, and the patients showed more effective connectivity in the intact hemisphere. Conclusions. The increase in effective connectivity suggests that motor imagery enhances core corticocortical interactions, promotes internal interaction in damaged hemispheres in stroke patients, and may facilitate recovery of motor function. PMID:27200373

  10. Effect of Thermoelectric Modules' Topological Connection on Automotive Exhaust Heat Recovery System

    NASA Astrophysics Data System (ADS)

    Deng, Y. D.; Zheng, S. J.; Su, C. Q.; Yuan, X. H.; Yu, C. G.; Wang, Y. P.

    2016-03-01

    In automotive exhaust-based thermoelectric generators (AETEGs), a certain number of thermoelectric modules are connected in series and/or parallel to recover energy from exhaust gas, which provides a way to improve fuel efficiency of the vehicle. Because of the temperature distribution on the surfaces of heat exchanger, several types of modules are planned for use in an AETEG; however, property disparities among modules exist and wire resistance cannot be neglected in practical application, so experiments have been carried out to research effects of the two factors on the maximum output power of series and parallel connection. The performance of series and parallel connections have been characterized, and mathematic models have been built to analyze and predict the performance of each connection. Experiments and theoretical analysis reveal that parallel connection shows a better performance than series connection when large differences of Seebeck coefficient and resistivity exist. However, wire resistance will cause more significant power dissipation in parallel connection. The authors believe the research presented in this paper is the first to carry out an examination of the impact of module property disparity and wire resistance on the output power of an array of thermoelectric modules connected in series and parallel, which provides a reference for choosing module connection in AETEGs.

  11. Effective Connectivity within Human Primary Visual Cortex Predicts Interindividual Diversity in Illusory Perception

    PubMed Central

    Schwarzkopf, D. Samuel; Lutti, Antoine; Li, Baojuan; Kanai, Ryota; Rees, Geraint

    2013-01-01

    Visual perception depends strongly on spatial context. A classic example is the tilt illusion where the perceived orientation of a central stimulus differs from its physical orientation when surrounded by tilted spatial contexts. Here we show that such contextual modulation of orientation perception exhibits trait-like interindividual diversity that correlates with interindividual differences in effective connectivity within human primary visual cortex. We found that the degree to which spatial contexts induced illusory orientation perception, namely, the magnitude of the tilt illusion, varied across healthy human adults in a trait-like fashion independent of stimulus size or contrast. Parallel to contextual modulation of orientation perception, the presence of spatial contexts affected effective connectivity within human primary visual cortex between peripheral and foveal representations that responded to spatial context and central stimulus, respectively. Importantly, this effective connectivity from peripheral to foveal primary visual cortex correlated with interindividual differences in the magnitude of the tilt illusion. Moreover, this correlation with illusion perception was observed for effective connectivity under tilted contextual stimulation but not for that under iso-oriented contextual stimulation, suggesting that it reflected the impact of orientation-dependent intra-areal connections. Our findings revealed an interindividual correlation between intra-areal connectivity within primary visual cortex and contextual influence on orientation perception. This neurophysiological-perceptual link provides empirical evidence for theoretical proposals that intra-areal connections in early visual cortices are involved in contextual modulation of visual perception. PMID:24285885

  12. Large-scale experimental landscapes reveal distinctive effects of patch shape and connectivity on arthropod communities.

    SciTech Connect

    Orrock, John, L.; Curler, Gregory, R.; Danielson, Brent, J.; Coyle, David. R.

    2011-09-14

    The size, shape, and isolation of habitat patches can affect organism behavior and population dynamics, but little is known about the relative role of shape and connectivity in affecting ecological communities at large spatial scales. Using six sampling sessions from July 2001 until August 2002, we collected 33,685 arthropods throughout seven 12-ha experimental landscapes consisting of clear-cut patches surrounded by a matrix of mature pine forest. Patches were explicitly designed to manipulate connectivity (via habitat corridors) independently of area and edge effects. We found that patch shape, rather than connectivity, affected ground-dwelling arthropod richness and beta diversity (i.e. turnover of genera among patches). Arthropod communities contained fewer genera and exhibited less turnover in high-edge connected and high-edge unconnected patches relative to low-edge unconnected patches of similar area. Connectivity, rather than patch shape, affected the evenness of ground-dwelling arthropod communities; regardless of patch shape, high-edge connected patches had lower evenness than low- or high-edge unconnected patches. Among the most abundant arthropod orders, increased richness in low-edge unconnected patches was largely due to increased richness of Coleoptera, whereas Hymenoptera played an important role in the lower evenness in connected patches and patterns of turnover. These findings suggest that anthropogenic habitat alteration can have distinct effects on ground-dwelling arthropod communities that arise due to changes in shape and connectivity. Moreover, this work suggests that corridors, which are common conservation tools that change both patch shape and connectivity, can have multiple effects on arthropod communities via different mechanisms, and each effect may alter components of community structure.

  13. A connectomics approach combining structural and effective connectivity assessed by intracranial electrical stimulation.

    PubMed

    Donos, Cristian; Mălîia, Mihai Dragoş; Mîndruţă, Ioana; Popa, Irina; Ene, Mirela; Bălănescu, Bogdan; Ciurea, Ana; Barborica, Andrei

    2016-05-15

    In the context of the human brain, the term "connectivity" can refer to structural, functional or effective connectivity. Intracranial electrical stimulation is perhaps the most direct way of investigating the effective connectivity. We propose a method of mapping the effective connectivity, revealed by the electrical stimulation of brain structures, over the structural connectome (SC), obtained through diffusion spectrum imaging (DSI), to form a structural-effective connectome (SEC). A number of 24 patients with refractory epilepsy were implanted with depth electrodes for pre-surgical evaluation. Effective connectivity was assessed by analyzing the responses to single pulse electrical stimulation (SPES). Stimulation pulses having variable amplitude were applied to each pair of adjacent contacts and responses evoked by stimulation were recorded from other contacts located in other brain areas. Early responses (10-110 ms) on the stimulation-activated contacts located outside the epileptogenic zone were averaged for each patient, resulting in a patient-level physiological effective connectome (EC). The population level EC is computed by averaging the connections of the individual ECs, on a structure by structure basis. A fiber activation factor is used to weight the number of fibers connecting a pair of structures in the SC by its corresponding normalized EC value. The resulting number of effectively activated fibers describes the directional connection strength between two structures in the SEC. A physiological SEC comprising directional connections between 70 segmented brain areas in both hemispheres, was obtained by inclusion of structures outside the epileptogenic zone only. Over the entire structure set, the Spearman's correlation coefficient ρ between the number of fibers extracted from the DSI Atlas and the normalized RMS responses to SPES was ρ=0.21 (p<0.001), while Kendall's tau coefficients ranged -0.52-0.44 (p<0.05). The physiological structural-effective

  14. What are the Effects of Severe Visual Impairment on the Cortical Organization and Connectivity of Primary Visual Cortex?

    PubMed Central

    Larsen, DeLaine D.; Luu, Julie D.; Burns, Marie E.; Krubitzer, Leah

    2009-01-01

    The organization and connections of the primary visual area (V1) were examined in mice that lacked functional rods (Gnat−/−), but had normal cone function. Because mice are nocturnal and rely almost exclusively on rod vision for normal behaviors, the Gnat−/− mice used in the present study are considered functionally blind. Our goal was to determine if visual cortex is reorganized in these mice, and to examine the neuroanatomical connections that may subserve reorganization. We found that most neurons in V1 responded to auditory, or some combination of auditory, somatosensory, and/or visual stimulation. We also determined that cortical connections of V1 in Gnat−/− mice were similar to those in normal animals, but even in normal animals, there is sparse input from auditory cortex (AC) to V1. An important observation was that most of the subcortical inputs to V1 were from thalamic nuclei that normally project to V1 such as the lateral geniculate (LG), lateral posterior (LP), and lateral dorsal (LD) nuclei. However, V1 also received some abnormal subcortical inputs from the anterior thalamic nuclei, the ventral posterior, the ventral lateral and the posterior nuclei. While the vision generated from the small number of cones appears to be sufficient to maintain most of the patterns of normal connectivity, the sparse abnormal thalamic inputs to VI, existing inputs from AC, and possibly abnormal inputs to LG and LP may be responsible for generating the alterations in the functional organization of V1. PMID:20057935

  15. Defining an Effective Damage Zone from the Topological Connectivity of Deformation Bands

    NASA Astrophysics Data System (ADS)

    Gwon, S.; Edwards, P.; Sanderson, D. J.; Kim, Y. S.

    2015-12-01

    The length, intensity, and geometrical and topological characteristics of the deformation bands in the damage zone have been analysed along the length of the Bartlett Fault, Utah and through its linked section to the Moab Fault. Samples were also collected at each location for porosity and permeability analysis to understand the effect of the deformation bands on the fluid flow characteristics of the damage zone. Significant changes in deformation band density and connectivity occur along strike of the fault, creating zones of high connectivity in damage zones. The complexity of the damage zone and the connectivity of the deformation bands can change permeability along and across faults. Changes in intensity and strike of the deformation bands occur, particularly in linkage damage zones or remnant linkage damage zones. In these areas the intensity of deformation bands often increases, but in some cases decreases. To estimate fluid flow reduction around sandstone reservoirs, we define an 'effective damage zone', as the damage zone volume around the fault core that is topologically connected. This effective damage zone can be used to predict compartments of reduced permeability in and around the fault damage zone. We calculated the width of an effective damage zone using proportion of connecting nodes in the damage networks, and the distance from the fault at which the network is not connected. The geometry of deformation bands in the damage zone (parallel to the fault strike) results in directional differences in fluid flow reduction through the networks. Fault normal flow would be reduced significantly more than fault parallel flow if the deformation bands were connected. An increase in the proportion of deformation bands to matrix, moving towards the fault, along with increases in connectivity would result in very low fault normal permeability within the effective damage zone. Changes in fault geometry, segmentation and linkage are important controlling factors

  16. Effects of matrix characteristics and interpatch distance on functional connectivity in fragmented temperate rainforests.

    PubMed

    Magrach, Ainhoa; Larrinaga, Asier R; Santamaría, Luis

    2012-04-01

    The connectivity of remnant patches of habitat may affect the persistence of species in fragmented landscapes. We evaluated the effects of the structural connectivity of forest patches (i.e., distance between patches) and matrix class (land-cover type) on the functional connectivity of 3 bird species (the White-crested Elaenia [Elaenia albiceps], the Green-backed Firecrown Hummingbird [Sephanoides sephaniodes], and the Austral Thrush [Turdus falklandii]). We measured functional connectivity as the rate at which each species crossed from one patch to another. We also evaluated whether greater functional connectivity translated into greater ecological connectivity (dispersal of fruit and pollen) by comparing among forest patches fruit set of a plant pollinated by hummingbirds and abundance of seedlings and adults of 2 plants with bird- and wind-dispersed seeds. Interpatch distance was strongly associated with functional connectivity, but its effect was not independent of matrix class. For one of the bird-dispersed plants, greater functional connectivity for White-crested Elaenias and Austral Thrushes (both frugivores) was associated with higher densities of this plant. The lack of a similar association for the wind-dispersed species suggests this effect is linked to the dispersal vector. The abundance of the hummingbird-pollinated species was not related to the presence of hummingbirds. Interpatch distance and matrix class affect animal movement in fragmented landscapes and may have a cascading effect on the distribution of some animal-dispersed species. On the basis of our results, we believe effort should be invested in optimizing patch configuration and modifying the matrix so as to mitigate the effects of patch isolation in fragmented landscapes. PMID:22443129

  17. Resource type influences the effects of reserves and connectivity on ecological functions.

    PubMed

    Yabsley, Nicholas A; Olds, Andrew D; Connolly, Rod M; Martin, Tyson S H; Gilby, Ben L; Maxwell, Paul S; Huijbers, Chantal M; Schoeman, David S; Schlacher, Thomas A

    2016-03-01

    Connectivity is a pivotal feature of landscapes that affects the structure of populations and the functioning of ecosystems. It is also a key consideration in conservation planning. But the potential functional effects of landscape connectivity are rarely evaluated in a conservation context. The removal of algae by herbivorous fish is a key ecological function on coral reefs that promotes coral growth and recruitment. Many reef herbivores are harvested and some use other habitats (like mangroves) as nurseries or feeding areas. Thus, the effects of habitat connectivity and marine reserves can jointly promote herbivore populations on coral reefs, thereby influencing reef health. We used a coral reef seascape in eastern Australia to test whether seascape connectivity and reserves influence herbivory. We measured herbivore abundance and rates of herbivory (on turf algae and macroalgae) on reefs that differed in both their level of connectivity to adjacent mangrove habitats and their level of protection from fishing. Reserves enhanced the biomass of herbivorous fish on coral reefs in all seascape settings and promoted consumption of turf algae. Consumption of turf algae was correlated with the biomass of surgeonfish that are exploited outside reserves. By contrast, both reserve status and connectivity influenced herbivory on macroalgae. Consumption of macroalgae was greatest on fished reefs that were far from mangroves and was not strongly correlated with any fish species. Our findings demonstrate that landscape connectivity and reserve status can jointly affect the functioning of ecosystems. Moreover, we show that reserve and connectivity effects can differ markedly depending on resource type (in this case turf algae vs. macroalgae). The effectiveness of conservation initiatives will therefore depend on our ability to understand how these multiple interactive effects structure the distribution of ecological functions. These findings have wider implications for the

  18. Connecting Learning & Technology for Effective Lesson Plan Design.

    ERIC Educational Resources Information Center

    Seamon, Mary P.

    This paper focuses on the design of effective lesson plans using the Internet. Effective lesson design helps students to explore ideas, acquire and synthesize information, and frame and solve problems. The creative problem solving which depends upon context, interrelationships, and real-world activities is available through Internet projects.…

  19. Effective Teaching in Higher Education: The Community College Connection

    ERIC Educational Resources Information Center

    Shepherd, Kimberly M.

    2009-01-01

    Although community colleges are seen as "teaching institutions" there is little, if any, data to support this notion. This study looked at community college instructors' conceptions of effective teaching and their reported usage of effective teaching methods. Survey method was chosen as the most efficient means of collecting an amount of data that…

  20. Reciprocal Effects of Oxidative Stress on Heme Oxygenase Expression and Activity Contributes to Reno-Vascular Abnormalities in EC-SOD Knockout Mice

    PubMed Central

    Kawakami, Tomoko; Puri, Nitin; Sodhi, Komal; Bellner, Lars; Takahashi, Toru; Morita, Kiyoshi; Rezzani, Rita; Oury, Tim D.; Abraham, Nader G.

    2012-01-01

    Heme oxygenase (HO) system is one of the key regulators of cellular redox homeostasis which responds to oxidative stress (ROS) via HO-1 induction. However, recent reports have suggested an inhibitory effect of ROS on HO activity. In light of these conflicting reports, this study was designed to evaluate effects of chronic oxidative stress on HO system and its role in contributing towards patho-physiological abnormalities observed in extracellular superoxide dismutase (EC-SOD, SOD3) KO animals. Experiments were performed in WT and EC-SOD(−/−) mice treated with and without HO inducer, cobalt protoporphyrin (CoPP). EC-SOD(−/−) mice exhibited oxidative stress, renal histopathological abnormalities, elevated blood pressure, impaired endothelial function, reduced p-eNOS, p-AKT and increased HO-1 expression; although, HO activity was significantly (P < 0.05) attenuated along with attenuation of serum adiponectin and vascular epoxide levels (P < 0.05). CoPP, in EC-SOD(−/−) mice, enhanced HO activity (P < 0.05) and reversed aforementioned pathophysiological abnormalities along with restoration of vascular EET, p-eNOS, p-AKT and serum adiponectin levels in these animals. Taken together our results implicate a causative role of insufficient activation of heme-HO-adiponectin system in pathophysiological abnormalities observed in animal models of chronic oxidative stress such as EC-SOD(−/−) mice. PMID:22292113

  1. Human effects on ecological connectivity in aquatic ecosystems: Integrating scientific approaches to support management and mitigation.

    PubMed

    Crook, David A; Lowe, Winsor H; Allendorf, Frederick W; Erős, Tibor; Finn, Debra S; Gillanders, Bronwyn M; Hadwen, Wade L; Harrod, Chris; Hermoso, Virgilio; Jennings, Simon; Kilada, Raouf W; Nagelkerken, Ivan; Hansen, Michael M; Page, Timothy J; Riginos, Cynthia; Fry, Brian; Hughes, Jane M

    2015-11-15

    Understanding the drivers and implications of anthropogenic disturbance of ecological connectivity is a key concern for the conservation of biodiversity and ecosystem processes. Here, we review human activities that affect the movements and dispersal of aquatic organisms, including damming of rivers, river regulation, habitat loss and alteration, human-assisted dispersal of organisms and climate change. Using a series of case studies, we show that the insight needed to understand the nature and implications of connectivity, and to underpin conservation and management, is best achieved via data synthesis from multiple analytical approaches. We identify four key knowledge requirements for progressing our understanding of the effects of anthropogenic impacts on ecological connectivity: autecology; population structure; movement characteristics; and environmental tolerance/phenotypic plasticity. Structuring empirical research around these four broad data requirements, and using this information to parameterise appropriate models and develop management approaches, will allow for mitigation of the effects of anthropogenic disturbance on ecological connectivity in aquatic ecosystems. PMID:25917446

  2. Network-scale effect on synchronizability of fully coupled network with connection delay.

    PubMed

    Zheng, Y G; Wang, Z H

    2016-04-01

    Network-scale effect on synchronizability of fully coupled network with connection delay is investigated in this paper. The master stability function, which governs the stability of synchronization manifold, is first obtained by separating the synchronization manifold direction from other transverse directions. Then, by introducing a new time variable in the master stability function, it is shown the effect of connection delay can be weakened with the increase of network scale, and thus, in contrast to the situation without connection delay, large network scale is more positive to the synchronizability of fully coupled network with connection delay. Those findings are confirmed by the studies on two specific networks with nodes of typical nonlinear dynamical systems. PMID:27131482

  3. Learning Effective Connectivity Network Structure from fMRI Data Based on Artificial Immune Algorithm

    PubMed Central

    Ji, Junzhong; Liu, Jinduo; Liang, Peipeng; Zhang, Aidong

    2016-01-01

    Many approaches have been designed to extract brain effective connectivity from functional magnetic resonance imaging (fMRI) data. However, few of them can effectively identify the connectivity network structure due to different defects. In this paper, a new algorithm is developed to infer the effective connectivity between different brain regions by combining artificial immune algorithm (AIA) with the Bayes net method, named as AIAEC. In the proposed algorithm, a brain effective connectivity network is mapped onto an antibody, and four immune operators are employed to perform the optimization process of antibodies, including clonal selection operator, crossover operator, mutation operator and suppression operator, and finally gets an antibody with the highest K2 score as the solution. AIAEC is then tested on Smith’s simulated datasets, and the effect of the different factors on AIAEC is evaluated, including the node number, session length, as well as the other potential confounding factors of the blood oxygen level dependent (BOLD) signal. It was revealed that, as contrast to other existing methods, AIAEC got the best performance on the majority of the datasets. It was also found that AIAEC could attain a relative better solution under the influence of many factors, although AIAEC was differently affected by the aforementioned factors. AIAEC is thus demonstrated to be an effective method for detecting the brain effective connectivity. PMID:27045295

  4. Learning Effective Connectivity Network Structure from fMRI Data Based on Artificial Immune Algorithm.

    PubMed

    Ji, Junzhong; Liu, Jinduo; Liang, Peipeng; Zhang, Aidong

    2016-01-01

    Many approaches have been designed to extract brain effective connectivity from functional magnetic resonance imaging (fMRI) data. However, few of them can effectively identify the connectivity network structure due to different defects. In this paper, a new algorithm is developed to infer the effective connectivity between different brain regions by combining artificial immune algorithm (AIA) with the Bayes net method, named as AIAEC. In the proposed algorithm, a brain effective connectivity network is mapped onto an antibody, and four immune operators are employed to perform the optimization process of antibodies, including clonal selection operator, crossover operator, mutation operator and suppression operator, and finally gets an antibody with the highest K2 score as the solution. AIAEC is then tested on Smith's simulated datasets, and the effect of the different factors on AIAEC is evaluated, including the node number, session length, as well as the other potential confounding factors of the blood oxygen level dependent (BOLD) signal. It was revealed that, as contrast to other existing methods, AIAEC got the best performance on the majority of the datasets. It was also found that AIAEC could attain a relative better solution under the influence of many factors, although AIAEC was differently affected by the aforementioned factors. AIAEC is thus demonstrated to be an effective method for detecting the brain effective connectivity. PMID:27045295

  5. Abnormal Head Position

    MedlinePlus

    ... cause. Can a longstanding head turn lead to any permanent problems? Yes, a significant abnormal head posture could cause permanent ... occipitocervical synostosis and unilateral hearing loss. Are there any ... postures? Yes. Abnormal head postures can usually be improved depending ...

  6. Urine - abnormal color

    MedlinePlus

    ... straw-yellow. Abnormally colored urine may be cloudy, dark, or blood-colored. Causes Abnormal urine color may ... red blood cells, or mucus in the urine. Dark brown but clear urine is a sign of ...

  7. Resting state connectivity in alcohol dependent patients and the effect of repetitive transcranial magnetic stimulation.

    PubMed

    Jansen, Jochem M; van Wingen, Guido; van den Brink, Wim; Goudriaan, Anna E

    2015-12-01

    Alcohol dependence is thought to result from an overactive neural motivation system and a deficient cognitive control system, and rebalancing these systems may mitigate excessive alcohol use. This study examines the differences in functional connectivity of the fronto-parietal cognitive control network (FPn) and the motivational network (striatum and orbitofrontal cortex) between alcohol dependent patients (ADPs) and healthy controls (HCs), and the effect of repetitive transcranial magnetic stimulation (rTMS) on these networks. This randomized controlled trial included 38 ADPs and 37 HCs, matched on age, gender and education. Participants were randomly assigned to sham or right dorsolateral prefrontal cortex (dlPFC) stimulation with rTMS. A 3T resting state functional Magnetic Resonance Imaging (fMRI) scan was acquired before and after active or sham 10Hz rTMS. Group differences of within and between network connectivity and the effect of rTMS on network connectivity was assessed using independent component analysis. Results showed higher connectivity within the left FPn (p=0.012) and the left fronto-striatal motivational network (p=0.03) in ADPs versus HCs, and a further increase in connectivity within the left FPn after active stimulation in ADPs. ADPs also showed higher connectivity between the left and the right FPns (p=0.025), and this higher connectivity was related to fewer alcohol related problems (r=0.30, p=0.06). The results show higher within and between network connectivity in ADPs and a further increase in fronto-parietal connectivity after right dlPFC rTMS in ADPs, suggesting that frontal rTMS may have a beneficial influence on cognitive control and may result in lower relapse rates. PMID:26481907

  8. POLLUTION EFFECTS OF ABNORMAL OPERATIONS IN IRON AND STEEL MAKING. VOLUME V. ELECTRIC ARC FURNACE, MANUAL OF PRACTICE

    EPA Science Inventory

    The report is one in a six-volume series considering abnormal operating conditions (AOCs) in the primary section (sintering, blast furnace ironmaking, open hearth, electric furnace, and basic oxygen steelmaking) of an integrated iron and steel plant. Pollution standards, generall...

  9. POLLUTION EFFECTS OF ABNORMAL OPERATIONS IN IRON AND STEEL MAKING. VOLUME IV. OPEN HEARTH FURNACE, MANUAL OF PRACTICE

    EPA Science Inventory

    The report is one in a six-volume series considering abnormal operating conditions (AOCs) in the primary section (sintering, blast furnace ironmaking, open hearth, electric furnace, and basic oxygen steelmaking) of an integrated iron and steel plant. Pollution standards, generall...

  10. POLLUTION EFFECTS OF ABNORMAL OPERATIONS IN IRON AND STEEL MAKING. VOLUME VI. BASIC OXYGEN PROCESS, MANUAL OF PRACTICE

    EPA Science Inventory

    The report is one in a six-volume series considering abnormal operating conditions (AOCs) in the primary section (sintering, blast furnace ironmaking, open hearth, electric furnace, and basic oxygen steelmaking) of an integrated iron and steel plant. Pollution standards, generall...

  11. POLLUTION EFFECTS OF ABNORMAL OPERATIONS IN IRON AND STEEL MAKING. VOLUME III. BLAST FURNACE IRONMAKING, MANUAL OF PRACTICE

    EPA Science Inventory

    The report is one in a six-volume series considering abnormal operating conditions (AOCs) in the primary section (sintering, blast furnace ironmaking, open hearth, electric furnace, and basic oxygen steelmaking) of an integrated iron and steel plant. Pollution standards, generall...

  12. Fibrillin abnormalities and prognosis in Marfan syndrome and related disorders

    SciTech Connect

    Aoyama, T.; Furthmayr, H.; Francke, U.; Gasner, C.

    1995-08-28

    Marfan syndrome (MFS), a multisystem autosomal-dominant disorder, is characterized by mutations of the fibrillin-1 (FBN1) gene and by abnormal patterns of synthesis, secretion, and matrix deposition of the fibrillin protein. To determine the sensitivity and specificity of fibrillin protein abnormalities in the diagnosis of MFS, we studied dermal fibroblasts from 57 patients with classical MFS, 15 with equivocal MFS, 8 with single-organ manifestations, and 16 with other connective tissue disorders including homocystinuria and Ehlers-Danlos syndrome. Abnormal fibrillin metabolism was identified in 70 samples that were classified into four different groups based on quantitation of fibrillin synthesis and matrix deposition. Significant correlations were found for phenotypic features including arachnodactyly, striae distensae, cardiovascular manifestations, and fibrillin groups II and IV, which included 70% of the MFS patients. In addition, these two groups were associated with shortened {open_quotes}event-free{close_quotes} survival and more severe cardiovascular complications than groups I and III. The latter included most of the equivocal MFS/single manifestation patients with fibrillin abnormalities. Our results indicate that fibrillin defects at the protein level per se are not specific for MFS, but that the drastically reduced fibrillin deposition, caused by a dominant-negative effect of abnormal fibrillin molecules in individuals defined as groups II and IV, is of prognostic and possibly diagnostic significance. 25 refs., 3 figs., 6 tabs.

  13. Extracellular Matrix Abnormalities in Schizophrenia

    PubMed Central

    Berretta, Sabina

    2011-01-01

    Emerging evidence points to the involvement of the brain extracellular matrix (ECM) in the pathophysiology of schizophrenia (SZ). Abnormalities affecting several ECM components, including Reelin and chondroitin sulfate proteoglycans (CSPGs), have been described in subjects with this disease. Solid evidence supports the involvement of Reelin, an ECM glycoprotein involved in corticogenesis, synaptic functions and glutamate NMDA receptor regulation, expressed prevalently in distinct populations of GABAergic neurons, which secrete it into the ECM. Marked changes of Reelin expression in SZ have typically been reported in association with GABA-related abnormalities in subjects with SZ and bipolar disorder. Recent findings from our group point to substantial abnormalities affecting CSPGs, a main ECM component, in the amygdala and entorhinal cortex of subjects with schizophrenia, but not bipolar disorder. Striking increases of glial cells expressing CSPGs were accompanied by reductions of perineuronal nets, CSPG- and Reelin-enriched ECM aggregates enveloping distinct neuronal populations. CSPGs developmental and adult functions, including neuronal migration, axon guidance, synaptic and neurotransmission regulation are highly relevant to the pathophysiology of SZ. Together with reports of anomalies affecting several other ECM components, these findings point to the ECM as a key component of the pathology of SZ. We propose that ECM abnormalities may contribute to several aspects of the pathophysiology of this disease, including disrupted connectivity and neuronal migration, synaptic anomalies and altered GABAergic, glutamatergic and dopaminergic neurotransmission. PMID:21856318

  14. Determination of effective brain connectivity from functional connectivity using propagator-based interferometry and neural field theory with application to the corticothalamic system

    NASA Astrophysics Data System (ADS)

    Robinson, P. A.

    2014-10-01

    It is shown how to compute both direct and total effective connection matrices (deCMs and teCMs), which embody the strengths of neural connections between regions, from correlation-based functional CMs using propagator-based interferometry, a method that stems from geophysics and acoustics, coupled with the recent identification of deCMs and teCMs with bare and dressed propagators, respectively. The approach incorporates excitatory and inhibitory connections, multiple structures and populations, and measurement effects. The propagator is found for a generalized scalar wave equation derived from neural field theory, and expressed in terms of neural activity correlations and covariances, and wave damping rates. It is then related to correlation matrices that are commonly used to express functional and effective connectivities in the brain. The results are illustrated in analytically tractable test cases.

  15. Oxytocin's effect on resting-state functional connectivity varies by age and sex.

    PubMed

    Ebner, Natalie C; Chen, Huaihou; Porges, Eric; Lin, Tian; Fischer, Håkan; Feifel, David; Cohen, Ronald A

    2016-07-01

    The neuropeptide oxytocin plays a role in social cognition and affective processing. The neural processes underlying these effects are not well understood. Modulation of connectivity strength between subcortical and cortical regions has been suggested as one possible mechanism. The current study investigated effects of intranasal oxytocin administration on resting-state functional connectivity between amygdala and medial prefrontal cortex (mPFC), as two regions involved in social-cognitive and affective processing. Going beyond previous work that largely examined young male participants, our study comprised young and older men and women to identify age and sex variations in oxytocin's central processes. This approach was based on known hormonal differences among these groups and emerging evidence of sex differences in oxytocin's effects on amygdala reactivity and age-by-sex-modulated effects of oxytocin in affective processing. In a double-blind design, 79 participants were randomly assigned to self-administer either intranasal oxytocin or placebo before undergoing resting-state functional magnetic resonance imaging. Using a targeted region-to-region approach, resting-state functional connectivity strength between bilateral amygdala and mPFC was examined. Participants in the oxytocin compared to the placebo group and men compared to women had overall greater amygdala-mPFC connectivity strength at rest. These main effects were qualified by a significant three-way interaction: while oxytocin compared to placebo administration increased resting-state amygdala-mPFC connectivity for young women, oxytocin did not significantly influence connectivity in the other age-by-sex subgroups. This study provides novel evidence of age-by-sex differences in how oxytocin modulates resting-state brain connectivity, furthering our understanding of how oxytocin affects brain networks at rest. PMID:27032063

  16. Decreased Effective Connectivity from Cortices to the Right Parahippocampal Gyrus in Alzheimer's Disease Subjects

    PubMed Central

    Chen, Guangyu; Ward, B. Douglas; Chen, Gang

    2014-01-01

    Abstract The purpose of this study was to detect effective connectivity (EC) changes in the default mode network and hippocampus network in 20 patients with Alzheimer's disease (AD) and 20 cognitively normal (CN) subjects, using multivariate Granger causality. The authors used the maximum coefficients in the multivariate autoregression model to quantitatively measure the different EC strength levels between the CN and AD groups. It was demonstrated that the EC strength difference can classify AD from CN subjects. Further, the right parahippocampal gyrus (PHP_R) showed imbalanced bidirectional EC connections. The PHP_R received weaker input connections from the neocortices, but its output connections were significantly increased in AD. These findings may provide neural physiological mechanisms for interpreting AD subjects' memory deficits during the encoding processes. PMID:25132215

  17. Normalizing effect of heroin maintenance treatment on stress-induced brain connectivity.

    PubMed

    Schmidt, André; Walter, Marc; Gerber, Hana; Seifritz, Erich; Brenneisen, Rudolf; Wiesbeck, Gerhard A; Riecher-Rössler, Anita; Lang, Undine E; Borgwardt, Stefan

    2015-01-01

    Recent evidence has shown that a single maintenance dose of heroin attenuates psychophysiological stress responses in heroin-dependent patients, probably reflecting the effectiveness of heroin-assisted therapies for the treatment of severe heroin addiction. However, the underlying neural circuitry of these effects has not yet been investigated. Using a cross-over, double-blind, vehicle-controlled design, 22 heroin-dependent and heroin-maintained outpatients from the Centre of Substance Use Disorders at the University Hospital of Psychiatry in Basel were studied after heroin and placebo administration, while 17 healthy controls from the general population were included for placebo administration only. Functional magnetic resonance imaging was used to detect brain responses to fearful faces and dynamic causal modelling was applied to compute fear-induced modulation of connectivity within the emotional face network. Stress responses were assessed by hormone releases and subjective ratings. Relative to placebo, heroin acutely reduced the fear-induced modulation of connectivity from the left fusiform gyrus to the left amygdala and from the right amygdala to the right orbitofrontal cortex in dependent patients. Both of these amygdala-related connectivity strengths were significantly increased in patients after placebo treatment (acute withdrawal) compared to healthy controls, whose connectivity estimates did not differ from those of patients after heroin injection. Moreover, we found positive correlations between the left fusiform gyrus to amygdala connectivity and different stress responses, as well as between the right amygdala to orbitofrontal cortex connectivity and levels of craving. Our findings indicate that the increased amygdala-related connectivity during fearful face processing after the placebo treatment in heroin-dependent patients transiently normalizes after acute heroin maintenance treatment. Furthermore, this study suggests that the assessment of

  18. Effects of ocean acidification driven by elevated CO2 on larval shell growth and abnormal rates of the venerid clam, Mactra veneriformis

    NASA Astrophysics Data System (ADS)

    Kim, Jee-Hoon; Yu, Ok Hwan; Yang, Eun Jin; Kang, Sung-Ho; Kim, Won; Choy, Eun Jung

    2016-03-01

    The venerid clam (Mactra veneriformis Reeve 1854) is one of the main cultured bivalve species in intertidal and shallow subtidal ecosystems along the west coast of Korea. To understand the effects of ocean acidification on the early life stages of Korean clams, we investigated shell growth and abnormality rates and types in the D-shaped, umbonate veliger, and pediveliger stages of the venerid clam M. veneriformis during exposure to elevated seawater pCO2. In particular, we examined abnormal types of larval shell morphology categorized as shell deformations, shell distortions, and shell fissures. Specimens were incubated in seawater equilibrated with bubbled CO2-enriched air at (400±25)×10-6 (ambient control), (800±25)×10-6 (high pCO2), or (1 200±28)×10-6 (extremely high pCO2), the atmospheric CO2 concentrations predicted for the years 2014, 2084, and 2154 (70-year intervals; two human generations), respectively, in the Representative Concentration Pathway (RCP) 8.5 scenario. The mean shell lengths of larvae were significantly decreased in the high and extremely high pCO2 groups compared with the ambient control groups. Furthermore, under high and extremely high pCO2 conditions, the cultures exhibited significantly increased abundances of abnormal larvae and increased severity of abnormalities compared with the ambient control. In the umbonate veliger stage of the experimental larvae, the most common abnormalities were shell deformations, distortions, and fissures; on the other hand, convex hinges and mantle protuberances were absent. These results suggest that elevated CO2 exerts an additional burden on the health of M. veneriformis larvae by impairing early development.

  19. Paramagnetic Meissner effect in multiply-connected superconductors

    NASA Astrophysics Data System (ADS)

    Nielsen, A. P.; Cawthorne, A. B.; Wellstood, F. C.; Lobb, C. J.; Barbara, P.; Forrester, M. G.; Newrock, R. S.

    2001-03-01

    We have measured a paramagnetic Meissner effect in square Nb-Al_2O_3-Nb Josephson-junction arrays of different sizes (100×150 and 100×30 junctions) using a scanning SQUID microscope. We find that although the array is sometimes diamagnetic, it is preferentially paramagnetic and increasingly paramagnetic with increasing external field, for external fields from zero Φ0 up to 20 Φ0 per unit cell of the array, where Φ0 is the flux quantum. In all cases, we observe diamagnetic screening currents around the edge of the sample. We present a simple model which describes remarkably well the observed paramagnetic phenomena, and is generally applicable to any granular superconducting sample in which the grain size is larger than the penetration depth.

  20. Spirometric abnormalities among welders

    SciTech Connect

    Rastogi, S.K.; Gupta, B.N.; Husain, T.; Mathur, N.; Srivastava, S. )

    1991-10-01

    A group of manual welders age group 13-60 years having a mean exposure period of 12.4 {plus minus} 1.12 years were subjected to spirometry to evaluate the prevalence of spirometric abnormalities. The welders showed a significantly higher prevalence of respiratory impairment than that observed among the unexposed controls as a result of exposure to welding gases which comprised fine particles of lead, zinc, chromium, and manganese. This occurred despite the lower concentration of the pollutants at the work place. In the expose group, the smoking welders showed a prevalence of respiratory impairment significantly higher than that observed in the nonsmoking welders. The results of the pulmonary function tests showed a predominantly restrictive type of pulmonary impairment followed by a mixed ventilatory defect among the welders. The effect of age on pulmonary impairment was not discernible. Welders exposed for over 10 years showed a prevalence of respiratory abnormalities significantly higher than those exposed for less than 10 years. Smoking also had a contributory role.

  1. Effects of microgravity on rat bone, cartlage and connective tissues

    NASA Technical Reports Server (NTRS)

    Doty, S.

    1990-01-01

    The response to hypogravity by the skeletal system was originally thought to be the result of a reduction in weight bearing. Thus a reduced rate of new bone formation in the weight-bearing bones was accepted, when found, as an obvious result of hypogravity. However, data on non-weight-bearing tissues have begun to show that other physiological changes can be expected to occur to animals during spaceflight. This overview of the Cosmos 1887 data discusses these results as they pertain to individual bones or tissues because the response seems to depend on the architecture and metabolism of each tissue under study. Various effects were seen in different tissues from the rats flown on Cosmos 1887. The femur showed a reduced bone mineral content but only in the central region of the diaphysis. This same region in the tibia showed changes in the vascularity of bone as well as some osteocytic cell death. The humerus demonstrated reduced morphometric characteristics plus a decrease in mechanical stiffness. Bone mineral crystals did not mature normally as a result of flight, suggesting a defect in the matrix mineralization process. Note that these changes relate directly to the matrix portion of the bone or some function of bone which slowly responds to changes in the environment. However, most cellular functions of bone are rapid responders. The stimulation of osteoblast precursor cells, the osteoblast function in collagen synthesis, a change in the proliferation rate of cells in the epiphyseal growth plate, the synthesis and secretion of osteocalcin, and the movement of water into or out of tissues, are all processes which respond to environmental change. These rapidly responding events produced results from Cosmos 1887 which were frequently quite different from previous space flight data.

  2. Extending Transfer Entropy Improves Identification of Effective Connectivity in a Spiking Cortical Network Model

    PubMed Central

    Ito, Shinya; Hansen, Michael E.; Heiland, Randy; Lumsdaine, Andrew; Litke, Alan M.; Beggs, John M.

    2011-01-01

    Transfer entropy (TE) is an information-theoretic measure which has received recent attention in neuroscience for its potential to identify effective connectivity between neurons. Calculating TE for large ensembles of spiking neurons is computationally intensive, and has caused most investigators to probe neural interactions at only a single time delay and at a message length of only a single time bin. This is problematic, as synaptic delays between cortical neurons, for example, range from one to tens of milliseconds. In addition, neurons produce bursts of spikes spanning multiple time bins. To address these issues, here we introduce a free software package that allows TE to be measured at multiple delays and message lengths. To assess performance, we applied these extensions of TE to a spiking cortical network model (Izhikevich, 2006) with known connectivity and a range of synaptic delays. For comparison, we also investigated single-delay TE, at a message length of one bin (D1TE), and cross-correlation (CC) methods. We found that D1TE could identify 36% of true connections when evaluated at a false positive rate of 1%. For extended versions of TE, this dramatically improved to 73% of true connections. In addition, the connections correctly identified by extended versions of TE accounted for 85% of the total synaptic weight in the network. Cross correlation methods generally performed more poorly than extended TE, but were useful when data length was short. A computational performance analysis demonstrated that the algorithm for extended TE, when used on currently available desktop computers, could extract effective connectivity from 1 hr recordings containing 200 neurons in ∼5 min. We conclude that extending TE to multiple delays and message lengths improves its ability to assess effective connectivity between spiking neurons. These extensions to TE soon could become practical tools for experimentalists who record hundreds of spiking neurons. PMID:22102894

  3. Extending transfer entropy improves identification of effective connectivity in a spiking cortical network model.

    PubMed

    Ito, Shinya; Hansen, Michael E; Heiland, Randy; Lumsdaine, Andrew; Litke, Alan M; Beggs, John M

    2011-01-01

    Transfer entropy (TE) is an information-theoretic measure which has received recent attention in neuroscience for its potential to identify effective connectivity between neurons. Calculating TE for large ensembles of spiking neurons is computationally intensive, and has caused most investigators to probe neural interactions at only a single time delay and at a message length of only a single time bin. This is problematic, as synaptic delays between cortical neurons, for example, range from one to tens of milliseconds. In addition, neurons produce bursts of spikes spanning multiple time bins. To address these issues, here we introduce a free software package that allows TE to be measured at multiple delays and message lengths. To assess performance, we applied these extensions of TE to a spiking cortical network model (Izhikevich, 2006) with known connectivity and a range of synaptic delays. For comparison, we also investigated single-delay TE, at a message length of one bin (D1TE), and cross-correlation (CC) methods. We found that D1TE could identify 36% of true connections when evaluated at a false positive rate of 1%. For extended versions of TE, this dramatically improved to 73% of true connections. In addition, the connections correctly identified by extended versions of TE accounted for 85% of the total synaptic weight in the network. Cross correlation methods generally performed more poorly than extended TE, but were useful when data length was short. A computational performance analysis demonstrated that the algorithm for extended TE, when used on currently available desktop computers, could extract effective connectivity from 1 hr recordings containing 200 neurons in ∼5 min. We conclude that extending TE to multiple delays and message lengths improves its ability to assess effective connectivity between spiking neurons. These extensions to TE soon could become practical tools for experimentalists who record hundreds of spiking neurons. PMID:22102894

  4. Donepezil effects on hippocampal and prefrontal functional connectivity in Alzheimer's disease: preliminary report.

    PubMed

    Zaidel, Liam; Allen, Greg; Cullum, C Munro; Briggs, Richard W; Hynan, Linda S; Weiner, Myron F; McColl, Roderick; Gopinath, Kaundinya S; McDonald, Elizabeth; Rubin, Craig D

    2012-01-01

    We used functional connectivity magnetic resonance imaging (fcMRI) to investigate changes in interhemispheric brain connectivity in 11 patients with mild Alzheimer's disease (AD) following eight weeks of treatment with the cholinesterase inhibitor donepezil. We examined functional connectivity between four homologous temporal, frontal, and occipital regions. These regions were selected to represent sites of AD neuropathology, sites of donepezil-related brain activation change in prior studies, and sites that are minimally affected by the pathologic changes of AD. Based on previous findings of selective, localized frontal responses to donepezil, we predicted that frontal connectivity would be most strongly impacted by treatment. Of the areas examined, we found that treatment had a significant effect only on functional connectivity between right and left dorsolateral prefrontal cortices. Implications for understanding the impact of donepezil treatment on brain functioning and behavior in patients with AD are discussed. This preliminary report suggests that fcMRI may provide a useful index of treatment outcome in diseases affecting brain connectivity. Future research should investigate these treatment-related changes in larger samples of patients and age-matched controls. PMID:22886013

  5. A least trimmed square regression method for second level FMRI effective connectivity analysis.

    PubMed

    Li, Xingfeng; Coyle, Damien; Maguire, Liam; McGinnity, Thomas Martin

    2013-01-01

    We present a least trimmed square (LTS) robust regression method to combine different runs/subjects for second/high level effective connectivity analysis. The basic idea of this method is to treat the extreme nonlinear model variability as outliers if they exceed a certain threshold. A bootstrap method for the LTS estimation is employed to detect model outliers. We compared the LTS robust method with a non-robust method using simulated and real datasets. The difference between LTS and the non-robust method for second level effective connectivity analysis is significant, suggesting the conventional non-robust method is easily affected by the model variability from the first level analysis. In addition, after these outliers are detected and excluded for the high level analysis, the model coefficients of the second level are combined within the framework of a mixed model. The variance of the mixed model is estimated using the Newton-Raphson (NR) type Levenberg-Marquardt algorithm. Three sets of real data are adopted to compare conventional methods which do not include random effects in the analysis with a mixed model for second level effective connectivity analysis. The results show that the conventional method is significantly different from the mixed model when greater model variability exists, suggesting there is a strong random effect, and the mixed model should be employed for the second level effective connectivity analysis. PMID:23093379

  6. The Effective Connectivity Between the Two Primary Motor Areas in the Brain during Bilateral Tapping of Hand Fingers

    NASA Astrophysics Data System (ADS)

    Yusoff, A. N.; Hamid, K. A.

    Dynamic causal modeling (DCM) was implemented on datasets obtained from an externally-triggered finger tapping functional MRI experiment performed by 5 male and female subjects. The objective was to model the effective connectivity between two significantly activated primary motor regions (M1). The left and right hemisphere M1s are found to be effectively and bidirectionally connected to each other. Both connections are modulated by the stimulus-free contextual input. These connectivities are however not gated (influenced) by any of the two M1s, ruling out the possibility of the non-linear behavior of connections between both M1s. A dynamic causal model was finally suggested.

  7. Seismic response of 3D steel buildings considering the effect of PR connections and gravity frames.

    PubMed

    Reyes-Salazar, Alfredo; Bojórquez, Edén; Haldar, Achintya; López-Barraza, Arturo; Rivera-Salas, J Luz

    2014-01-01

    The nonlinear seismic responses of 3D steel buildings with perimeter moment resisting frames (PMRF) and interior gravity frames (IGF) are studied explicitly considering the contribution of the IGF. The effect on the structural response of the stiffness of the beam-to-column connections of the IGF, which is usually neglected, is also studied. It is commonly believed that the flexibility of shear connections is negligible and that 2D models can be used to properly represent 3D real structures. The results of the study indicate, however, that the moments developed on columns of IGF can be considerable and that modeling buildings as plane frames may result in very conservative designs. The contribution of IGF to the lateral structural resistance may be significant. The contribution increases when their connections are assumed to be partially restrained (PR). The incremented participation of IGF when the stiffness of their connections is considered helps to counteract the no conservative effect that results in practice when lateral seismic loads are not considered in IGF while designing steel buildings with PMRF. Thus, if the structural system under consideration is used, the three-dimensional model should be used in seismic analysis and the IGF and the stiffness of their connections should be considered as part of the lateral resistance system. PMID:24995357

  8. Seismic Response of 3D Steel Buildings considering the Effect of PR Connections and Gravity Frames

    PubMed Central

    Haldar, Achintya; López-Barraza, Arturo; Rivera-Salas, J. Luz

    2014-01-01

    The nonlinear seismic responses of 3D steel buildings with perimeter moment resisting frames (PMRF) and interior gravity frames (IGF) are studied explicitly considering the contribution of the IGF. The effect on the structural response of the stiffness of the beam-to-column connections of the IGF, which is usually neglected, is also studied. It is commonly believed that the flexibility of shear connections is negligible and that 2D models can be used to properly represent 3D real structures. The results of the study indicate, however, that the moments developed on columns of IGF can be considerable and that modeling buildings as plane frames may result in very conservative designs. The contribution of IGF to the lateral structural resistance may be significant. The contribution increases when their connections are assumed to be partially restrained (PR). The incremented participation of IGF when the stiffness of their connections is considered helps to counteract the no conservative effect that results in practice when lateral seismic loads are not considered in IGF while designing steel buildings with PMRF. Thus, if the structural system under consideration is used, the three-dimensional model should be used in seismic analysis and the IGF and the stiffness of their connections should be considered as part of the lateral resistance system. PMID:24995357

  9. Altered effective connectivity within default mode network in major depression disorder

    NASA Astrophysics Data System (ADS)

    Li, Liang; Li, Baojuan; Bai, Yuanhan; Wang, Huaning; Zhang, Linchuan; Cui, Longbiao; Lu, Hongbing

    2016-03-01

    Understanding the neural basis of Major Depressive Disorder (MDD) is important for the diagnosis and treatment of this mental disorder. The default mode network (DMN) is considered to be highly involved in the MDD. To find directed interaction between DMN regions associated with the development of MDD, the effective connectivity within the DMN of the MDD patients and matched healthy controls was estimated by using a recently developed spectral dynamic causal modeling. Sixteen patients with MDD and sixteen matched healthy control subjects were included in this study. While the control group underwent the resting state fMRI scan just once, all patients underwent resting state fMRI scans before and after two months' treatment. The spectral dynamic causal modeling was used to estimate directed connections between four DMN nodes. Statistical analysis on connection strengths indicated that efferent connections from the medial frontal cortex (MFC) to posterior cingulate cortex (PCC) and to right parietal cortex (RPC) were significant higher in pretreatment MDD patients than those of the control group. After two-month treatment, the efferent connections from the MFC decreased significantly, while those from the left parietal cortex (LPC) to MFC, PCC and RPC showed a significant increase. These findings suggest that the MFC may play an important role for inhibitory conditioning of the DMN, which was disrupted in MDD patients. It also indicates that disrupted suppressive function of the MFC could be effectively restored after two-month treatment.

  10. Tooth - abnormal shape

    MedlinePlus

    Hutchinson incisors; Abnormal tooth shape; Peg teeth; Mulberry teeth; Conical teeth ... The appearance of normal teeth varies, especially the molars. ... conditions. Specific diseases can affect tooth shape, tooth ...

  11. Tooth - abnormal shape

    MedlinePlus

    Hutchinson incisors; Abnormal tooth shape; Peg teeth; Mulberry teeth; Conical teeth ... from many different conditions. Specific diseases can affect tooth shape, tooth color, time of appearance, or absence ...

  12. Generating Animal and Tool Names: An fMRI Study of Effective Connectivity

    ERIC Educational Resources Information Center

    Vitali, P.; Abutalebi, J.; Tettamanti, M.; Rowe, J.; Scifo, P.; Fazio, F.; Cappa, S.F.; Perani, D.

    2005-01-01

    The present fMRI study of semantic fluency for animal and tool names provides further evidence for category-specific brain activations, and reports task-related changes in effective connectivity among defined cerebral regions. Two partially segregated systems of functional integration were highlighted: the tool condition was associated with an…

  13. Brain Mapping-Based Model of Δ(9)-Tetrahydrocannabinol Effects on Connectivity in the Pain Matrix.

    PubMed

    Walter, Carmen; Oertel, Bruno G; Felden, Lisa; Kell, Christian A; Nöth, Ulrike; Vermehren, Johannes; Kaiser, Jochen; Deichmann, Ralf; Lötsch, Jörn

    2016-05-01

    Cannabinoids receive increasing interest as analgesic treatments. However, the clinical use of Δ(9)-tetrahydrocannabinol (Δ(9)-THC) has progressed with justified caution, which also owes to the incomplete mechanistic understanding of its analgesic effects, in particular its interference with the processing of sensory or affective components of pain. The present placebo-controlled crossover study therefore focused on the effects of 20 mg oral THC on the connectivity between brain areas of the pain matrix following experimental stimulation of trigeminal nocisensors in 15 non-addicted healthy volunteers. A general linear model (GLM) analysis identified reduced activations in the hippocampus and the anterior insula following THC administration. However, assessment of psychophysiological interaction (PPI) revealed that the effects of THC first consisted in a weakening of the interaction between the thalamus and the secondary somatosensory cortex (S2). From there, dynamic causal modeling (DCM) was employed to infer that THC attenuated the connections to the hippocampus and to the anterior insula, suggesting that the reduced activations in these regions are secondary to a reduction of the connectivity from somatosensory regions by THC. These findings may have consequences for the way THC effects are currently interpreted: as cannabinoids are increasingly considered in pain treatment, present results provide relevant information about how THC interferes with the affective component of pain. Specifically, the present experiment suggests that THC does not selectively affect limbic regions, but rather interferes with sensory processing which in turn reduces sensory-limbic connectivity, leading to deactivation of affective regions. PMID:26514581

  14. The Effects of Check & Connect on the School-Related Violent Behaviors of African American Females

    ERIC Educational Resources Information Center

    Seaton, Angela T.

    2010-01-01

    This study assessed the effects of a modified version of Check & Connect, a comprehensive student engagement intervention, on the attendance, behavior, and academic performance of secondary African American females with violent and aggressive behavior problems. In addition, the Student Engagement Instrument (SEI) was used to assess cognitive…

  15. Effective Brain Connectivity in Children with Reading Difficulties during Phonological Processing

    ERIC Educational Resources Information Center

    Cao, Fan; Bitan, Tali; Booth, James R.

    2008-01-01

    Using Dynamic Causal Modeling (DCM) and functional magnetic resonance imaging (fMRI), we examined effective connectivity between three left hemisphere brain regions (inferior frontal gyrus, inferior parietal lobule, fusiform gyrus) and bilateral medial frontal gyrus in 12 children with reading difficulties (M age = 12.4, range: 8.11-14.10) and 12…

  16. Effect of Cues to Increase Sound Pressure Level on Respiratory Kinematic Patterns during Connected Speech

    ERIC Educational Resources Information Center

    Huber, Jessica E.

    2007-01-01

    Purpose: This study examined the response of the respiratory system to 3 cues used to elicit increased vocal loudness to determine whether the effects of cueing, shown previously in sentence tasks, were present in connected speech tasks and to describe differences among tasks. Method: Fifteen young men and 15 young women produced a 2-paragraph…

  17. Cortical chemoarchitecture shapes macroscale effective functional connectivity patterns in macaque cerebral cortex.

    PubMed

    Turk, Elise; Scholtens, Lianne H; van den Heuvel, Martijn P

    2016-05-01

    The mammalian cortex is a complex system of-at the microscale level-interconnected neurons and-at the macroscale level-interconnected areas, forming the infrastructure for local and global neural processing and information integration. While the effects of regional chemoarchitecture on local cortical activity are well known, the effect of local neurotransmitter receptor organization on the emergence of large scale region-to-region functional interactions remains poorly understood. Here, we examined reports of effective functional connectivity-as measured by the action of strychnine administration acting on the chemical balance of cortical areas-in relation to underlying regional variation in microscale neurotransmitter receptor density levels in the macaque cortex. Linking cortical variation in microscale receptor density levels to collated information on macroscale functional connectivity of the macaque cortex, we show macroscale patterns of effective corticocortical functional interactions-and in particular, the strength of connectivity of efferent macroscale pathways-to be related to the ratio of excitatory and inhibitory neurotransmitter receptor densities of cortical areas. Our findings provide evidence for the microscale chemoarchitecture of cortical areas to have a direct stimulating influence on the emergence of macroscale functional connectivity patterns in the mammalian brain. Hum Brain Mapp 37:1856-1865, 2016. © 2016 Wiley Periodicals, Inc. PMID:26970255

  18. A Dynamic Causal Modeling Analysis of the Effective Connectivities Underlying Top-Down Letter Processing

    ERIC Educational Resources Information Center

    Liu, Jiangang; Li, Jun; Rieth, Cory A.; Huber, David E.; Tian, Jie; Lee, Kang

    2011-01-01

    The present study employed dynamic causal modeling to investigate the effective functional connectivity between regions of the neural network involved in top-down letter processing. We used an illusory letter detection paradigm in which participants detected letters while viewing pure noise images. When participants detected letters, the response…

  19. Effective connectivity of facial expression network by using Granger causality analysis

    NASA Astrophysics Data System (ADS)

    Zhang, Hui; Li, Xiaoting

    2013-10-01

    Functional magnetic resonance imaging (fMRI) is an advanced non-invasive data acquisition technique to investigate the neural activity in human brain. In addition to localize the functional brain regions that is activated by specific cognitive task, fMRI can also be utilized to measure the task-related functional interactions among the active regions of interest (ROI) in the brain. Among the variety of analysis tools proposed for modeling the connectivity of brain regions, Granger causality analysis (GCA) measure the directions of information interactions by looking for the lagged effect among the brain regions. In this study, we use fMRI and Granger Causality analysis to investigate the effective connectivity of brain network induced by viewing several kinds of expressional faces. We focus on four kinds of facial expression stimuli: fearful, angry, happy and neutral faces. Five face selective regions of interest are localized and the effective connectivity within these regions is measured for the expressional faces. Our result based on 8 subjects showed that there is significant effective connectivity from STS to amygdala, from amygdala to OFA, aFFA and pFFA, from STS to aFFA and from pFFA to aFFA. This result suggested that there is an information flow from the STS to the amygdala when perusing expressional faces. This emotional expressional information flow that is conveyed by STS and amygdala, flow back to the face selective regions in occipital-temporal lobes, which constructed a emotional face processing network.

  20. Comparison of coupled-cluster methods which include the effects of connected triple excitations

    NASA Technical Reports Server (NTRS)

    Scuseria, Gustavo E.; Lee, Timothy J.

    1990-01-01

    The 'coupled cluster single, double, and triple' (CCSDT) excitation model has been used to ascertain electron correlation energies for 14 different molecules representing a variety of chemical bonds, in conjunction with several methods of this type 'CCSDT-x', which include only an approximate treatment of connected triple excitations; these methods encompass CCSDT-1a, -1b, -2, -3, and -4, as well as the novel CCSD(T). While all methods treat the effects of connected triple excitations iteratively, CCSD(T) approaches then perturbationally. For the 14 molecules considered, the CCSD(T) method's average error relative to CCSDT is substantially lower than any of the CCSDT-x methods.

  1. Effects of Bisphenol-A and Other Endocrine Disruptors Compared With Abnormalities of Schizophrenia: An Endocrine-Disruption Theory of Schizophrenia

    PubMed Central

    Brown, James S.

    2009-01-01

    In recent years, numerous substances have been identified as so-called “endocrine disruptors” because exposure to them results in disruption of normal endocrine function with possible adverse health outcomes. The pathologic and behavioral abnormalities attributed to exposure to endocrine disruptors like bisphenol-A (BPA) have been studied in animals. Mental conditions ranging from cognitive impairment to autism have been linked to BPA exposure by more than one investigation. Concurrent with these developments in BPA research, schizophrenia research has continued to find evidence of possible endocrine or neuroendocrine involvement in the disease. Sufficient information now exists for a comparison of the neurotoxicological and behavioral pathology associated with exposure to BPA and other endocrine disruptors to the abnormalities observed in schizophrenia. This review summarizes these findings and proposes a theory of endocrine disruption, like that observed from BPA exposure, as a pathway of schizophrenia pathogenesis. The review shows similarities exist between the effects of exposure to BPA and other related chemicals with schizophrenia. These similarities can be observed in 11 broad categories of abnormality: physical development, brain anatomy, cellular anatomy, hormone function, neurotransmitters and receptors, proteins and factors, processes and substances, immunology, sexual development, social behaviors or physiological responses, and other behaviors. Some of these similarities are sexually dimorphic and support theories that sexual dimorphisms may be important to schizophrenia pathogenesis. Research recommendations for further elaboration of the theory are proposed. PMID:18245062

  2. Simulation of the effect of learning on the topology of the functional connectivity of neural networks

    NASA Astrophysics Data System (ADS)

    García, I.; Jiménez, J.; Mujica, R.

    2014-04-01

    We introduce a procedure for simulating adaptive learning in neural networks and the effect this learning has on the way in which the functional connections between the nodes of the network are established. The procedure combines two mechanisms: firstly, the gradual dilution of the network through the elimination of synaptic weights in increasing order of magnitude, thus reducing the costs of the network structure. Secondly, to train the network as it is diluted so as not to compromise its performance pursuant to the proposed task. Considering different levels of learning difficulty, we compare the topology of the functional connectivities that result from the application of this procedure with those obtained using fMRI in healthy volunteers. According to our results, the topology of functional connectivities in healthy subjects can be interpreted as the product of a learning process with a specific degree of difficulty.

  3. Multimodal effective connectivity analysis reveals seizure focus and propagation in musicogenic epilepsy.

    PubMed

    Klamer, Silke; Rona, Sabine; Elshahabi, Adham; Lerche, Holger; Braun, Christoph; Honegger, Jürgen; Erb, Michael; Focke, Niels K

    2015-06-01

    Dynamic causal modeling (DCM) is a method to non-invasively assess effective connectivity between brain regions. 'Musicogenic epilepsy' is a rare reflex epilepsy syndrome in which seizures can be elicited by musical stimuli and thus represents a unique possibility to investigate complex human brain networks and test connectivity analysis tools. We investigated effective connectivity in a case of musicogenic epilepsy using DCM for fMRI, high-density (hd-) EEG and MEG and validated results with intracranial EEG recordings. A patient with musicogenic seizures was examined using hd-EEG/fMRI and simultaneous '256-channel hd-EEG'/'whole head MEG' to characterize the epileptogenic focus and propagation effects using source analysis techniques and DCM. Results were validated with invasive EEG recordings. We recorded one seizure with hd-EEG/fMRI and four auras with hd-EEG/MEG. During the seizures, increases of activity could be observed in the right mesial temporal region as well as bilateral mesial frontal regions. Effective connectivity analysis of fMRI and hd-EEG/MEG indicated that right mesial temporal neuronal activity drives changes in the frontal areas consistently in all three modalities, which was confirmed by the results of invasive EEG recordings. Seizures thus seem to originate in the right mesial temporal lobe and propagate to mesial frontal regions. Using DCM for fMRI, hd-EEG and MEG we were able to correctly localize focus and propagation of epileptic activity and thereby characterize the underlying epileptic network in a patient with musicogenic epilepsy. The concordance between all three functional modalities validated by invasive monitoring is noteworthy, both for epileptic activity spread as well as for effective connectivity analysis in general. PMID:25797835

  4. The Effects of Taekwondo Training on Brain Connectivity and Body Intelligence

    PubMed Central

    Kim, Young Jae; Cha, Eun Joo; Kim, Sun Mi; Kang, Kyung Doo

    2015-01-01

    Objective Many studies have reported that Taekwondo training could improve body perception, control and brain activity, as assessed with an electroencephalogram. This study aimed to assess body intelligence and brain connectivity in children with Taekwondo training as compared to children without Taekwondo training. Methods Fifteen children with Taekwondo training (TKD) and 13 age- and sex-matched children who had no previous experience of Taekwondo training (controls) were recruited. Body intelligence, clinical characteristics and brain connectivity in all children were assessed with the Body Intelligence Scale (BIS), self-report, and resting state functional magnetic resonance imaging. Results The mean BIS score in the TKD group was higher than that in the control group. The TKD group showed increased low-frequency fluctuations in the right frontal precentral gyrus and the right parietal precuneus, compared to the control group. The TKD group showed positive cerebellum vermis (lobe VII) seed to the right frontal, left frontal, and left parietal lobe. The control group showed positive cerebellum seed to the left frontal, parietal, and occipital cortex. Relative to the control group, the TKD group showed increased functional connectivity from cerebellum seed to the right inferior frontal gyrus. Conclusion To the best of our knowledge, this is the first study to assess the effect of Taekwondo training on brain connectivity in children. Taekwondo training improved body intelligence and brain connectivity from the cerebellum to the parietal and frontal cortex. PMID:26207126

  5. Differential effects of hunger and satiety on insular cortex and hypothalamic functional connectivity.

    PubMed

    Wright, Hazel; Li, Xiaoyun; Fallon, Nicholas B; Crookall, Rebecca; Giesbrecht, Timo; Thomas, Anna; Halford, Jason C G; Harrold, Joanne; Stancak, Andrej

    2016-05-01

    The insula cortex and hypothalamus are implicated in eating behaviour, and contain receptor sites for peptides and hormones controlling energy balance. The insula encompasses multi-functional subregions, which display differential anatomical and functional connectivities with the rest of the brain. This study aimed to analyse the effect of fasting and satiation on the functional connectivity profiles of left and right anterior, middle, and posterior insula, and left and right hypothalamus. It was hypothesized that the profiles would be altered alongside changes in homeostatic energy balance. Nineteen healthy participants underwent two 7-min resting state functional magnetic resonance imaging scans, one when fasted and one when satiated. Functional connectivity between the left posterior insula and cerebellum/superior frontal gyrus, and between left hypothalamus and inferior frontal gyrus was stronger during fasting. Functional connectivity between the right middle insula and default mode structures (left and right posterior parietal cortex, cingulate cortex), and between right hypothalamus and superior parietal cortex was stronger during satiation. Differences in blood glucose levels between the scans accounted for several of the altered functional connectivities. The insula and hypothalamus appear to form a homeostatic energy balance network related to cognitive control of eating; prompting eating and preventing overeating when energy is depleted, and ending feeding or transferring attention away from food upon satiation. This study provides evidence of a lateralized dissociation of neural responses to energy modulations. PMID:26790868

  6. Molecular abnormalities in Ewing's sarcoma.

    PubMed

    Burchill, Susan Ann

    2008-10-01

    Ewing's sarcoma is one of the few solid tumors for which the underlying molecular genetic abnormality has been described: rearrangement of the EWS gene on chromosome 22q12 with an ETS gene family member. These translocations define the Ewing's sarcoma family of tumors (ESFT) and provide a valuable tool for their accurate and unequivocal diagnosis. They also represent ideal targets for the development of tumor-specific therapeutics. Although secondary abnormalities occur in over 80% of primary ESFT the clinical utility of these is currently unclear. However, abnormalities in genes that regulate the G(1)/S checkpoint are frequently described and may be important in predicting outcome and response. Increased understanding of the molecular events that arise in ESFT and their role in the development and maintenance of the malignant phenotype will inform the improved stratification of patients for therapy and identify targets and pathways for the design of more effective cancer therapeutics. PMID:18925858

  7. Climate effects on the distribution of wetland habitats and connectivity in networks of migratory waterbirds

    NASA Astrophysics Data System (ADS)

    Bellisario, Bruno; Cerfolli, Fulvio; Nascetti, Giuseppe

    2014-07-01

    The establishment and maintenance of conservation areas are among the most common measures to mitigate the loss of biodiversity. However, recent advances in conservation biology have challenged the reliability of such areas to cope with variation in climate conditions. Climate change can reshuffle the geographic distribution of species, but in many cases suitable habitats become scarce or unavailable, limiting the ability to migrate or adapt in response to modified environments. In this respect, the extent to which existing protected areas are able to compensate changes in habitat conditions to ensure the persistence of species still remains unclear. We used a spatially explicit model to measure the effects of climate change on the potential distribution of wetland habitats and connectivity of Natura 2000 sites in Italy. The effects of climate change were measured on the potential for water accumulation in a given site, as a surrogate measure for the persistence of aquatic ecosystems and their associated migratory waterbirds. Climate impacts followed a geographic trend, changing the distribution of suitable habitats for migrants and highlighting a latitudinal threshold beyond which the connectivity reaches a sudden collapse. Our findings show the relative poor reliability of most sites in dealing with changing habitat conditions and ensure the long-term connectivity, with possible consequences for the persistence of species. Although alterations of climate suitability and habitat destruction could impact critical areas for migratory waterbirds, more research is needed to evaluate all possible long-term effects on the connectivity of migratory networks.

  8. Structurally abnormal human autosomes

    SciTech Connect

    1993-12-31

    Chapter 25, discusses structurally abnormal human autosomes. This discussion includes: structurally abnormal chromosomes, chromosomal polymorphisms, pericentric inversions, paracentric inversions, deletions or partial monosomies, cri du chat (cat cry) syndrome, ring chromosomes, insertions, duplication or pure partial trisomy and mosaicism. 71 refs., 8 figs.

  9. Common Effects of Amnestic Mild Cognitive Impairment on Resting-State Connectivity Across Four Independent Studies

    PubMed Central

    Tam, Angela; Dansereau, Christian; Badhwar, AmanPreet; Orban, Pierre; Belleville, Sylvie; Chertkow, Howard; Dagher, Alain; Hanganu, Alexandru; Monchi, Oury; Rosa-Neto, Pedro; Shmuel, Amir; Wang, Seqian; Breitner, John; Bellec, Pierre

    2015-01-01

    Resting-state functional connectivity is a promising biomarker for Alzheimer's disease. However, previous resting-state functional magnetic resonance imaging studies in Alzheimer's disease and amnestic mild cognitive impairment (aMCI) have shown limited reproducibility as they have had small sample sizes and substantial variation in study protocol. We sought to identify functional brain networks and connections that could consistently discriminate normal aging from aMCI despite variations in scanner manufacturer, imaging protocol, and diagnostic procedure. We therefore combined four datasets collected independently, including 112 healthy controls and 143 patients with aMCI. We systematically tested multiple brain connections for associations with aMCI using a weighted average routinely used in meta-analyses. The largest effects involved the superior medial frontal cortex (including the anterior cingulate), dorsomedial prefrontal cortex, striatum, and middle temporal lobe. Compared with controls, patients with aMCI exhibited significantly decreased connectivity between default mode network nodes and between regions of the cortico-striatal-thalamic loop. Despite the heterogeneity of methods among the four datasets, we identified common aMCI-related connectivity changes with small to medium effect sizes and sample size estimates recommending a minimum of 140 to upwards of 600 total subjects to achieve adequate statistical power in the context of a multisite study with 5–10 scanning sites and about 10 subjects per group and per site. If our findings can be replicated and associated with other established biomarkers of Alzheimer's disease (e.g., amyloid and tau quantification), then these functional connections may be promising candidate biomarkers for Alzheimer's disease. PMID:26733866

  10. Largely Typical Patterns of Resting-State Functional Connectivity in High-Functioning Adults with Autism

    PubMed Central

    Tyszka, J. Michael; Kennedy, Daniel P.; Paul, Lynn K.; Adolphs, Ralph

    2014-01-01

    A leading hypothesis for the neural basis of autism postulates globally abnormal brain connectivity, yet the majority of studies report effects that are either very weak, inconsistent across studies, or explain results incompletely. Here we apply multiple analytical approaches to resting-state BOLD-fMRI data at the whole-brain level. Neurotypical and high-functioning adults with autism displayed very similar patterns and strengths of resting-state connectivity. We found only limited evidence in autism for abnormal resting-state connectivity at the regional level and no evidence for altered connectivity at the whole-brain level. Regional abnormalities in functional connectivity in autism spectrum disorder were primarily in the frontal and temporal cortices. Within these regions, functional connectivity with other brain regions was almost exclusively lower in the autism group. Further examination showed that even small amounts of head motion during scanning have large effects on functional connectivity measures and must be controlled carefully. Consequently, we suggest caution in the interpretation of apparent positive findings until all possible confounding effects can be ruled out. Additionally, we do not rule out the possibility that abnormal connectivity in autism is evident at the microstructural synaptic level, which may not be reflected sensitively in hemodynamic changes measured with BOLD-fMRI. PMID:23425893

  11. Microbiota modulate behavioral and physiological abnormalities associated with neurodevelopmental disorders.

    PubMed

    Hsiao, Elaine Y; McBride, Sara W; Hsien, Sophia; Sharon, Gil; Hyde, Embriette R; McCue, Tyler; Codelli, Julian A; Chow, Janet; Reisman, Sarah E; Petrosino, Joseph F; Patterson, Paul H; Mazmanian, Sarkis K

    2013-12-19

    Neurodevelopmental disorders, including autism spectrum disorder (ASD), are defined by core behavioral impairments; however, subsets of individuals display a spectrum of gastrointestinal (GI) abnormalities. We demonstrate GI barrier defects and microbiota alterations in the maternal immune activation (MIA) mouse model that is known to display features of ASD. Oral treatment of MIA offspring with the human commensal Bacteroides fragilis corrects gut permeability, alters microbial composition, and ameliorates defects in communicative, stereotypic, anxiety-like and sensorimotor behaviors. MIA offspring display an altered serum metabolomic profile, and B. fragilis modulates levels of several metabolites. Treating naive mice with a metabolite that is increased by MIA and restored by B. fragilis causes certain behavioral abnormalities, suggesting that gut bacterial effects on the host metabolome impact behavior. Taken together, these findings support a gut-microbiome-brain connection in a mouse model of ASD and identify a potential probiotic therapy for GI and particular behavioral symptoms in human neurodevelopmental disorders. PMID:24315484

  12. Effects of hydrologic connectivity on aquatic macroinvertebrate assemblages in different marsh types

    USGS Publications Warehouse

    Kang, Sung-Ryong; King, Sammy L.

    2013-01-01

    Hydrologic connectivity can be an important driver of aquatic macroinvertebrate assemblages. Its effects on aquatic macroinvertebrate assemblages in coastal marshes, however, are relatively poorly studied. We evaluated the effects of lateral hydrologic connectivity (permanently connected ponds: PCPs; temporary connected ponds: TCPs), and other environmental variables on aquatic macroinvertebrate assemblages and functional feeding groups (FFGs) in freshwater, brackish, and saline marshes in Louisiana, USA. We hypothesized that (1) aquatic macroinvertebrate assemblages in PCPs would have higher assemblage metric values (density, biomass, Shannon-Wiener diversity) than TCPs and (2) the density and proportional abundance of certain FFGs (i.e. scrapers, shredders, and collectors) would be greater in freshwater marsh than brackish and saline marshes. The data in our study only partially supported our first hypothesis: while freshwater marsh PCPs had higher density and biomass than TCPs, assemblage metric values in saline TCPs were greater than saline PCPs. In freshwater TCPs, long duration of isolation limited access of macroinvertebrates from adjacent water bodies, which may have reduced assemblage metric values. However, the relatively short duration of isolation in saline TCPs provided more stable or similar habitat conditions, facilitating higher assemblage metric values. As predicted by our second hypothesis, freshwater PCPs and TCPs supported a greater density of scrapers, shredders, and collectors than brackish and saline ponds. Aquatic macroinvertebrate assemblages seem to be structured by individual taxa responses to salinity as well as pond habitat attributes.

  13. Resting functional connectivity in social anxiety disorder and the effect of pharmacotherapy.

    PubMed

    Doruyter, Alexander; Lochner, Christine; Jordaan, Gerhard P; Stein, Dan J; Dupont, Patrick; Warwick, James M

    2016-05-30

    Neuroimaging research has reported differences in resting-state functional connectivity (RFC) between social anxiety disorder (SAD) patients and healthy controls (HCs). Limited research has examined the effect of treatment on RFC in SAD. We performed a study to identify differences in RFC between SAD and HC groups, and to investigate the effect of pharmacotherapy on RFC in SAD. Seed-based RFC analysis was performed on technetium-99m hexamethylpropylene amine oxime (Tc-99m HMPAO) SPECT scans using a cross-subject approach in SPM-12. Seeds were chosen to represent regions in a recently published network model of SAD. A second-level regression analysis was performed to further characterize the underlying relationships identified in the group contrasts. Twenty-three SAD participants were included, of which 18 underwent follow-up measures after an 8-week course of citalopram or moclobemide. Fifteen healthy control (HC) scans were included. SAD participants at baseline demonstrated several significant connectivity disturbances consistent with the existing network model as well as one previously unreported finding (increased connectivity between cerebellum and posterior cingulate cortex). After therapy, the SAD group demonstrated significant increases in connectivity with dorsal anterior cingulate cortex which may explain therapy-induced modifications in how SAD sufferers interpret emotions in others and improvements in self-related and emotional processing. PMID:27111811

  14. Effective connectivity associated with auditory error detection in musicians with absolute pitch

    PubMed Central

    Parkinson, Amy L.; Behroozmand, Roozbeh; Ibrahim, Nadine; Korzyukov, Oleg; Larson, Charles R.; Robin, Donald A.

    2014-01-01

    It is advantageous to study a wide range of vocal abilities in order to fully understand how vocal control measures vary across the full spectrum. Individuals with absolute pitch (AP) are able to assign a verbal label to musical notes and have enhanced abilities in pitch identification without reliance on an external referent. In this study we used dynamic causal modeling (DCM) to model effective connectivity of ERP responses to pitch perturbation in voice auditory feedback in musicians with relative pitch (RP), AP, and non-musician controls. We identified a network compromising left and right hemisphere superior temporal gyrus (STG), primary motor cortex (M1), and premotor cortex (PM). We specified nine models and compared two main factors examining various combinations of STG involvement in feedback pitch error detection/correction process. Our results suggest that modulation of left to right STG connections are important in the identification of self-voice error and sensory motor integration in AP musicians. We also identify reduced connectivity of left hemisphere PM to STG connections in AP and RP groups during the error detection and corrections process relative to non-musicians. We suggest that this suppression may allow for enhanced connectivity relating to pitch identification in the right hemisphere in those with more precise pitch matching abilities. Musicians with enhanced pitch identification abilities likely have an improved auditory error detection and correction system involving connectivity of STG regions. Our findings here also suggest that individuals with AP are more adept at using feedback related to pitch from the right hemisphere. PMID:24634644

  15. Connecting Teratogen-Induced Congenital Heart Defects to Neural Crest Cells and Their Effect on Cardiac Function

    PubMed Central

    Karunamuni, Ganga H.; Ma, Pei; Gu, Shi; Rollins, Andrew M.; Jenkins, Michael W.; Watanabe, Michiko

    2014-01-01

    Neural crest cells play many key roles in embryonic development, as demonstrated by the abnormalities that result from their specific absence or dysfunction. Unfortunately, these key cells are particularly sensitive to abnormalities in various intrinsic and extrinsic factors, such as genetic deletions or ethanol-exposure that lead to morbidity and mortality for organisms. This review discusses the role identified for a segment of neural crest is in regulating the morphogenesis of the heart and associated great vessels. The paradox is that their derivatives constitute a small proportion of cells to the cardiovascular system. Findings supporting that these cells impact early cardiac function raises the interesting possibility that they indirectly control cardiovascular development at least partially through regulating function. Making connections between insults to the neural crest, cardiac function, and morphogenesis is more approachable with technological advances. Expanding our understanding of early functional consequences could be useful in improving diagnosis and testing therapies. PMID:25220155

  16. Current induced abnormal electroresistance effect observed in epitaxial La0.9Hf0.1MnO3 thin films

    NASA Astrophysics Data System (ADS)

    Xing, Jie; Gao, Ju; Wang, Le

    2014-05-01

    La0.9Hf0.1MnO3 thin films with thickness 100 nm were prepared by using a pulsed laser deposition technique. Transport behaviors were investigated under various applied currents without an applied magnetic field. When the applied current is not too large, the peak value of the resistance gradually decreases with increasing current, demonstrating a normal electroresistance (ER) effect. However, when the current reaches a critical value, a high-resistance state appears at a lower temperature below the Curie temperature. And the appeared resistance peak at low temperature turns out to be extremely sensitive to a weak current. Even a very small current could greatly depress the height of the peak, an abnormal ER effect appears. Maximum resistance ratio ER, defined as [R(1 μA)-R(100 μA)]/R(100 μA), is about 1257% at 50 K. Physics related to the appearance of the novel state and the abnormal ER effect is discussed.

  17. Time-varying effective connectivity during visual object naming as a function of semantic demands.

    PubMed

    Poch, Claudia; Garrido, Marta I; Igoa, José Manuel; Belinchón, Mercedes; García-Morales, Irene; Campo, Pablo

    2015-06-10

    Accumulating evidence suggests that visual object understanding involves a rapid feedforward sweep, after which subsequent recurrent interactions are necessary. The extent to which recurrence plays a critical role in object processing remains to be determined. Recent studies have demonstrated that recurrent processing is modulated by increasing semantic demands. Differentially from previous studies, we used dynamic causal modeling to model neural activity recorded with magnetoencephalography while 14 healthy humans named two sets of visual objects that differed in the degree of semantic accessing demands, operationalized in terms of the values of basic psycholinguistic variables associated with the presented objects (age of acquisition, frequency, and familiarity). This approach allowed us to estimate the directionality of the causal interactions among brain regions and their associated connectivity strengths. Furthermore, to understand the dynamic nature of connectivity (i.e., the chronnectome; Calhoun et al., 2014) we explored the time-dependent changes of effective connectivity during a period (200-400 ms) where adding semantic-feature information improves modeling and classifying visual objects, at 50 ms increments. First, we observed a graded involvement of backward connections, that became active beyond 200 ms. Second, we found that semantic demands caused a suppressive effect in the backward connection from inferior frontal cortex (IFC) to occipitotemporal cortex over time. These results complement those from previous studies underscoring the role of IFC as a common source of top-down modulation, which drives recurrent interactions with more posterior regions during visual object recognition. Crucially, our study revealed the inhibitory modulation of this interaction in situations that place greater demands on the conceptual system. PMID:26063911

  18. Taste intensity modulates effective connectivity from the insular cortex to the thalamus in humans.

    PubMed

    Yeung, Andy Wai Kan; Tanabe, Hiroki C; Suen, Justin Long Kiu; Goto, Tazuko K

    2016-07-15

    Evaluation of taste intensity is one of the most important perceptual abilities in our daily life. In contrast with extensive research findings regarding the spatial representation of taste in the insula and thalamus, little is known about how the thalamus and insula communicate and reciprocally influence their activities for processing taste intensity. To examine this neurophysiological relationship, we investigated the modulatory effect of intensity of saltiness on connections in the network processing taste signals in the human brain. These "effective connectivity" relationships refer to the neurophysiological influence (including direction and strength of influence) of one brain region on another. Healthy adults (N=34), including 17 males and 17 females (mean age=21.3years, SD=2.4; mean body mass index (BMI)=20.2kg/m(2), SD=2.1) underwent functional magnetic resonance imaging as they tasted three concentrations of sodium chloride solutions. By effective connectivity analysis with dynamic causal modeling, we show that taste intensity enhances top-down signal transmission from the insular cortex to the thalamus. These results are the first to demonstrate the modulatory effect of taste intensity on the taste network in the human brain. PMID:27132544

  19. Single-dose serotonergic stimulation shows widespread effects on functional brain connectivity.

    PubMed

    Klaassens, Bernadet L; van Gorsel, Helene C; Khalili-Mahani, Najmeh; van der Grond, Jeroen; Wyman, Bradley T; Whitcher, Brandon; Rombouts, Serge A R B; van Gerven, Joop M A

    2015-11-15

    The serotonergic system is widely distributed throughout the central nervous system. It is well known as a mood regulating system, although it also contributes to many other functions. With resting state functional magnetic resonance imaging (RS-fMRI) it is possible to investigate whole brain functional connectivity. We used this non-invasive neuroimaging technique to measure acute pharmacological effects of the selective serotonin reuptake inhibitor sertraline (75 mg) in 12 healthy volunteers. In this randomized, double blind, placebo-controlled, crossover study, RS-fMRI scans were repeatedly acquired during both visits (at baseline and 3, 5, 7 and 9h after administering sertraline or placebo). Within-group comparisons of voxelwise functional connectivity with ten functional networks were examined (p<0.005, corrected) using a mixed effects model with cerebrospinal fluid, white matter, motion parameters, heart rate and respiration as covariates. Sertraline induced widespread effects on functional connectivity with multiple networks; the default mode network, the executive control network, visual networks, the sensorimotor network and the auditory network. A common factor among these networks was the involvement of the precuneus and posterior cingulate cortex. Cognitive and subjective measures were taken as well, but yielded no significant treatment effects, emphasizing the sensitivity of RS-fMRI to pharmacological challenges. The results are consistent with the existence of an extensive serotonergic system relating to multiple brain functions with a possible key role for the precuneus and cingulate. PMID:26277774

  20. Brain effective connectivity during motor-imagery and execution following stroke and rehabilitation

    PubMed Central

    Bajaj, Sahil; Butler, Andrew J.; Drake, Daniel; Dhamala, Mukesh

    2015-01-01

    Brain areas within the motor system interact directly or indirectly during motor-imagery and motor-execution tasks. These interactions and their functionality can change following stroke and recovery. How brain network interactions reorganize and recover their functionality during recovery and treatment following stroke are not well understood. To contribute to answering these questions, we recorded blood oxygenation-level dependent (BOLD) functional magnetic resonance imaging (fMRI) signals from 10 stroke survivors and evaluated dynamical causal modeling (DCM)-based effective connectivity among three motor areas: primary motor cortex (M1), pre-motor cortex (PMC) and supplementary motor area (SMA), during motor-imagery and motor-execution tasks. We compared the connectivity between affected and unaffected hemispheres before and after mental practice and combined mental practice and physical therapy as treatments. The treatment (intervention) period varied in length between 14 to 51 days but all patients received the same dose of 60 h of treatment. Using Bayesian model selection (BMS) approach in the DCM approach, we found that, after intervention, the same network dominated during motor-imagery and motor-execution tasks but modulatory parameters suggested a suppressive influence of SM A on M1 during the motor-imagery task whereas the influence of SM A on M1 was unrestricted during the motor-execution task. We found that the intervention caused a reorganization of the network during both tasks for unaffected as well as for the affected hemisphere. Using Bayesian model averaging (BMA) approach, we found that the intervention improved the regional connectivity among the motor areas during both the tasks. The connectivity between PMC and M1 was stronger in motor-imagery tasks whereas the connectivity from PMC to M1, SM A to M1 dominated in motor-execution tasks. There was significant behavioral improvement (p = 0.001) in sensation and motor movements because of the

  1. Signal Propagation in the Human Visual Pathways: An Effective Connectivity Analysis.

    PubMed

    Youssofzadeh, Vahab; Prasad, Girijesh; Fagan, Andrew J; Reilly, Richard B; Martens, Sven; Meaney, James F; Wong-Lin, KongFatt

    2015-09-30

    Although the visual system has been extensively investigated, an integrated account of the spatiotemporal dynamics of long-range signal propagation along the human visual pathways is not completely known or validated. In this work, we used dynamic causal modeling approach to provide insights into the underlying neural circuit dynamics of pattern reversal visual-evoked potentials extracted from concurrent EEG-fMRI data. A recurrent forward-backward connectivity model, consisting of multiple interacting brain regions identified by EEG source localization aided by fMRI spatial priors, best accounted for the data dynamics. Sources were first identified in the thalamic area, primary visual cortex, as well as higher cortical areas along the ventral and dorsal visual processing streams. Consistent with hierarchical early visual processing, the model disclosed and quantified the neural temporal dynamics across the identified activity sources. This signal propagation is dominated by a feedforward process, but we also found weaker effective feedback connectivity. Using effective connectivity analysis, the optimal dynamic causal modeling revealed enhanced connectivity along the dorsal pathway but slightly suppressed connectivity along the ventral pathway. A bias was also found in favor of the right hemisphere consistent with functional attentional asymmetry. This study validates, for the first time, the long-range signal propagation timing in the human visual pathways. A similar modeling approach can potentially be used to understand other cognitive processes and dysfunctions in signal propagation in neurological and neuropsychiatric disorders. Significance statement: An integrated account of long-range visual signal propagation in the human brain is currently incomplete. Using computational neural modeling on our acquired concurrent EEG-fMRI data under a visual evoked task, we found not only a substantial forward propagation toward "higher-order" brain regions but also a

  2. Changes in Effective Connectivity Between Dorsal and Ventral Prefrontal Regions Moderate Emotion Regulation.

    PubMed

    Morawetz, Carmen; Bode, Stefan; Baudewig, Juergen; Kirilina, Evgeniya; Heekeren, Hauke R

    2016-05-01

    Reappraisal, the cognitive reevaluation of a potentially emotionally arousing event, has been proposed to be based upon top-down appraisal systems within the prefrontal cortex (PFC). It still remains unclear, however, how different prefrontal regions interact to control and regulate emotional responses. We used fMRI and dynamic causal modeling (DCM) to characterize the functional interrelationships among dorsal and ventral PFC regions involved in reappraisal. Specifically, we examined the effective connectivity between the inferior frontal gyrus (IFG), dorsolateral PFC (DLPFC), and other reappraisal-related regions (supplementary motor area, supramarginal gyrus) during the up- and downregulation of emotions in response to highly arousing extreme sports film clips. We found DLPFC to be the central node of the prefrontal emotion regulation network, strongly interconnected with the IFG. The DCM analysis further revealed excitatory changes of connection strength from the DLPFC to the IFG and strong inhibitory changes of connection strength between the IFG and DLPFC during reappraisal. These bidirectional changes in connectivity strength indicate a feedback mechanism by which the IFG may select one out of several possible goal-appropriate reappraisals held active in working memory (represented in the DLPFC) and inhibits the DLPFC once the selection process is completed. PMID:25631055

  3. The Direct Effect of Flexible Walls on Fontan Connection Fluid Dynamics

    NASA Astrophysics Data System (ADS)

    Tree, Mike; Fagan, Kiley; Yoganathan, Ajit

    2014-11-01

    The current standard treatment for sufferers of congenital heart defects is the palliative Fontan procedure. The Fontan procedure results in an anastomosis of major veins directly to the branched pulmonary arteries bypassing the dysfunctional ventricle. This total cavopulmonary connection (TCPC) extends life past birth, but Fontan patients still suffer long-term complications like decreased exercise capacity, protein-losing enteropathy, and pulmonary arteriovenous malformations (PAVM). These complications have direct ties to fluid dynamics within the connection. Previous experimental and computation studies of Fontan connection fluid dynamics employed rigid vessel models. More recent studies utilize flexible models, but a direct comparison of the fundamental fluid dynamics between rigid and flexible vessels only exists for a computational model, without a direct experimental validation. Thus, this study was a direct comparison of fluid dynamics within a rigid and two compliant idealized TCPCs. 2D particle image velocimetry measurements were collected at the connection center plane. Results include power loss, hepatic flow distribution, fluid shear stress, and flow structure recognition. The effect of flexible walls on these values and clinical impact will be discussed.

  4. Structural and effective connectivity reveals potential network-based influences on category-sensitive visual areas

    PubMed Central

    Furl, Nicholas

    2015-01-01

    Visual category perception is thought to depend on brain areas that respond specifically when certain categories are viewed. These category-sensitive areas are often assumed to be “modules” (with some degree of processing autonomy) and to act predominantly on feedforward visual input. This modular view can be complemented by a view that treats brain areas as elements within more complex networks and as influenced by network properties. This network-oriented viewpoint is emerging from studies using either diffusion tensor imaging to map structural connections or effective connectivity analyses to measure how their functional responses influence each other. This literature motivates several hypotheses that predict category-sensitive activity based on network properties. Large, long-range fiber bundles such as inferior fronto-occipital, arcuate and inferior longitudinal fasciculi are associated with behavioral recognition and could play crucial roles in conveying backward influences on visual cortex from anterior temporal and frontal areas. Such backward influences could support top-down functions such as visual search and emotion-based visual modulation. Within visual cortex itself, areas sensitive to different categories appear well-connected (e.g., face areas connect to object- and motion sensitive areas) and their responses can be predicted by backward modulation. Evidence supporting these propositions remains incomplete and underscores the need for better integration of DTI and functional imaging. PMID:25999841

  5. Electroencephalographic effects of ketamine on power, cross-frequency coupling, and connectivity in the alpha bandwidth

    PubMed Central

    Blain-Moraes, Stefanie; Lee, UnCheol; Ku, SeungWoo; Noh, GyuJeong; Mashour, George A.

    2014-01-01

    Recent studies of propofol-induced unconsciousness have identified characteristic properties of electroencephalographic alpha rhythms that may be mediated by drug activity at γ-aminobutyric acid (GABA) receptors in the thalamus. However, the effect of ketamine (a primarily non-GABAergic anesthetic drug) on alpha oscillations has not been systematically evaluated. We analyzed the electroencephalogram of 28 surgical patients during consciousness and ketamine-induced unconsciousness with a focus on frontal power, frontal cross-frequency coupling, frontal-parietal functional connectivity (measured by coherence and phase lag index), and frontal-to-parietal directional connectivity (measured by directed phase lag index) in the alpha bandwidth. Unlike past studies of propofol, ketamine-induced unconsciousness was not associated with increases in the power of frontal alpha rhythms, characteristic cross-frequency coupling patterns of frontal alpha power and slow-oscillation phase, or decreases in coherence in the alpha bandwidth. Like past studies of propofol using undirected and directed phase lag index, ketamine reduced frontal-parietal (functional) and frontal-to-parietal (directional) connectivity in the alpha bandwidth. These results suggest that directional connectivity changes in the alpha bandwidth may be state-related markers of unconsciousness induced by both GABAergic and non-GABAergic anesthetics. PMID:25071473

  6. Niche partitioning due to adaptive foraging reverses effects of nestedness and connectance on pollination network stability.

    PubMed

    Valdovinos, Fernanda S; Brosi, Berry J; Briggs, Heather M; Moisset de Espanés, Pablo; Ramos-Jiliberto, Rodrigo; Martinez, Neo D

    2016-10-01

    Much research debates whether properties of ecological networks such as nestedness and connectance stabilise biological communities while ignoring key behavioural aspects of organisms within these networks. Here, we computationally assess how adaptive foraging (AF) behaviour interacts with network architecture to determine the stability of plant-pollinator networks. We find that AF reverses negative effects of nestedness and positive effects of connectance on the stability of the networks by partitioning the niches among species within guilds. This behaviour enables generalist pollinators to preferentially forage on the most specialised of their plant partners which increases the pollination services to specialist plants and cedes the resources of generalist plants to specialist pollinators. We corroborate these behavioural preferences with intensive field observations of bee foraging. Our results show that incorporating key organismal behaviours with well-known biological mechanisms such as consumer-resource interactions into the analysis of ecological networks may greatly improve our understanding of complex ecosystems. PMID:27600659

  7. "Jeopardy" in Abnormal Psychology.

    ERIC Educational Resources Information Center

    Keutzer, Carolin S.

    1993-01-01

    Describes the use of the board game, Jeopardy, in a college level abnormal psychology course. Finds increased student interaction and improved application of information. Reports generally favorable student evaluation of the technique. (CFR)

  8. Abnormal Uterine Bleeding

    MedlinePlus

    ... Abnormal uterine bleeding is any bleeding from the uterus (through your vagina) other than your normal monthly ... or fibroids (small and large growths) in the uterus can also cause bleeding. Rarely, a thyroid problem, ...

  9. Abnormal Uterine Bleeding FAQ

    MedlinePlus

    ... as cancer of the uterus, cervix, or vagina • Polycystic ovary syndrome How is abnormal bleeding diagnosed? Your health care ... before the fetus can survive outside the uterus. Polycystic Ovary Syndrome: A condition characterized by two of the following ...

  10. Dynamic functional connectivity analysis of Taichong (LR3) acupuncture effects in various brain regions.

    PubMed

    Qiu, Wenjuan; Yan, Bin; He, Hongjian; Tong, Li; Li, Jianxin

    2012-02-25

    The present study conducted a multi-scale dynamic functional connectivity analysis to evaluate dynamic behavior of acupuncture at Taichong (LR3) and sham acupoints surrounding Taichong. Results showed differences in wavelet transform coherence characteristic curves in the declive, precuneus, postcentral gyrus, supramarginal gyrus, and occipital lobe between acupuncture at Taichong and acupuncture at sham acupoints. The differences in characteristic curves revealed that the specific effect of acupuncture existed during the post-acupuncture rest state and lasted for 5 minutes. PMID:25774188

  11. The Effect of Hurricanes on Annual Precipitation in Maryland and the Connection to Global Climate Change

    NASA Technical Reports Server (NTRS)

    Liu, Jackie; Liu, Zhong

    2015-01-01

    Precipitation is a vital aspect of our lives droughts, floods and other related disasters that involve precipitation can cause costly damage in the economic system and general society. Purpose of this project is to determine what, if any effect do hurricanes have on annual precipitation in Maryland Research will be conducted on Marylands terrain, climatology, annual precipitation, and precipitation contributed from hurricanes Possible connections to climate change

  12. Chromosomal Abnormalities and Schizophrenia

    PubMed Central

    BASSETT, ANNE S.; CHOW, EVA W.C.; WEKSBERG, ROSANNA

    2011-01-01

    Schizophrenia is a common and serious psychiatric illness with strong evidence for genetic causation, but no specific loci yet identified. Chromosomal abnormalities associated with schizophrenia may help to understand the genetic complexity of the illness. This paper reviews the evidence for associations between chromosomal abnormalities and schizophrenia and related disorders. The results indicate that 22q11.2 microdeletions detected by fluorescence in-situ hybridization (FISH) are significantly associated with schizophrenia. Sex chromosome abnormalities seem to be increased in schizophrenia but insufficient data are available to indicate whether schizophrenia or related disorders are increased in patients with sex chromosome aneuploidies. Other reports of chromosomal abnormalities associated with schizophrenia have the potential to be important adjuncts to linkage studies in gene localization. Advances in molecular cytogenetic techniques (i.e., FISH) have produced significant increases in rates of identified abnormalities in schizophrenia, particularly in patients with very early age at onset, learning difficulties or mental retardation, or dysmorphic features. The results emphasize the importance of considering behavioral phenotypes, including adult onset psychiatric illnesses, in genetic syndromes and the need for clinicians to actively consider identifying chromosomal abnormalities and genetic syndromes in selected psychiatric patients. PMID:10813803

  13. How music alters a kiss: superior temporal gyrus controls fusiform-amygdalar effective connectivity.

    PubMed

    Pehrs, Corinna; Deserno, Lorenz; Bakels, Jan-Hendrik; Schlochtermeier, Lorna H; Kappelhoff, Hermann; Jacobs, Arthur M; Fritz, Thomas Hans; Koelsch, Stefan; Kuchinke, Lars

    2014-11-01

    While watching movies, the brain integrates the visual information and the musical soundtrack into a coherent percept. Multisensory integration can lead to emotion elicitation on which soundtrack valences may have a modulatory impact. Here, dynamic kissing scenes from romantic comedies were presented to 22 participants (13 females) during functional magnetic resonance imaging scanning. The kissing scenes were either accompanied by happy music, sad music or no music. Evidence from cross-modal studies motivated a predefined three-region network for multisensory integration of emotion, consisting of fusiform gyrus (FG), amygdala (AMY) and anterior superior temporal gyrus (aSTG). The interactions in this network were investigated using dynamic causal models of effective connectivity. This revealed bilinear modulations by happy and sad music with suppression effects on the connectivity from FG and AMY to aSTG. Non-linear dynamic causal modeling showed a suppressive gating effect of aSTG on fusiform-amygdalar connectivity. In conclusion, fusiform to amygdala coupling strength is modulated via feedback through aSTG as region for multisensory integration of emotional material. This mechanism was emotion-specific and more pronounced for sad music. Therefore, soundtrack valences may modulate emotion elicitation in movies by differentially changing preprocessed visual information to the amygdala. PMID:24298171

  14. Mirrored Feedback in Chronic Stroke: Recruitment and Effective Connectivity of Ipsilesional Sensorimotor Networks

    PubMed Central

    Saleh, Soha; Adamovich, Sergei V.; Tunik, Eugene

    2014-01-01

    Background Mirrored feedback has potential as a therapeutic intervention to restore hand function after stroke. However, the functional (effective) connectivity of neural networks involved in processing mirrored feedback after stroke is not known. Objective To determine if regions recruited by mirrored feedback topographically overlap with those involved in control of the paretic hand and to identify the effective connectivity of activated nodes within the mirrored feedback network. Methods Fifteen patients with chronic stroke performed a finger flexion task with their unaffected hand during event-related functional magnetic resonance imaging (fMRI). Real-time hand kinematics was recorded during fMRI and used to actuate hand models presented in virtual reality (VR). Visual feedback of the unaffected hand motion was manipulated pseudorandomly by either actuating the VR hand corresponding to the moving unaffected side (veridical feedback) or the affected side (mirrored feedback). In 2 control conditions, the VR hands were replaced with moving nonanthropomorphic shapes. Results Mirrored feedback was associated with significant activation of regions within and outside the ipsilesional sensorimotor cortex, overlapping with areas engaged when patients performed the task with their affected hand. Effective connectivity analysis showed a significantly interconnected ipsilesional somatosensory and motor cortex in the mirrored feedback condition. Conclusions Mirrored feedback recruits ipsilesional brain areas relevant for control of the affected hand. These data provide a neurophysiological basis by which mirrored feedback may be beneficial as a therapy for restoring function after stroke. PMID:24370569

  15. How music alters a kiss: superior temporal gyrus controls fusiform–amygdalar effective connectivity

    PubMed Central

    Deserno, Lorenz; Bakels, Jan-Hendrik; Schlochtermeier, Lorna H.; Kappelhoff, Hermann; Jacobs, Arthur M.; Fritz, Thomas Hans; Koelsch, Stefan; Kuchinke, Lars

    2014-01-01

    While watching movies, the brain integrates the visual information and the musical soundtrack into a coherent percept. Multisensory integration can lead to emotion elicitation on which soundtrack valences may have a modulatory impact. Here, dynamic kissing scenes from romantic comedies were presented to 22 participants (13 females) during functional magnetic resonance imaging scanning. The kissing scenes were either accompanied by happy music, sad music or no music. Evidence from cross-modal studies motivated a predefined three-region network for multisensory integration of emotion, consisting of fusiform gyrus (FG), amygdala (AMY) and anterior superior temporal gyrus (aSTG). The interactions in this network were investigated using dynamic causal models of effective connectivity. This revealed bilinear modulations by happy and sad music with suppression effects on the connectivity from FG and AMY to aSTG. Non-linear dynamic causal modeling showed a suppressive gating effect of aSTG on fusiform–amygdalar connectivity. In conclusion, fusiform to amygdala coupling strength is modulated via feedback through aSTG as region for multisensory integration of emotional material. This mechanism was emotion-specific and more pronounced for sad music. Therefore, soundtrack valences may modulate emotion elicitation in movies by differentially changing preprocessed visual information to the amygdala. PMID:24298171

  16. Ictal Cardiac Ryhthym Abnormalities

    PubMed Central

    Ali, Rushna

    2016-01-01

    Cardiac rhythm abnormalities in the context of epilepsy are a well-known phenomenon. However, they are under-recognized and often missed. The pathophysiology of these events is unclear. Bradycardia and asystole are preceded by seizure onset suggesting ictal propagation into the cortex impacting cardiac autonomic function, and the insula and amygdala being possible culprits. Sudden unexpected death in epilepsy (SUDEP) refers to the unanticipated death of a patient with epilepsy not related to status epilepticus, trauma, drowning, or suicide. Frequent refractory generalized tonic-clonic seizures, anti-epileptic polytherapy, and prolonged duration of epilepsy are some of the commonly identified risk factors for SUDEP. However, the most consistent risk factor out of these is an increased frequency of generalized tonic–clonic seizures (GTC). Prevention of SUDEP is extremely important in patients with chronic, generalized epilepsy. Since increased frequency of GTCS is the most consistently reported risk factor for SUDEP, effective seizure control is the most important preventive strategy. PMID:27347227

  17. Recovery of cortical effective connectivity and recovery of consciousness in vegetative patients

    PubMed Central

    Rosanova, Mario; Gosseries, Olivia; Casarotto, Silvia; Boly, Mélanie; Casali, Adenauer G.; Bruno, Marie-Aurélie; Mariotti, Maurizio; Boveroux, Pierre; Tononi, Giulio; Laureys, Steven

    2012-01-01

    Patients surviving severe brain injury may regain consciousness without recovering their ability to understand, move and communicate. Recently, electrophysiological and neuroimaging approaches, employing simple sensory stimulations or verbal commands, have proven useful in detecting higher order processing and, in some cases, in establishing some degree of communication in brain-injured subjects with severe impairment of motor function. To complement these approaches, it would be useful to develop methods to detect recovery of consciousness in ways that do not depend on the integrity of sensory pathways or on the subject's ability to comprehend or carry out instructions. As suggested by theoretical and experimental work, a key requirement for consciousness is that multiple, specialized cortical areas can engage in rapid causal interactions (effective connectivity). Here, we employ transcranial magnetic stimulation together with high-density electroencephalography to evaluate effective connectivity at the bedside of severely brain injured, non-communicating subjects. In patients in a vegetative state, who were open-eyed, behaviourally awake but unresponsive, transcranial magnetic stimulation triggered a simple, local response indicating a breakdown of effective connectivity, similar to the one previously observed in unconscious sleeping or anaesthetized subjects. In contrast, in minimally conscious patients, who showed fluctuating signs of non-reflexive behaviour, transcranial magnetic stimulation invariably triggered complex activations that sequentially involved distant cortical areas ipsi- and contralateral to the site of stimulation, similar to activations we recorded in locked-in, conscious patients. Longitudinal measurements performed in patients who gradually recovered consciousness revealed that this clear-cut change in effective connectivity could occur at an early stage, before reliable communication was established with the subject and before the

  18. The Effect of Criticism on Functional Brain Connectivity and Associations with Neuroticism

    PubMed Central

    Servaas, Michelle Nadine; Riese, Harriëtte; Renken, Remco Jan; Marsman, Jan-Bernard Cornelis; Lambregs, Johan; Ormel, Johan; Aleman, André

    2013-01-01

    Neuroticism is a robust personality trait that constitutes a risk factor for psychopathology, especially anxiety disorders and depression. High neurotic individuals tend to be more self-critical and are overly sensitive to criticism by others. Hence, we used a novel resting-state paradigm to investigate the effect of criticism on functional brain connectivity and associations with neuroticism. Forty-eight participants completed the NEO Personality Inventory Revised (NEO-PI-R) to assess neuroticism. Next, we recorded resting state functional magnetic resonance imaging (rsfMRI) during two sessions. We manipulated the second session before scanning by presenting three standardized critical remarks through headphones, in which the subject was urged to please lie still in the scanner. A seed-based functional connectivity method and subsequent clustering were used to analyse the resting state data. Based on the reviewed literature related to criticism, we selected brain regions associated with self-reflective processing and stress-regulation as regions of interest. The findings showed enhanced functional connectivity between the clustered seed regions and brain areas involved in emotion processing and social cognition during the processing of criticism. Concurrently, functional connectivity was reduced between these clusters and brain structures related to the default mode network and higher-order cognitive control. Furthermore, individuals scoring higher on neuroticism showed altered functional connectivity between the clustered seed regions and brain areas involved in the appraisal, expression and regulation of negative emotions. These results may suggest that the criticized person is attempting to understand the beliefs, perceptions and feelings of the critic in order to facilitate flexible and adaptive social behavior. Furthermore, multiple aspects of emotion processing were found to be affected in individuals scoring higher on neuroticism during the processing of

  19. Magnetic Resonance Field Strength Effects on Diffusion Measures and Brain Connectivity Networks

    PubMed Central

    Zhan, Liang; Mueller, Bryon A.; Jahanshad, Neda; Jin, Yan; Lenglet, Christophe; Yacoub, Essa; Sapiro, Guillermo; Ugurbil, Kamil; Harel, Noam; Toga, Arthur W.; Lim, Kelvin O.

    2013-01-01

    Abstract The quest to map brain connectivity is being pursued worldwide using diffusion imaging, among other techniques. Even so, we know little about how brain connectivity measures depend on the magnetic field strength of the scanner. To investigate this, we scanned 10 healthy subjects at 7 and 3 tesla—using 128-gradient high-angular resolution diffusion imaging. For each subject and scan, whole-brain tractography was used to estimate connectivity between 113 cortical and subcortical regions. We examined how scanner field strength affects (i) the signal-to-noise ratio (SNR) of the non-diffusion-sensitized reference images (b0); (ii) diffusion tensor imaging (DTI)-derived fractional anisotropy (FA), mean, radial, and axial diffusivity (MD/RD/AD), in atlas-defined regions; (iii) whole-brain tractography; (iv) the 113×113 brain connectivity maps; and (v) five commonly used network topology measures. We also assessed effects of the multi-channel reconstruction methods (sum-of-squares, SOS, at 7T; adaptive recombine, AC, at 3T). At 7T with SOS, the b0 images had 18.3% higher SNR than with 3T-AC. FA was similar for most regions of interest (ROIs) derived from an online DTI atlas (ICBM81), but higher at 7T in the cerebral peduncle and internal capsule. MD, AD, and RD were lower at 7T for most ROIs. The apparent fiber density between some subcortical regions was greater at 7T-SOS than 3T-AC, with a consistent connection pattern overall. Suggesting the need for caution, the recovered brain network was apparently more efficient at 7T, which cannot be biologically true as the same subjects were assessed. Care is needed when comparing network measures across studies, and when interpreting apparently discrepant findings. PMID:23205551

  20. Effect of rotational shepherding on demographic and genetic connectivity of calcareous grassland plants.

    PubMed

    Rico, Yessica; Boehmer, Hans Juergen; Wagner, Helene H

    2014-04-01

    Response to habitat fragmentation may not be generalized among species, in particular for plant communities with a variety of dispersal traits. Calcareous grasslands are one of the most species-rich habitats in Central Europe, but abandonment of traditional management has caused a dramatic decline of calcareous grassland species. In the Southern Franconian Alb in Germany, reintroduction of rotational shepherding in previously abandoned grasslands has restored species diversity, and it has been suggested that sheep support seed dispersal among grasslands. We tested the effect of rotational shepherding on demographic and genetic connectivity of calcareous grassland specialist plants and whether the response of plant populations to shepherding was limited to species dispersed by animals (zoochory). Specifically, we tested competing dispersal models and source and focal patch properties to explain landscape connectivity with patch-occupancy data of 31 species. We fitted the same connectivity models to patch occupancy and nuclear microsatellite data for the herb Dianthus carthusianorum (Carthusian pink). For 27 species, patch connectivity was explained by dispersal by rotational shepherding regardless of adaptations to zoochory, whereas population size (16% species) and patch area (0% species) of source patches were not important predictors of patch occupancy in most species. [Correction made after online publication, February 25, 2014: Population size and patch area percentages were mistakenly inverted, and have now been fixed.] Microsite diversity of focal patches significantly increased the model variance explained by patch occupancy in 90% of the species. For D. carthusianorum, patch connectivity through rotational shepherding explained both patch occupancy and population genetic diversity. Our results suggest shepherding provides dispersal for multiple plant species regardless of their dispersal adaptations and thus offers a useful approach to restore plant

  1. Epilepsy caused by an abnormal alternative splicing with dosage effect of the SV2A gene in a chicken model.

    PubMed

    Douaud, Marine; Feve, Katia; Pituello, Fabienne; Gourichon, David; Boitard, Simon; Leguern, Eric; Coquerelle, Gérard; Vieaud, Agathe; Batini, Cesira; Naquet, Robert; Vignal, Alain; Tixier-Boichard, Michèle; Pitel, Frédérique

    2011-01-01

    Photosensitive reflex epilepsy is caused by the combination of an individual's enhanced sensitivity with relevant light stimuli, such as stroboscopic lights or video games. This is the most common reflex epilepsy in humans; it is characterized by the photoparoxysmal response, which is an abnormal electroencephalographic reaction, and seizures triggered by intermittent light stimulation. Here, by using genetic mapping, sequencing and functional analyses, we report that a mutation in the acceptor site of the second intron of SV2A (the gene encoding synaptic vesicle glycoprotein 2A) is causing photosensitive reflex epilepsy in a unique vertebrate model, the Fepi chicken strain, a spontaneous model where the neurological disorder is inherited as an autosomal recessive mutation. This mutation causes an aberrant splicing event and significantly reduces the level of SV2A mRNA in homozygous carriers. Levetiracetam, a second generation antiepileptic drug, is known to bind SV2A, and SV2A knock-out mice develop seizures soon after birth and usually die within three weeks. The Fepi chicken survives to adulthood and responds to levetiracetam, suggesting that the low-level expression of SV2A in these animals is sufficient to allow survival, but does not protect against seizures. Thus, the Fepi chicken model shows that the role of the SV2A pathway in the brain is conserved between birds and mammals, in spite of a large phylogenetic distance. The Fepi model appears particularly useful for further studies of physiopathology of reflex epilepsy, in comparison with induced models of epilepsy in rodents. Consequently, SV2A is a very attractive candidate gene for analysis in the context of both mono- and polygenic generalized epilepsies in humans. PMID:22046416

  2. A simulation of three-dimensional systolic flow dynamics in a spherical ventricle: effects of abnormal wall motion.

    PubMed

    Gonzalez, E; Schoephoerster, R T

    1996-01-01

    Alterations in left ventricle (LV) wall motion induced by ischemia will affect flow dynamics, and these altered flow fields can be used to evaluate LV pumping efficiency. LV chamber flow fields were obtained in this study by solving the discretized three-dimensional Navier-Stokes equations for viscous, incompressible unsteady flow by using the finite analytic method. Several cases of abnormal wall motion (AWM) were simulated by a manipulation of the boundary conditions to produce regions of hypokinesis, akinesis, and dyskinesis. These solutions were used to determine the central ejection region (CER), defined as the region of flow domain in which the obtained velocity field vectors are aligned +/- 3 degrees from the LV long axis. A CER coefficient was computed from information on the location and orientation of the CER within the LV cavity. Contraction of the spherical ventricle produced a vector field that was symmetric with respect to the long axis. For the simulations of AWM, an asymmetrical flow pattern developed, became more pronounced with increasing severity of AWM, and resulted in a shorter CER that shifted toward the ischemic region. The CER coefficients decreased monotonically with increased severity in AWM from 0.948 in the normal case to a low of 0.164 for the most severe case of AWM. The CER coefficient quantitatively displayed the sensitivity of the flow patterns to even moderate degrees of hypokinesis. In addition, visualization of the three-dimensional flow field reinforced the necessity of three-dimensional simulations to capture aspects of the flow that existing methods of two-dimensional flow imaging that use ultrasound may miss. PMID:8669717

  3. The Effects of Long Duration Bed Rest on Brain Functional Connectivity and Sensorimotor Functioning

    NASA Technical Reports Server (NTRS)

    Cassady, K.; Koppelmans, V.; De Dios, Y.; Stepanyan, V.; Szecsy, D.; Gadd, N.; Wood, S.; Reuter-Lorenz, P.; Castenada, R. Riascos; Kofman, I.; Bloomberg, J.; Mulavara, A; Seidler, R.

    2016-01-01

    Long duration spaceflight has been associated with detrimental alterations in human sensorimotor functioning. Prolonged exposure to a head-down tilt (HDT) position during long duration bed rest can resemble several effects of the microgravity environment such as reduced sensory inputs, body unloading and increased cephalic fluid distribution. The question of whether microgravity affects other central nervous system functions such as brain functional connectivity and its relationship with behavior is largely unknown, but of importance to the health and performance of astronauts both during and post-flight. In the present study, we investigate the effects of prolonged exposure to HDT bed rest on resting state brain functional connectivity and its association with behavioral changes in 17 male participants. To validate that our findings were not due to confounding factors such as time or task practice, we also acquired resting state functional magnetic resonance imaging (rs-fMRI) and behavioral measurements from 14 normative control participants at four time points. Bed rest participants remained in bed with their heads tilted down six degrees below their feet for 70 consecutive days. Rs-fMRI and behavioral data were obtained at seven time points averaging around: 12 and 8 days prior to bed rest; 7, 50, and 70 days during bed rest; and 8 and 12 days after bed rest. 70 days of HDT bed rest resulted in significant increases in functional connectivity during bed rest followed by a reversal of changes in the post bed rest recovery period between motor cortical and somatosensory areas of the brain. In contrast, decreases in connectivity were observed between temporoparietal regions. Furthermore, post-hoc correlation analyses revealed a significant relationship between motor-somatosensory network connectivity and standing balance performance changes; participants that exhibited the greatest increases in connectivity strength showed the least deterioration in postural

  4. Effects of a Wildfire on Road-stream Connectivity and Road Surface Erosion

    NASA Astrophysics Data System (ADS)

    Sosa-Perez, Gabriel; MacDonald, Lee

    2016-04-01

    Unpaved roads generate large amounts of sediment per unit area, and the impact of these high erosion rates depends on how much of this sediment is delivered to streams. In the western USA typically around 10-30% of the road length is connected to a stream, and this proportion tends to increase with increasing precipitation. Wildfires can greatly increase surface runoff and erosion rates, but we know of no studies that have evaluated how fires affect road surface erosion and road-stream connectivity. Hence the objective of this study was to quantify how: 1) fire severity affects the amount of road surface rilling, sediment deposition, and road-stream connectivity; and 2) how these effects are modified by road segment characteristics. The study area was 6.8 km of the unpaved Old Flowers Road just west of Fort Collins, Colorado, USA, as the forests along this road had burned in the 2012 High Park fire. Detailed data were collected for 141 hydrologically distinct road segments, including the hillslopes above the road, road segment characteristics, and the drainage features leaving the road. Nearly all of the road segments had a planar design, and mean segment length and active width were 50 m and 2.4 m, respectively. The road segments below areas burned at high and moderate severity had significantly more and larger rills than road segments below areas burned at low severity, and this can be attributed to the greater surface runoff from upslope. Road segment slope was an increasingly important control on the amount of rilling as burn severity increased, while the flatter segments tended to capture the sediment eroded from upslope. Three-quarters of the road segments had only a single drainage feature, indicating that the road generally collected and concentrated all of the dispersed runoff from upslope. All of the road segments in areas burned at high and moderate severity and 78% of the segments in areas burned at low severity were connected to the stream. These

  5. Effects of Connectivity and Recurrent Local Disturbances on Community Structure and Population Density in Experimental Metacommunities

    PubMed Central

    Carrara, Francesco; Rinaldo, Andrea; Holyoak, Marcel

    2011-01-01

    Metacommunity theory poses that the occurrence and abundance of species is a product of local factors, including disturbance, and regional factors, like dispersal among patches. While metacommunity ideas have been broadly tested there is relatively little work on metacommunities subject to disturbance. We focused on how localized disturbance and dispersal interact to determine species composition in metacommunities. Experiments conducted in simple two-patch habitats containing eight protozoa and rotifer species tested how dispersal altered community composition in both communities that were disturbed and communities that connected to refuge communities not subject to disturbance. While disturbance lowered population densities, in disturbed patches connected to undisturbed patches this was ameliorated by immigration. Furthermore, species with high dispersal abilities or growth rates showed the fastest post-disturbance recovery in presence of immigration. Connectivity helped to counteract the negative effect of disturbances on local populations, allowing mass-effect-driven dispersal of individuals from undisturbed to disturbed patches. In undisturbed patches, however, local population sizes were not significantly reduced by emigration. The absence of a cost of dispersal for undisturbed source populations is consistent with a lack of complex demography in our system, such as age- or sex-specific emigration. Our approach provides an improved way to separate components of population growth from organisms' movement in post-disturbance recovery of (meta)communities. Further studies are required in a variety of ecosystems to investigate the transient dynamics resulting from disturbance and dispersal. PMID:21559336

  6. Topological changes of the effective connectivity during the working memory training.

    PubMed

    Sun, Yu; Taya, Fumihiko; Chen, Yu; Delgado Martinez, Ignacio; Thakor, Nitish; Bezerianos, Anastasios

    2014-01-01

    Working memory (WM) refers to the retention of information over a short period of time. Accumulated evidence showed that training WM would lead to beneficial effects in untrained tasks, which could be attributed to the strengthening of the functional connections between brain regions through repeated training task. In this proof of concept investigation, we applied a graph theoretical approach to analyze the early changes of functional connectivity from two subjects undergoing a spatial n-back WM training task for three continuous days. A significant decreased clustering coefficient and normalized shortest path length was revealed, suggesting a reduced local efficiency with an increased global efficiency after WM training. Our findings thereby provide insightful implications for understanding the mechanisms of brain dynamics in cognitive training. PMID:25571423

  7. [The effect of monoamine oxidase inhibition on formation, fixation and reproduction of temporary connections].

    PubMed

    Kruglikov, R I; Getsova, V M; Maĭzelis, M Ia

    1975-01-01

    An administration of 100 to 300 mg/kg doses of iprazid to rats and mice leads in 24 hours to a considerably higher serotonin and noradrenaline content in the brain. Defensive conditioning against this background proceeds in the same way as in control animals but the retention of elaborated reflexes is sharply disturbed. A similar effect is produced by 5-oxytryptophane. An iprazid administration after conditioning does not disturb the retention and subsequent achievement of the reflex. Inclusion of S35-methionine in the total proteins of the mice brain does not change under the influence of iprazid. A conclusion has been drawn that inhibition of monoaminoxidase by iprazid does not prevent the formation and reproduction of temporary connections, but deeply disturbs their fixation. It is suggested that the revealed disturbances of fixation of temporary connections are due to the accumulation of serotonin in the brain, which suppresses the protein synthesis in the synaptosomes or that of specific proteins. PMID:1210682

  8. The polymer converter for effectively connecting polymer with silica optical fibres

    NASA Astrophysics Data System (ADS)

    Pura-Pawlikowska, P.; Dudek, M.; Wonko, R.; Marć, P.; Kujawińska, M.; Jaroszewicz, L. R.

    2016-09-01

    We present a micrometer-size polymer converter (microbridge) for connecting polymer optical fibres with silica fibres. The procedure of preparing such microstructure is based on a process of photopolymerization. A polymer converter grows as an extension of the fibres' cores due to a self-guiding effect of the light beam in a photopolymerizable medium. Since the polymer microbridge has refractive index greater inside than outside, such a structure works as a waveguide leading the light beam between connected optical fibres. By selection of time of light exposition to the mixture and optical power of the incident light beam, it is possible to obtain a polymer converter with very good optical and mechanical characteristics. Possibility of using polymer microbridges grown directly from the fibres' core as coupling elements between silica and polymer fibres is a good alternative for obtaining permanent coupling of such fibres.

  9. The effect of eggshell apex abnormalities on table egg quality during storage in 2 seasons of the year.

    PubMed

    Brandão, M D M; Santos, F F; Machado, L S; Verinaud, M S; Oliveira, J M; Soares, N M; Nascimento, E R; Pereira, V L A

    2014-10-01

    Mycoplasma synoviae infection of hens has been associated with problems of eggshell quality called eggshell apex abnormalities (EAA). Little is known about the quality of EAA eggs from a commercial point of view, especially during their storage. The study aimed to examine the differences between EAA and normal eggs during storage under controlled conditions in 2 seasons, summer and winter, by comparing internal and external quality parameters. In a conventional egg production farm with white laying hens of varying ages in the city of Bastos, state of São Paulo, Brazil, 232 eggs were used in the summer season and 400 eggs in the winter season. Half of the eggs had EAA, and the other half were considered normal eggs for each season. The eggs were analyzed at 2, 7, 14, 21, and 28 d after being laid and stored from 24.6 to 25.8°C in summer and from 24 to 25°C in winter. There was no difference (P > 0.05) in the average egg weight between EAA and normal eggs at any studied time point, but in both seasons, the weight loss in EAA eggs was higher than in normal eggs. The losses in Haugh unit scores from the first to the last measurements were approximately 40% regardless of egg type or season of production. In comparing eggshell thickness, only the apices of the EAA eggs were thinner (P < 0.0001) than normal eggs in the summer, but in the winter, the EAA egg apices (P < 0.0001) and sides (P = 0.03) were both thinner. The presence of EAA did not affect the eggshell weight (P > 0.05) or eggshell percentage (P > 0.05). The eggshell strength of the EAA eggs was lower (P < 0.0001) than normal eggs in both the summer (16.57%) and winter (19.86%). The presence of EAA did not affect the internal quality of the egg, but was related to a greater loss of external quality and weight during storage. PMID:25085932

  10. Preliminary study of the effect of abnormal savda munziq on TGF-β1 and Smad7 expression in hypertrophic scar fibroblasts

    PubMed Central

    Wang, Hujun; Gao, Weicheng; Kong, Menglong; Li, Nan; Ma, Shaolin

    2015-01-01

    Background: To study the effect of abnormal savda munziq (ASMq) on TGF-β1 and Smad7 expression in hypertrophic scar fibroblasts (HSFs) and to preliminarily assess the function of abnormal savda munziq in hypertrophic scar formation at the molecular biology level. Methods: HSFs were cultured in vitro. RT-PCR and Western-blot were used to investigate the influence of 48-h treatment with ASMq at different concentrations (0 mg/mL, 0.1 mg/mL, 0.4 mg/mL, and 0.7 mg/mL) on TGF-β1 and Smad7 mRNA and protein expression levels. Results: After 48-h treatment with ASMq, the expression of TGF-β1 mRNA and protein gradually decreased in HSFs as the concentration increased. In contrary, Smad7 mRNA and protein expression were positively correlated with ASMq concentration. Conclusions: ASMq reduces TGF-β1, increases Smad7 mRNA and protein expression through regulating TGFβ-1/Smad signaling pathway, inhibiting HSFs proliferation and reducing extracellular collagen deposition. PMID:25785025

  11. About connections.

    PubMed

    Rockland, Kathleen S

    2015-01-01

    Despite the attention attracted by "connectomics", one can lose sight of the very real questions concerning "What are connections?" In the neuroimaging community, "structural" connectivity is ground truth and underlying constraint on "functional" or "effective" connectivity. It is referenced to underlying anatomy; but, as increasingly remarked, there is a large gap between the wealth of human brain mapping and the relatively scant data on actual anatomical connectivity. Moreover, connections have typically been discussed as "pairwise", point x projecting to point y (or: to points y and z), or more recently, in graph theoretical terms, as "nodes" or regions and the interconnecting "edges". This is a convenient shorthand, but tends not to capture the richness and nuance of basic anatomical properties as identified in the classic tradition of tracer studies. The present short review accordingly revisits connectional weights, heterogeneity, reciprocity, topography, and hierarchical organization, drawing on concrete examples. The emphasis is on presynaptic long-distance connections, motivated by the intention to probe current assumptions and promote discussions about further progress and synthesis. PMID:26042001

  12. Connectivity: A Framework for Understanding Effective Language Teaching in Face-to-Face and Online Learning Communities

    ERIC Educational Resources Information Center

    Senior, Rose

    2010-01-01

    This is an exploratory paper that uses the construct of connectivity to examine the nature of effective language teaching and learning in both face-to-face and online learning environments. Broader in scope than Siemens' notion of connectivism, the term connectivity accommodates both transmission approaches to teaching and learning and social…

  13. Oppositional COMT Val158Met effects on resting state functional connectivity in adolescents and adults.

    PubMed

    Meyer, Bernhard M; Huemer, Julia; Rabl, Ulrich; Boubela, Roland N; Kalcher, Klaudius; Berger, Andreas; Banaschewski, Tobias; Barker, Gareth; Bokde, Arun; Büchel, Christian; Conrod, Patricia; Desrivières, Sylvane; Flor, Herta; Frouin, Vincent; Gallinat, Jurgen; Garavan, Hugh; Heinz, Andreas; Ittermann, Bernd; Jia, Tianye; Lathrop, Mark; Martinot, Jean-Luc; Nees, Frauke; Rietschel, Marcella; Smolka, Michael N; Bartova, Lucie; Popovic, Ana; Scharinger, Christian; Sitte, Harald H; Steiner, Hans; Friedrich, Max H; Kasper, Siegfried; Perkmann, Thomas; Praschak-Rieder, Nicole; Haslacher, Helmuth; Esterbauer, Harald; Moser, Ewald; Schumann, Gunter; Pezawas, Lukas

    2016-01-01

    Prefrontal dopamine levels are relatively increased in adolescence compared to adulthood. Genetic variation of COMT (COMT Val158Met) results in lower enzymatic activity and higher dopamine availability in Met carriers. Given the dramatic changes of synaptic dopamine during adolescence, it has been suggested that effects of COMT Val158Met genotypes might have oppositional effects in adolescents and adults. The present study aims to identify such oppositional COMT Val158Met effects in adolescents and adults in prefrontal brain networks at rest. Resting state functional connectivity data were collected from cross-sectional and multicenter study sites involving 106 healthy young adults (mean age 24 ± 2.6 years), gender matched to 106 randomly chosen 14-year-olds. We selected the anterior medial prefrontal cortex (amPFC) as seed due to its important role as nexus of the executive control and default mode network. We observed a significant age-dependent reversal of COMT Val158Met effects on resting state functional connectivity between amPFC and ventrolateral as well as dorsolateral prefrontal cortex, and parahippocampal gyrus. Val homozygous adults exhibited increased and adolescents decreased connectivity compared to Met homozygotes for all reported regions. Network analyses underscored the importance of the parahippocampal gyrus as mediator of observed effects. Results of this study demonstrate that adolescent and adult resting state networks are dose-dependently and diametrically affected by COMT genotypes following a hypothetical model of dopamine function that follows an inverted U-shaped curve. This study might provide cues for the understanding of disease onset or dopaminergic treatment mechanisms in major neuropsychiatric disorders such as schizophrenia and attention deficit hyperactivity disorder. PMID:25319752

  14. Atypical Lexicosemantic Function of Extrastriate Cortex in Autism Spectrum Disorder: Evidence from Functional and Effective Connectivity

    PubMed Central

    Shen, Mark D.; Shih, Patricia; Öttl, Birgit; Keehn, Brandon; Leyden, Kelly M.; Gaffrey, Michael S.; Müller, Ralph-Axel

    2012-01-01

    Previous studies have suggested atypically enhanced activity of visual cortex during language processing in autism spectrum disorder (ASD). However, it remains unclear whether visual cortical participation reflects isolated processing within posterior regions or functional cooperation with distal brain regions, such as left inferior frontal gyrus (LIFG). We addressed this question using functional connectivity MRI (fcMRI) and structural equation modeling in 14 adolescents and adults with ASD and 14 matched typically developing (TD) participants. Data were analyzed to isolate low-frequency intrinsic fluctuations, by regressing out effects of a semantic decision task. For a right extrastriate seed derived from the strongest cluster of atypical activation in the ASD group, widespread effects of increased connectivity in prefrontal and medial frontal lobes bilaterally were observed for the ASD group, compared to the TD group. A second analysis for a seed in LIFG, derived from pooled activation effects in both groups, also yielded widespread effects of overconnectivity in the ASD group, especially in temporal lobes. Structural equation modeling showed that whereas right extrastriate cortex did not impact function of language regions (left and right IFG, left middle temporal gyrus) in the TD model, it was an integral part of a language circuit in the ASD group. These results suggest that atypical extrastriate activation during language processing in ASD reflects integrative (not isolated) processing. Furthermore, our findings are inconsistent with previous reports of functional underconnectivity in ASD, probably related to removal of task effects required to isolate intrinsic low-frequency fluctuations. PMID:22699044

  15. Evaluating the effectiveness of restoring longitudinal connectivity for stream fish communities: towards a more holistic approach.

    PubMed

    Tummers, Jeroen S; Hudson, Steve; Lucas, Martyn C

    2016-11-01

    A more holistic approach towards testing longitudinal connectivity restoration is needed in order to establish that intended ecological functions of such restoration are achieved. We illustrate the use of a multi-method scheme to evaluate the effectiveness of 'nature-like' connectivity restoration for stream fish communities in the River Deerness, NE England. Electric-fishing, capture-mark-recapture, PIT telemetry and radio-telemetry were used to measure fish community composition, dispersal, fishway efficiency and upstream migration respectively. For measuring passage and dispersal, our rationale was to evaluate a wide size range of strong swimmers (exemplified by brown trout Salmo trutta) and weak swimmers (exemplified by bullhead Cottus perifretum) in situ in the stream ecosystem. Radio-tracking of adult trout during the spawning migration showed that passage efficiency at each of five connectivity-restored sites was 81.3-100%. Unaltered (experimental control) structures on the migration route had a bottle-neck effect on upstream migration, especially during low flows. However, even during low flows, displaced PIT tagged juvenile trout (total n=153) exhibited a passage efficiency of 70.1-93.1% at two nature-like passes. In mark-recapture experiments juvenile brown trout and bullhead tagged (total n=5303) succeeded in dispersing upstream more often at most structures following obstacle modification, but not at the two control sites, based on a Laplace kernel modelling approach of observed dispersal distance and barrier traverses. Medium-term post-restoration data (2-3years) showed that the fish assemblage remained similar at five of six connectivity-restored sites and two control sites, but at one connectivity-restored headwater site previously inhabited by trout only, three native non-salmonid species colonized. We conclude that stream habitat reconnection should support free movement of a wide range of species and life stages, wherever retention of such

  16. Functional and effective hippocampal-neocortical connectivity during construction and elaboration of autobiographical memory retrieval.

    PubMed

    McCormick, Cornelia; St-Laurent, Marie; Ty, Ambrose; Valiante, Taufik A; McAndrews, Mary Pat

    2015-05-01

    Autobiographical memory (AM) provides the opportunity to study interactions among brain areas that support the search for a specific episodic memory (construction), and the later experience of mentally reliving it (elaboration). While the hippocampus supports both construction and elaboration, it is unclear how hippocampal-neocortical connectivity differs between these stages, and how this connectivity involves the anterior and posterior segments of the hippocampus, as these have been considered to support the retrieval of general concepts and recollection processes, respectively. We acquired fMRI data in 18 healthy participants during an AM retrieval task in which participants were asked to access a specific AM (construction) and then to recollect it by recovering as many episodic details as possible (elaboration). Using multivariate analytic techniques, we examined changes in functional and effective connectivity of hippocampal-neocortical interactions during these phases of AM retrieval. We found that the left anterior hippocampus interacted with frontal areas during construction and bilateral posterior hippocampi with visual perceptual areas during elaboration, indicating key roles for both hippocampi in coordinating transient neocortical networks at both AM stages. Our findings demonstrate the importance of direct interrogation of hippocampal-neocortical interactions to better illuminate the neural dynamics underlying complex cognitive tasks such as AM retrieval. PMID:24275829

  17. Effective connectivity during animacy perception – dynamic causal modelling of Human Connectome Project data

    PubMed Central

    Hillebrandt, Hauke; Friston, Karl J.; Blakemore, Sarah-Jayne

    2014-01-01

    Biological agents are the most complex systems humans have to model and predict. In predictive coding, high-level cortical areas inform sensory cortex about incoming sensory signals, a comparison between the predicted and actual sensory feedback is made, and information about unpredicted sensory information is passed forward to higher-level areas. Predictions about animate motion – relative to inanimate motion – should result in prediction error and increase signal passing from lower level sensory area MT+/V5, which is responsive to all motion, to higher-order posterior superior temporal sulcus (pSTS), which is selectively activated by animate motion. We tested this hypothesis by investigating effective connectivity in a large-scale fMRI dataset from the Human Connectome Project. 132 participants viewed animations of triangles that were designed to move in a way that appeared animate (moving intentionally), or inanimate (moving in a mechanical way). We found that forward connectivity from V5 to the pSTS increased, and inhibitory self-connection in the pSTS decreased, when viewing intentional motion versus inanimate motion. These prediction errors associated with animate motion may be the cause for increased attention to animate stimuli found in previous studies. PMID:25174814

  18. Effective connectivity during animacy perception--dynamic causal modelling of Human Connectome Project data.

    PubMed

    Hillebrandt, Hauke; Friston, Karl J; Blakemore, Sarah-Jayne

    2014-01-01

    Biological agents are the most complex systems humans have to model and predict. In predictive coding, high-level cortical areas inform sensory cortex about incoming sensory signals, a comparison between the predicted and actual sensory feedback is made, and information about unpredicted sensory information is passed forward to higher-level areas. Predictions about animate motion - relative to inanimate motion - should result in prediction error and increase signal passing from lower level sensory area MT+/V5, which is responsive to all motion, to higher-order posterior superior temporal sulcus (pSTS), which is selectively activated by animate motion. We tested this hypothesis by investigating effective connectivity in a large-scale fMRI dataset from the Human Connectome Project. 132 participants viewed animations of triangles that were designed to move in a way that appeared animate (moving intentionally), or inanimate (moving in a mechanical way). We found that forward connectivity from V5 to the pSTS increased, and inhibitory self-connection in the pSTS decreased, when viewing intentional motion versus inanimate motion. These prediction errors associated with animate motion may be the cause for increased attention to animate stimuli found in previous studies. PMID:25174814

  19. Fast Dynamics of Cortical Functional and Effective Connectivity during Word Reading

    PubMed Central

    Bedo, Nicolas; Ribary, Urs; Ward, Lawrence M.

    2014-01-01

    We describe for the first time the fast dynamics of functional and effective (causal) connectivity during word reading. Independent component analysis of high-density EEG recorded during a word reading task recovered multiple sources of electrical brain activity previously identified by fMRI and PET. Results confirmed the ventral occipito-temporal cortex (vOT) as a central hub for word reading, showing a progression of theta-band (3–7 Hz) and gamma-band (30–50 Hz) phase synchronization and directed theta-band and gamma-band information flow with both early visual areas and high-level language-processing areas. These results highlight the interplay between local and long-distance neural dynamics involved at each stage of the reading process. Moreover, these measures of functional and causal connectivity dynamics may be used as a benchmark for comparison with clinical populations (e.g. individuals with developmental dyslexia), such that disturbances in connectivity dynamics may provide insight as to underlying neurological problems with language processing, and their potential remediation. PMID:24551193

  20. Effect of white matter disease on functional connections in the aging brain.

    PubMed Central

    Leuchter, A F; Dunkin, J J; Lufkin, R B; Anzai, Y; Cook, I A; Newton, T F

    1994-01-01

    Periventricular white matter hyperintensities (PVHs) seen on T2 weighted MRI studies are common in elderly people and often represent demyelination of fibres. Damage to these fibres could lead to functional disconnection between brain regions. Electroencephalographic coherence, a measure of shared electrical activity between regions, was examined to determine if there was evidence for such disconnection. Twenty two subjects with clinically diagnosed dementia of the Alzheimer's type, 16 with multi-infarct dementia, and 18 normal controls were studied. It was hypothesised that coherence between areas presumably linked by fibres that traverse the periventricular region would be decreased in subjects with PVHs, and that PVHs would have a stronger association with decreased coherence than clinical diagnosis. It was also hypothesised that coherence between areas presumably connected by long corticocortical tracts that are neuroanatomically separated from the ventricles would be low in patients with Alzheimer's disease because of pyramidal cell death in this group, but would not be affected by the presence of PVHs. Patients with PVHs in fact had lower coherence than those without PVHs in the pre-Rolandic and post-Rolandic areas, where connecting fibres traverse the periventricular region. There was no effect of PVHs, however, on coherence between areas separated by the Rolandic fissure that were connected by long corticocortical tracts; this coherence was lowest among the patients with Alzheimer's disease. These patterns of association suggest that coherence may detect different types of neurophysiological "disconnection," and may be sensitive to selective damage to different fibre pathways. Images PMID:7964810

  1. Effective connectivity reveals right-hemisphere dominance in audiospatial perception: implications for models of spatial neglect.

    PubMed

    Dietz, Martin J; Friston, Karl J; Mattingley, Jason B; Roepstorff, Andreas; Garrido, Marta I

    2014-04-01

    Detecting the location of salient sounds in the environment rests on the brain's ability to use differences in sounds arriving at both ears. Functional neuroimaging studies in humans indicate that the left and right auditory hemispaces are coded asymmetrically, with a rightward attentional bias that reflects spatial attention in vision. Neuropsychological observations in patients with spatial neglect have led to the formulation of two competing models: the orientation bias and right-hemisphere dominance models. The orientation bias model posits a symmetrical mapping between one side of the sensorium and the contralateral hemisphere, with mutual inhibition of the ipsilateral hemisphere. The right-hemisphere dominance model introduces a functional asymmetry in the brain's coding of space: the left hemisphere represents the right side, whereas the right hemisphere represents both sides of the sensorium. We used Dynamic Causal Modeling of effective connectivity and Bayesian model comparison to adjudicate between these alternative network architectures, based on human electroencephalographic data acquired during an auditory location oddball paradigm. Our results support a hemispheric asymmetry in a frontoparietal network that conforms to the right-hemisphere dominance model. We show that, within this frontoparietal network, forward connectivity increases selectively in the hemisphere contralateral to the side of sensory stimulation. We interpret this finding in light of hierarchical predictive coding as a selective increase in attentional gain, which is mediated by feedforward connections that carry precision-weighted prediction errors during perceptual inference. This finding supports the disconnection hypothesis of unilateral neglect and has implications for theories of its etiology. PMID:24695717

  2. Numerical and experimental study of the 3D effect on connecting arm of vertical axis tidal current turbine

    NASA Astrophysics Data System (ADS)

    Guo, Wei; Kang, Hai-gui; Chen, Bing; Xie, Yu; Wang, Yin

    2016-03-01

    Vertical axis tidal current turbine is a promising device to extract energy from ocean current. One of the important components of the turbine is the connecting arm, which can bring about a significant effect on the pressure distribution along the span of the turbine blade, herein we call it 3D effect. However, so far the effect is rarely reported in the research, moreover, in numerical simulation. In the present study, a 3D numerical model of the turbine with the connecting arm was developed by using FLUENT software compiling the UDF (User Defined Function) command. The simulation results show that the pressure distribution along the span of blade with the connecting arm model is significantly different from those without the connecting arm. To facilitate the validation of numerical model, the laboratory experiment has been carried out by using three different types of NACA aerofoil connecting arm and circle section connecting arm. And results show that the turbine with NACA0012 connecting arm has the best start-up performance which is 0.346 m/s and the peak point of power conversion coefficient is around 0.33. A further study has been performed and a conclusion is drawn that the aerofoil and thickness of connecting arm are the most important factors on the power conversion coefficient of the vertical axis tidal current turbine.

  3. NMR ({sup 1}H and {sup 13}C) based signatures of abnormal choline metabolism in oral squamous cell carcinoma with no prominent Warburg effect

    SciTech Connect

    Bag, Swarnendu; Banerjee, Deb Ranjan; Basak, Amit; Das, Amit Kumar; Pal, Mousumi; Banerjee, Rita; Paul, Ranjan Rashmi; Chatterjee, Jyotirmoy

    2015-04-17

    At functional levels, besides genes and proteins, changes in metabolome profiles are instructive for a biological system in health and disease including malignancy. It is understood that metabolomic alterations in association with proteomic and transcriptomic aberrations are very fundamental to unravel malignant micro-ambient criticality and oral cancer is no exception. Hence deciphering intricate dimensions of oral cancer metabolism may be contributory both for integrated appreciation of its pathogenesis and to identify any critical but yet unexplored dimension of this malignancy with high mortality rate. Although several methods do exist, NMR provides higher analytical precision in identification of cancer metabolomic signature. Present study explored abnormal signatures in choline metabolism in oral squamous cell carcinoma (OSCC) using {sup 1}H and {sup 13}C NMR analysis of serum. It has demonstrated down-regulation of choline with concomitant up-regulation of its break-down product in the form of trimethylamine N-oxide in OSCC compared to normal counterpart. Further, no significant change in lactate profile in OSCC possibly indicated that well-known Warburg effect was not a prominent phenomenon in such malignancy. Amongst other important metabolites, malonate has shown up-regulation but D-glucose, saturated fatty acids, acetate and threonine did not show any significant change. Analyzing these metabolomic findings present study proposed trimethyl amine N-oxide and malonate as important metabolic signature for oral cancer with no prominent Warburg effect. - Highlights: • NMR ({sup 1}H and {sup 13}C) study of Oral Squamous cell Carcinoma Serum. • Abnormal Choline metabolomic signatures. • Up-regulation of Trimethylamine N-oxide. • Unchanged lactate profile indicates no prominent Warburg effect. • Proposed alternative glucose metabolism path through up-regulation of malonate.

  4. Anisotropy of the monomer random walk in a polymer melt: local-order and connectivity effects.

    PubMed

    Bernini, S; Leporini, D

    2016-05-11

    The random walk of a bonded monomer in a polymer melt is anisotropic due to local order and bond connectivity. We investigate both effects by molecular-dynamics simulations on melts of fully-flexible linear chains ranging from dimers (M  =  2) up to entangled polymers (M  =  200). The corresponding atomic liquid is also considered a reference system. To disentangle the influence of the local geometry and the bond arrangements, and to reveal their interplay, we define suitable measures of the anisotropy emphasising either the former or the latter aspect. Connectivity anisotropy, as measured by the correlation between the initial bond orientation and the direction of the subsequent monomer displacement, shows a slight enhancement due to the local order at times shorter than the structural relaxation time. At intermediate times-when the monomer displacement is comparable to the bond length-a pronounced peak and then decays slowly as t (-1/2), becoming negligible when the displacement is as large as about five bond lengths, i.e. about four monomer diameters or three Kuhn lengths. Local-geometry anisotropy, as measured by the correlation between the initial orientation of a characteristic axis of the Voronoi cell and the subsequent monomer dynamics, is affected at shorter times than the structural relaxation time by the cage shape with antagonistic disturbance by the connectivity. Differently, at longer times, the connectivity favours the persistence of the local-geometry anisotropy, which vanishes when the monomer displacement exceeds the bond length. Our results strongly suggest that the sole consideration of the local order is not enough to understand the microscopic origin of the rattling amplitude of the trapped monomer in the cage of the neighbours. PMID:27070080

  5. Effects of HIV and Combination Antiretroviral Therapy (cART) on Cortico-Striatal Functional Connectivity

    PubMed Central

    Ortega, Mario; Brier, Matthew R.; Ances, Beau M.

    2015-01-01

    Objective Determine whether HIV and cART affect resting state functional connectivity (rs-fc) between the striatum and cortical regions. Methods 49 HIV uninfected (HIV−) and 132 HIV infected (HIV+) (65% receiving combination anti-retroviral treatment [cART]) had laboratory studies (current and nadir CD4 T-cell counts, and plasma HIV viral load), neuropsychological performance (NP) testing, and neuroimaging. Rs-fc, which examines the coordination of neural activity in distant brain regions, was used to investigate cortico-striatal functional connections. The effect of cART was assessed comparing HIV+ individuals on cART (HIV+/cART+), and HIV+ individuals not currently receiving cART (HIV+/cART−). Relationships between laboratory tests, cognitive performance, and cART on subcortical-cortical rs-fc were assessed by an analysis of variance. Results HIV+ individuals had lower cortico-striatal functional connectivity than HIV− controls, specifically between the striatum and default mode network (DMN; p <0.001) and ventral attention network (VATT; p <0.001). HIV+/cART+ individuals had higher functional connectivity between the striatum and DMN (p=0.02) and VATT (p = 0.01) compared to HIV+/cART− subjects. Laboratory (current and nadir CD4 T-cell counts, plasma viral load) and NP were not correlated with cortico-striatal rs-fc. Conclusions HIV was associated with disrupted cortico-striatal networks, consistent with HIV’s known impact on subcortical areas. Interestingly, within certain networks HIV+/cART+ individuals had similar rs-fc compared to HIV− controls, suggesting possible improvements in HIV related neural dysfunction due to medications. Rs-fc may be a sensitive biomarker of neural insult and its recovery following cART. Additional studies may show rs-fc has utility in measuring acute inflammation caused by HIV. PMID:25849834

  6. Anisotropy of the monomer random walk in a polymer melt: local-order and connectivity effects

    NASA Astrophysics Data System (ADS)

    Bernini, S.; Leporini, D.

    2016-05-01

    The random walk of a bonded monomer in a polymer melt is anisotropic due to local order and bond connectivity. We investigate both effects by molecular-dynamics simulations on melts of fully-flexible linear chains ranging from dimers (M  =  2) up to entangled polymers (M  =  200). The corresponding atomic liquid is also considered a reference system. To disentangle the influence of the local geometry and the bond arrangements, and to reveal their interplay, we define suitable measures of the anisotropy emphasising either the former or the latter aspect. Connectivity anisotropy, as measured by the correlation between the initial bond orientation and the direction of the subsequent monomer displacement, shows a slight enhancement due to the local order at times shorter than the structural relaxation time. At intermediate times—when the monomer displacement is comparable to the bond length—a pronounced peak and then decays slowly as t ‑1/2, becoming negligible when the displacement is as large as about five bond lengths, i.e. about four monomer diameters or three Kuhn lengths. Local-geometry anisotropy, as measured by the correlation between the initial orientation of a characteristic axis of the Voronoi cell and the subsequent monomer dynamics, is affected at shorter times than the structural relaxation time by the cage shape with antagonistic disturbance by the connectivity. Differently, at longer times, the connectivity favours the persistence of the local-geometry anisotropy, which vanishes when the monomer displacement exceeds the bond length. Our results strongly suggest that the sole consideration of the local order is not enough to understand the microscopic origin of the rattling amplitude of the trapped monomer in the cage of the neighbours.

  7. Edge effects, not connectivity, determine the incidence and development of a foliar fungal plant disease.

    SciTech Connect

    Johnson, Brenda, L.; Haddad, Nick, M.

    2011-08-01

    Using a model plant-pathogen system in a large-scale habitat corridor experiment, we found that corridors do not facilitate the movement of wind-dispersed plant pathogens, that connectivity of patches does not enhance levels of foliar fungal plant disease, and that edge effects are the key drivers of plant disease dynamics. Increased spread of infectious disease is often cited as a potential negative effect of habitat corridors used in conservation, but the impacts of corridors on pathogen movement have never been tested empirically. Using sweet corn (Zea mays) and southern corn leaf blight (Cochliobolus heterostrophus) as a model plant-pathogen system, we tested the impacts of connectivity and habitat fragmentation on pathogen movement and disease development at the Savannah River Site, South Carolina, USA. Over time, less edgy patches had higher proportions of diseased plants, and distance of host plants to habitat edges was the greatest determinant of disease development. Variation in average daytime temperatures provided a possible mechanism for these disease patterns. Our results show that worries over the potentially harmful effects of conservation corridors on disease dynamics are misplaced, and that, in a conservation context, many diseases can be better managed by mitigating edge effects.

  8. GLIAL ABNORMALITIES IN MOOD DISORDERS

    PubMed Central

    Öngür, Dost; Bechtholt, Anita J.; Carlezon, William A.; Cohen, Bruce M.

    2015-01-01

    Multiple lines of evidence indicate that mood disorders are associated with abnormalities in the brain's cellular composition, especially in glial cells. Considered inert support cells in the past, glial cells are now known to be important for brain function. Treatments for mood disorders enhance glial cell proliferation, and experimental stimulation of cell growth has antidepressant effects in animal models of mood disorders. These findings suggest that the proliferation and survival of glial cells may be important in the pathogenesis of mood disorders and may be possible targets for the development of new treatments. In this chapter, we will review the evidence for glial abnormalities in mood disorders. We will discuss glial cell biology and evidence from postmortem studies of mood disorders. This is not carry out a comprehensive review; rather we selectively discuss existing evidence in building an argument for the role of glial cells in mood disorders. PMID:25377605

  9. Electron-energy loss study of nonlocal effects in connected plasmonic nanoprisms.

    PubMed

    Wiener, Aeneas; Duan, Huigao; Bosman, Michel; Horsfield, Andrew P; Pendry, John B; Yang, Joel K W; Maier, Stefan A; Fernández-Domínguez, Antonio I

    2013-07-23

    We investigate the emergence of nonlocal effects in plasmonic nanostructures through electron-energy loss spectroscopy. To theoretically describe the spatial dispersion in the metal permittivity, we develop a full three-dimensional nonlocal hydrodynamic solution of Maxwell's equations in frequency domain that implements the electron beam as a line current source. We use our numerical approach to perform an exhaustive analysis of the impact of nonlocality in the plasmonic response of single triangular prisms and connected bowtie dimers. Our results demonstrate the complexity of the interplay between nonlocal and geometric effects taking place in these structures. We show the different sensitivities to both effects of the various plasmonic modes supported by these systems. Finally, we present an experimental electron-energy loss study on gold nanoprisms connected by bridges as narrow as 1.6 nm. The comparison with our theoretical predictions enables us to reveal in a phenomenological fashion the enhancement of absorption damping that occurs in these atomistic junctions due to quantum confinement and grain boundary electron scattering. PMID:23782059

  10. Dosage effects of BDNF Val66Met polymorphism on cortical surface area and functional connectivity.

    PubMed

    Wang, Chao; Zhang, Yuanchao; Liu, Bing; Long, Haixia; Yu, Chunshui; Jiang, Tianzi

    2014-02-12

    The single nucleotide polymorphism (SNP) that leads to a valine-to-methionine substitution at codon 66 (Val66Met) in BDNF is correlated with differences in cognitive and memory functions, as well as with several neurological and psychiatric disorders. MRI studies have already shown that this genetic variant contributes to changes in cortical thickness and volume, but whether the Val66Met polymorphism affects the cortical surface area of healthy subjects remains unclear. Here, we used multimodal MRI to study whether this polymorphism would affect the cortical morphology and resting-state functional connectivity of a large sample of healthy Han Chinese human subjects. An SNP-wise general linear model analysis revealed a "dosage effect" of the Met allele, specifically a stepwise increase in cortical surface area of the right anterior insular cortex with increasing numbers of the Met allele. Moreover, we found enhanced functional connectivity between the anterior insular and the dorsolateral prefrontal cortices that was linked with the dosage of the Met allele. In conclusion, these data demonstrated a "dosage effect" of BDNF Val66Met on normal cortical structure and function, suggesting a new path for exploring the mechanisms underlying the effects of genotype on cognition. PMID:24523553

  11. Effectiveness of a regional corridor in connecting two Florida black bear populations.

    PubMed

    Dixon, Jeremy D; Oli, Madan K; Wooten, Michael C; Eason, Thomas H; McCown, J Walter; Paetkau, David

    2006-02-01

    Corridors may mitigate the adverse effects of habitat fragmentation by restoring or maintaining connectivity between disjunct populations. The efficacy of corridors for large carnivores, however has rarely been evaluated objectively. We used noninvasive sampling, microsatellite analysis, and population assignment tests to evaluate the effectiveness of a regional corridor in connecting two Florida black bear (Ursus americanus floridanus) populations (Osceola and Ocala). Bear movement was predominantly unidirectional, with a limited mixing of individuals from the two populations in one area of the corridor We also documented bears in Osceola that were genetically assigned to Ocala and bears in Osceola that may be offspring from an Osceola-Ocala mating. Our results indicate that the Osceola-Ocala corridor is functional and provides a conduit for gene flow between these populations. Human development, however may hinder the use of the Osceola-Ocala corridor by bears. The noninvasive sampling and genetic methods we used provide a means of evaluating corridor effectiveness that can help identify linkages necessary for maintaining metapopulation structure and population viability. PMID:16909668

  12. Altered resting state functional network connectivity in children absence epilepsy.

    PubMed

    Li, Qifu; Cao, Weifang; Liao, Xiaoping; Chen, Zhibin; Yang, Tianhua; Gong, Qiyong; Zhou, Dong; Luo, Cheng; Yao, Dezhong

    2015-07-15

    Altered functional connectivity has been associated with the influence of epileptic activity. Abnormalities in connectivity, particularly in dorsal attention (DAN), salience (SN) and default mode (DMN) networks, might contribute to the loss of consciousness during seizures and cognitive deficits in patients with children absence epilepsy (CAE). The objective of the present study was to identify whether the functional network connectivity (FNC) is changed between patients with CAE and healthy controls. Using independent component analysis, twelve resting state networks (RSNs) were identified in resting state functional magnetic resonance imaging data sets in eighteen CAE patients and twenty-one healthy controls. Analyses of the group differences in FNC strength were conducted, controlling for age and gender effects. The findings showed that some functional networks were clustered into two subgroups, correlated within subgroups and antagonized with each other. Compared with the controls, patients with CAE demonstrated abnormal FNC strength among three networks: DMN, DAN and SN. In addition, the antagonism of two subgroups was altered. These results might reflect the underlying neuronal functional impairment or altered integration among these RSNs in CAE, suggesting that the abnormal functional connectivity is likely to imply the pathological mechanism associated with the accumulative influence of epileptic activity. These findings contribute to the understanding of the behavior abnormality in CAE, such as disturbed executive and attentional functions and the loss of consciousness during absence seizures. PMID:25982500

  13. 26 CFR 1.864-4 - U.S. source income effectively connected with U.S. business.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... that 26 CFR 1.864-4 (c)(5)(iii) as it appeared in the Code of Federal Regulations revised as of April 1... 26 Internal Revenue 9 2014-04-01 2014-04-01 false U.S. source income effectively connected with U... Years Prior to December 30, 1996 § 1.864-4 U.S. source income effectively connected with U.S....

  14. 26 CFR 1.864-4 - U.S. source income effectively connected with U.S. business.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... that 26 CFR 1.864-4 (c)(5)(iii) as it appeared in the Code of Federal Regulations revised as of April 1... 26 Internal Revenue 9 2012-04-01 2012-04-01 false U.S. source income effectively connected with U... Years Prior to December 30, 1996 § 1.864-4 U.S. source income effectively connected with U.S....

  15. 26 CFR 1.864-4 - U.S. source income effectively connected with U.S. business.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... that 26 CFR 1.864-4 (c)(5)(iii) as it appeared in the Code of Federal Regulations revised as of April 1... 26 Internal Revenue 9 2013-04-01 2013-04-01 false U.S. source income effectively connected with U... Years Prior to December 30, 1996 § 1.864-4 U.S. source income effectively connected with U.S....

  16. 26 CFR 1.864-4 - U.S. source income effectively connected with U.S. business.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... that 26 CFR 1.864-4 (c)(5)(iii) as it appeared in the Code of Federal Regulations revised as of April 1... 26 Internal Revenue 9 2011-04-01 2011-04-01 false U.S. source income effectively connected with U... Years Prior to December 30, 1996 § 1.864-4 U.S. source income effectively connected with U.S....

  17. HERMES: towards an integrated toolbox to characterize functional and effective brain connectivity.

    PubMed

    Niso, Guiomar; Bruña, Ricardo; Pereda, Ernesto; Gutiérrez, Ricardo; Bajo, Ricardo; Maestú, Fernando; del-Pozo, Francisco

    2013-10-01

    The analysis of the interdependence between time series has become an important field of research in the last years, mainly as a result of advances in the characterization of dynamical systems from the signals they produce, the introduction of concepts such as generalized and phase synchronization and the application of information theory to time series analysis. In neurophysiology, different analytical tools stemming from these concepts have added to the 'traditional' set of linear methods, which includes the cross-correlation and the coherency function in the time and frequency domain, respectively, or more elaborated tools such as Granger Causality.This increase in the number of approaches to tackle the existence of functional (FC) or effective connectivity (EC) between two (or among many) neural networks, along with the mathematical complexity of the corresponding time series analysis tools, makes it desirable to arrange them into a unified-easy-to-use software package. The goal is to allow neuroscientists, neurophysiologists and researchers from related fields to easily access and make use of these analysis methods from a single integrated toolbox.Here we present HERMES ( http://hermes.ctb.upm.es ), a toolbox for the Matlab® environment (The Mathworks, Inc), which is designed to study functional and effective brain connectivity from neurophysiological data such as multivariate EEG and/or MEG records. It includes also visualization tools and statistical methods to address the problem of multiple comparisons. We believe that this toolbox will be very helpful to all the researchers working in the emerging field of brain connectivity analysis. PMID:23812847

  18. The Potential Connectivity of Waterhole Networks and the Effectiveness of a Protected Area under Various Drought Scenarios

    PubMed Central

    O’Farrill, Georgina; Gauthier Schampaert, Kim; Rayfield, Bronwyn; Bodin, Örjan; Calmé, Sophie; Sengupta, Raja; Gonzalez, Andrew

    2014-01-01

    Landscape connectivity is considered a priority for ecosystem conservation because it may mitigate the synergistic effects of climate change and habitat loss. Climate change predictions suggest changes in precipitation regimes, which will affect the availability of water resources, with potential consequences for landscape connectivity. The Greater Calakmul Region of the Yucatan Peninsula (Mexico) has experienced a 16% decrease in precipitation over the last 50 years, which we hypothesise has affected water resource connectivity. We used a network model of connectivity, for three large endangered species (Baird’s tapir, white-lipped peccary and jaguar), to assess the effect of drought on waterhole availability and connectivity in a forested landscape inside and adjacent to the Calakmul Biosphere Reserve. We used reported travel distances and home ranges for our species to establish movement distances in our model. Specifically, we compared the effects of 10 drought scenarios on the number of waterholes (nodes) and the subsequent changes in network structure and node importance. Our analysis revealed that drought dramatically influenced spatial structure and potential connectivity of the network. Our results show that waterhole connectivity and suitable habitat (area surrounding waterholes) is lost faster inside than outside the reserve for all three study species, an outcome that may drive them outside the reserve boundaries. These results emphasize the need to assess how the variability in the availability of seasonal water resource may affect the viability of animal populations under current climate change inside and outside protected areas. PMID:24830392

  19. The potential connectivity of waterhole networks and the effectiveness of a protected area under various drought scenarios.

    PubMed

    O'Farrill, Georgina; Gauthier Schampaert, Kim; Rayfield, Bronwyn; Bodin, Örjan; Calmé, Sophie; Sengupta, Raja; Gonzalez, Andrew

    2014-01-01

    Landscape connectivity is considered a priority for ecosystem conservation because it may mitigate the synergistic effects of climate change and habitat loss. Climate change predictions suggest changes in precipitation regimes, which will affect the availability of water resources, with potential consequences for landscape connectivity. The Greater Calakmul Region of the Yucatan Peninsula (Mexico) has experienced a 16% decrease in precipitation over the last 50 years, which we hypothesise has affected water resource connectivity. We used a network model of connectivity, for three large endangered species (Baird's tapir, white-lipped peccary and jaguar), to assess the effect of drought on waterhole availability and connectivity in a forested landscape inside and adjacent to the Calakmul Biosphere Reserve. We used reported travel distances and home ranges for our species to establish movement distances in our model. Specifically, we compared the effects of 10 drought scenarios on the number of waterholes (nodes) and the subsequent changes in network structure and node importance. Our analysis revealed that drought dramatically influenced spatial structure and potential connectivity of the network. Our results show that waterhole connectivity and suitable habitat (area surrounding waterholes) is lost faster inside than outside the reserve for all three study species, an outcome that may drive them outside the reserve boundaries. These results emphasize the need to assess how the variability in the availability of seasonal water resource may affect the viability of animal populations under current climate change inside and outside protected areas. PMID:24830392

  20. Cost-Effectiveness of Global Endometrial Ablation vs. Hysterectomy for Treatment of Abnormal Uterine Bleeding: US Commercial and Medicaid Payer Perspectives

    PubMed Central

    Lenhart, Gregory M.; Bonafede, Machaon M.; Lukes, Andrea S.; Laughlin-Tommaso, Shannon K.

    2015-01-01

    Abstract Cost-effectiveness modeling studies of global endometrial ablation (GEA) for treatment of abnormal uterine bleeding (AUB) from a US perspective are lacking. The objective of this study was to model the cost-effectiveness of GEA vs. hysterectomy for treatment of AUB in the United States from both commercial and Medicaid payer perspectives. The study team developed a 1-, 3-, and 5-year semi-Markov decision-analytic model to simulate 2 hypothetical patient cohorts of women with AUB—1 treated with GEA and the other with hysterectomy. Clinical and economic data (including treatment patterns, health care resource utilization, direct costs, and productivity costs) came from analyses of commercial and Medicaid claims databases. Analysis results show that cost savings with simultaneous reduction in treatment complications and fewer days lost from work are achieved with GEA versus hysterectomy over almost all time horizons and under both the commercial payer and Medicaid perspectives. Cost-effectiveness metrics also favor GEA over hysterectomy from both the commercial payer and Medicaid payer perspectives—evidence strongly supporting the clinical-economic value about GEA versus hysterectomy. Results will interest clinicians, health care payers, and self-insured employers striving for cost-effective AUB treatments. (Population Health Management 2015;18:373–382) PMID:25714906

  1. Altered periaqueductal gray resting state functional connectivity in migraine and the modulation effect of treatment.

    PubMed

    Li, Zhengjie; Liu, Mailan; Lan, Lei; Zeng, Fang; Makris, Nikos; Liang, Yilin; Guo, Taipin; Wu, Feng; Gao, Yujie; Dong, Mingkai; Yang, Jie; Li, Ying; Gong, Qiyong; Liang, Fanrong; Kong, Jian

    2016-01-01

    The aims of this study were to 1) compare resting state functional connectivity (rs-fc) of the periaqueductal gray (PAG), a key region in the descending pain modulatory system (DPMS) between migraine without aura (MwoA) patients and healthy controls (HC), and 2) investigate how an effective treatment can influence the PAG rs-fc in MwoA patients. One hundred MwoA patients and forty-six matched HC were recruited. Patients were randomized to verum acupuncture, sham acupuncture, and waiting list groups. Resting state fMRI data were collected and seed based functional connectivity analysis was applied. Compared with HC, MwoA patients showed reduced rs-fc between the PAG and rostral anterior cingulate cortex/medial prefrontal cortex (rACC/mPFC), key regions in the DPMS and other pain related brain regions. The reduced rs-fc between the PAG and rACC/mPFC was associated with increased migraine headache intensity at the baseline. After treatments, rs-fc between the PAG and the rACC in MwoA patients significantly increased. The changes of rs-fc among the PAG, rACC and ventral striatum were significantly associated with headache intensity improvement. Impairment of the DPMS is involved in the neural pathophysiology of migraines. Impaired DPMS in migraine patients can be normalized after effective treatment. PMID:26839078

  2. Shifts of Effective Connectivity within a Language Network during Rhyming and Spelling

    PubMed Central

    Bitan, Tali; Booth, James R.; Choy, Janet; Burman, Douglas D.; Gitelman, Darren R.; Mesulam, M.-Marsel

    2005-01-01

    We used functional magnetic resonance imaging to examine task-specific modulations of effective connectivity within a left-hemisphere language network during spelling and rhyming judgments on visually presented words. We identified sites showing task-specific activations for rhyming in the lateral temporal cortex (LTC) and for spelling in the intraparietal sulcus (IPS). The inferior frontal gyrus (IFG) and fusiform gyrus were engaged by both tasks. Dynamic causal modeling showed that each task preferentially strengthened modulatory influences converging on its task-specific site (LTC for rhyming, IPS for spelling). These remarkably selective and symmetrical findings demonstrate that the nature of the behavioral task dynamically shifts the locus of integration (or convergence) to the network component specialized for that task. Furthermore, they suggest that the role of the task-selective areas is to provide a differential synthesis of incoming information rather than providing differential control signals influencing the activity of other network components. Our findings also showed that switching tasks led to changes in the target area influenced by the IFG, suggesting that the IFG may play a pivotal role in setting the cognitive context for each task. We propose that task-dependent shifts in effective connectivity are likely to be mediated through top-down modulations from the IFG to the task-selective regions in a way that differentially enhances their sensitivity to incoming word-form information. PMID:15930389

  3. Altered periaqueductal gray resting state functional connectivity in migraine and the modulation effect of treatment

    PubMed Central

    Li, Zhengjie; Liu, Mailan; Lan, Lei; Zeng, Fang; Makris, Nikos; Liang, Yilin; Guo, Taipin; Wu, Feng; Gao, Yujie; Dong, Mingkai; Yang, Jie; Li, Ying; Gong, Qiyong; Liang, Fanrong; Kong, Jian

    2016-01-01

    The aims of this study were to 1) compare resting state functional connectivity (rs-fc) of the periaqueductal gray (PAG), a key region in the descending pain modulatory system (DPMS) between migraine without aura (MwoA) patients and healthy controls (HC), and 2) investigate how an effective treatment can influence the PAG rs-fc in MwoA patients. One hundred MwoA patients and forty-six matched HC were recruited. Patients were randomized to verum acupuncture, sham acupuncture, and waiting list groups. Resting state fMRI data were collected and seed based functional connectivity analysis was applied. Compared with HC, MwoA patients showed reduced rs-fc between the PAG and rostral anterior cingulate cortex/medial prefrontal cortex (rACC/mPFC), key regions in the DPMS and other pain related brain regions. The reduced rs-fc between the PAG and rACC/mPFC was associated with increased migraine headache intensity at the baseline. After treatments, rs-fc between the PAG and the rACC in MwoA patients significantly increased. The changes of rs-fc among the PAG, rACC and ventral striatum were significantly associated with headache intensity improvement. Impairment of the DPMS is involved in the neural pathophysiology of migraines. Impaired DPMS in migraine patients can be normalized after effective treatment. PMID:26839078

  4. Neuroticism and extraversion moderate neural responses and effective connectivity during appetitive conditioning.

    PubMed

    Schweckendiek, Jan; Stark, Rudolf; Klucken, Tim

    2016-08-01

    Classical appetitive conditioning constitutes a basic learning process through which environmental stimuli can be associated with reward. Previous studies showed that individual differences in neuroticism and extraversion influence emotional processing and have been shown to modulate neural activity in subcortical and prefrontal areas in response to emotional stimuli. However, the role of individual differences in appetitive conditioning has so far not been investigated in detail. The aim of this study was to assess the association between neuroticism and extraversion with neural activity and connectivity during appetitive conditioning. The conditioned stimulus (CS) was either a picture of a dish or a cup. One stimulus (CS+) was paired with a monetary reward and the other stimulus (CS-) was associated with its absence while hemodynamic activity was measured by means of functional magnetic resonance imaging. A significant negative correlation of neuroticism scores with amygdala activity was observed during appetitive conditioning. Further, extraversion was positively associated with responses in the hippocampus and the thalamus. In addition, effective connectivity between the amygdala as a seed region and the anterior cingulate cortex, the insula, and the thalamus was negatively correlated with neuroticism scores and positively correlated with extraversion scores. The results may indicate a neural correlate for the deficits in appetitive learning in subjects with high neuroticism scores and point to a facilitating effect of extraversion on reward-related learning. Hum Brain Mapp 37:2992-3002, 2016. © 2016 Wiley Periodicals, Inc. PMID:27132706

  5. Effects of a lifestyle modification trial among phenotypically obese metabolically normal and phenotypically obese metabolically abnormal adolescents in comparison with phenotypically normal metabolically obese adolescents.

    PubMed

    Kelishadi, Roya; Hashemipour, Mahin; Sarrafzadegan, Nizal; Mohammadifard, Noushin; Alikhasy, Hasan; Beizaei, Maryam; Sajjadi, Firouzeh; Poursafa, Parinaz; Amin, Zahra; Ghatreh-Samani, Shohreh; Khavarian, Noushin; Siadat, Zahra Dana

    2010-07-01

    This study aimed to assess the effects of a 2-month lifestyle modification trial on cardio-metabolic abnormalities and C-reactive protein (CRP) among obese adolescents with metabolic syndrome [phenotypically obese metabolically abnormal (POMA)] and obese adolescents without a cardio-metabolic disorder [phenotypically obese metabolically normal (POMN)], as well as in normal-weight adolescents with at least one cardio-metabolic disorder [phenotypically normal metabolically obese (PNMO)]. The study comprised 360 adolescents assigned in three groups of equal number of POMN, POMA and PNMO. They were enrolled in a trial consisting of aerobic activity classes, diet and behaviour modification, and were recalled after 6 months. Overall, 94.7% of participants completed the 2-month trial, and 87.3% of them returned after 6 months. The mean CRP was not significantly different between the POMA and PNMO groups, but was higher than in the POMN group. After the trial, body mass index (BMI) and waist circumference (WC) decreased in obese participants, and the mean body fat mass decreased in all groups. At 2 months, the mean total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), triglycerides (TG) and CRP decreased in the POMA and PNMO groups. After 2 and 6 months, the decrease in mean TC, LDL-C, TG, CRP and systolic blood pressure was greater in the POMA than in the POMN group. The magnitude of decrease in CRP correlated with that of BMI, WC, fat mass, TG, TC and LDL-C. Lifestyle modification programmes for primordial/primary prevention of chronic diseases would be beneficial at the population level and should not be limited to obese children. PMID:20929499

  6. Changes in functional connectivity related to direct training and generalization effects of a word finding treatment in chronic aphasia.

    PubMed

    Sandberg, Chaleece W; Bohland, Jason W; Kiran, Swathi

    2015-11-01

    The neural mechanisms that underlie generalization of treatment-induced improvements in word finding in persons with aphasia (PWA) are currently poorly understood. This study aimed to shed light on changes in functional network connectivity underlying generalization in aphasia. To this end, we used fMRI and graph theoretic analyses to examine changes in functional connectivity after a theoretically-based word-finding treatment in which abstract words were used as training items with the goal of promoting generalization to concrete words. Ten right-handed native English-speaking PWA (7 male, 3 female) ranging in age from 47 to 75 (mean=59) participated in this study. Direct training effects coincided with increased functional connectivity for regions involved in abstract word processing. Generalization effects coincided with increased functional connectivity for regions involved in concrete word processing. Importantly, similarities between training and generalization effects were noted as were differences between participants who generalized and those who did not. PMID:26398158

  7. Abnormal response to stress and impaired NPS-induced hyperlocomotion, anxiolytic effect and corticosterone increase in mice lacking NPSR1.

    PubMed

    Zhu, Hongyan; Mingler, Melissa K; McBride, Melissa L; Murphy, Andrew J; Valenzuela, David M; Yancopoulos, George D; Williams, Michael T; Vorhees, Charles V; Rothenberg, Marc E

    2010-09-01

    NPSR1 is a G protein coupled receptor expressed in multiple brain regions involved in modulation of stress. Central administration of NPS, the putative endogenous ligand of NPSR1, can induce hyperlocomotion, anxiolytic effects and activation of the HPA axis. The role of NPSR1 in the brain remains unsettled. Here we used NPSR1 gene-targeted mice to define the functional role of NPSR1 under basal conditions on locomotion, anxiety- and/or depression-like behavior, corticosterone levels, acoustic startle with prepulse inhibition, learning and memory, and under NPS-induced locomotor activation, anxiolysis, and corticosterone release. Male, but not female, NPSR1-deficient mice exhibited enhanced depression-like behavior in a forced swim test, reduced acoustic startle response, and minor changes in the Morris water maze. Neither male nor female NPSR1-deficient mice showed alterations of baseline locomotion, anxiety-like behavior, or corticosterone release after exposure to a forced swim test or methamphetamine challenge in an open-field. After intracerebroventricular (ICV) administration of NPS, NPSR1-deficient mice failed to show normal NPS-induced increases in locomotion, anxiolysis, or corticosterone release compared with WT NPS-treated mice. These findings demonstrate that NPSR1 is essential in mediating NPS effects on behavior. PMID:20171785

  8. Abnormal response to stress and impaired NPS-induced hyperlocomotion, anxiolytic effect and corticosterone increase in mice lacking NPSR1

    PubMed Central

    Zhu, Hongyan; Mingler, Melissa K.; McBride, Melissa L.; Murphy, Andrew J.; Valenzuela, David M.; Yancopoulos, George D.; Williams, Michael T.; Vorhees, Charles V.; Rothenberg, Marc E.

    2010-01-01

    Summary NPSR1 is a G protein coupled receptor expressed in multiple brain regions involved in modulation of stress. Central administration of NPS, the putative endogenous ligand of NPSR1, can induce hyperlocomotion, anxiolytic effects and activation of the HPA axis. The role of NPSR1 in the brain remains unsettled. Here we used NPSR1 gene-targeted mice to define the functional role of NPSR1 under basal conditions on locomotion, anxiety- and/or depression-like behavior, corticosterone levels, acoustic startle with prepulse inhibition, learning and memory, and under NPS-induced locomotor activation, anxiolysis, and corticosterone release. Male, but not female, NPSR1-deficient mice exhibited enhanced depression-like behavior in a forced swim test, reduced acoustic startle response, and minor changes in the Morris water maze. Neither male nor female NPSR1-deficient mice showed alterations of baseline locomotion, anxiety-like behavior, or corticosterone release after exposure to a forced swim test or methamphetamine challenge in an open-field. After intracerebroventricular (ICV) administration of NPS, NPSR1-deficient mice failed to show normal NPS-induced increases in locomotion, anxiolysis, or corticosterone release compared with WT NPS-treated mice. These findings demonstrate that NPSR1 is essential in mediating NPS effects on behavior. PMID:20171785

  9. Effects of Abnormal Savda Munzip on the Proliferation Activity and Migration Ability of Fibroblasts Derived from Hypertrophic Scar In Vitro

    PubMed Central

    Wang, Hujun; Gao, Weicheng; Kong, Menglong; Li, Nan; Shaolin, Ma

    2015-01-01

    Background. To explore the effect of ASMq on proliferation and migration ability of the fibroblast derived from HS of donor (HSFbs) in vitro. Methods. The HSFbs were cultured from tissue specimens and passaged to the 3~4 generation, which were treated with the different concentrations of ASMq and 5-Fu from 1 to 11 days. The difference of HSFbs proliferation activity was analyzed by the CCK-8 method. The HSFbs migration ability in ASMq (0.4 mg/mL) was analyzed by the Cell Scratch method. Results. Transmission electron microscope result shows ASMq concentration significantly increases and fibroblast cell structure markedly change in the experimental group. The proliferation activity of the HSFbs was obviously weakened in ASMq groups than those of the group A (P < 0.05) at seven days. The group C (0.4 mg/mL) is better suitable than other three ASMq treatment groups. Cell Migration Assay shows that the migration ability HSFbs was significantly reduced in ASMq (0.4 mg/mL) treatment group compared with those of blank control group at both 24 h and 48 h (P < 0.05). Conclusions. These results suggest that ASMq effectively restrains the proliferation and migration ability of the HTSFbs in vitro, which can be one of the mechanisms for the prevention and treatment of HS. PMID:25821502

  10. An Index of Longitudinal Hydrologic Connectivity to Evaluate Effects of Water Abstraction on Streams Dominated by Migratory Shrimps

    NASA Astrophysics Data System (ADS)

    Crook, K. E.; Pringle, C. M.; Freeman, M. C.; Scatena, F. N.

    2005-05-01

    Massive water withdrawals from streams draining the Caribbean National Forest (CNF), Puerto Rico, are threatening their biotic integrity. Migratory tropical shrimps are ideal indicator species to measure water withdrawal effects on riverine connectivity and biointegrity because: (1) their migratory range encompasses the stream network from estuaries to headwater streams; (2) they represent greater than 90% of biomass in streams draining the CNF; and (3) they facilitate important in-stream ecological processes. We developed an index to evaluate individual and cumulative effects of water intakes on each stage of the shrimp's life-cycle. Effect of water withdrawal on longitudinal connectivity was evaluated by combining effects of water withdrawal on larval and juvenile shrimps. Larvae require downstream transport to the estuary for advancement to the next life-stage, and juveniles similarly require access to headwater streams. Therefore, these two life-stages represent the bi-directional connectivity of streams from headwaters to estuaries. Seventeen water intakes were evaluated in and around the CNF. Larger intakes cause a greater decrease in connectivity than smaller intakes; however, several small, high elevation intakes had very low connectivity. Also, intakes with alternative designs, such as a French drain, have reduced effects on connectivity.

  11. Abnormal Behavior in Relation to Cage Size in Rhesus Monkeys

    ERIC Educational Resources Information Center

    Paulk, H. H.; And Others

    1977-01-01

    Examines the effects of cage size on stereotyped and normal locomotion and on other abnormal behaviors in singly caged animals, whether observed abnormal behaviors tend to co-occur, and if the development of an abnormal behavior repertoire leads to reduction in the number of normal behavior categories. (Author/RK)

  12. Protective effect of oleanolic acid on oxidative injury and cellular abnormalities in doxorubicin induced cardiac toxicity in rats.

    PubMed

    Goyal, Sameer N; Mahajan, Umesh B; Chandrayan, Govind; Kumawat, Vivek S; Kamble, Sarika; Patil, Pradip; Agrawal, Yogeeta O; Patil, Chandragouda R; Ojha, Shreesh

    2016-01-01

    The prevention of doxorubicin (Dox) induced cardiotoxicity may be co-operative to recover future Dox treatment. The aim of this study was to explore the cardioprotective effects of oleanolic acid (OA), an antioxidant agent, on Dox induced cardiotoxicity. OA is a triterpenoid compound, which exist widely in plant kingdom in free acid form or as a glycosidic triterpenoids saponins. Cardiotoxicity was induced in Wistar rats with single intravenous injection of doxorubicin at dose of 67.75 mg/kg i.v for 48 hrs. At 12 hrs of interval following Dox administration the cardioprotective effect of OA (1.5 mg/kg, i.v.) and Amifostine (AMF) (90 mg/kg i.v., single dose prior 30 min) were evaluated. Induction of cardiotoxicity was confirmed by increase in systolic, diastolic, mean arterial pressures, maximal positive rate of developed left ventricular pressure (+LVdP/dtmax, an indicator of myocardial contraction), maximal negative rate of developed left ventricular pressure (-LVdP/dtmax, a meter of myocardial relaxation) and an increase in left ventricular end-diastolic pressure (LVEDP, a marker of pre-load). Cardiac markers in such as CK-MB, LDH and alterations in ECG. Dox administration showed alteration in Biochemical parameters and endogenous antioxidants. Administration of OA Showed maximal protection against Dox induced cardiac toxicity as observed by reduction in blood pressure, prevention of left ventricular function and attenuation of biochemical and antioxidant parameters. Based on the findings, its concluded that OA can be used as an adjuvant with Dox therapy in treating cancers. PMID:27069540

  13. Protective effect of oleanolic acid on oxidative injury and cellular abnormalities in doxorubicin induced cardiac toxicity in rats

    PubMed Central

    Goyal, Sameer N; Mahajan, Umesh B; Chandrayan, Govind; Kumawat, Vivek S; Kamble, Sarika; Patil, Pradip; Agrawal, Yogeeta O; Patil, Chandragouda R; Ojha, Shreesh

    2016-01-01

    The prevention of doxorubicin (Dox) induced cardiotoxicity may be co-operative to recover future Dox treatment. The aim of this study was to explore the cardioprotective effects of oleanolic acid (OA), an antioxidant agent, on Dox induced cardiotoxicity. OA is a triterpenoid compound, which exist widely in plant kingdom in free acid form or as a glycosidic triterpenoids saponins. Cardiotoxicity was induced in Wistar rats with single intravenous injection of doxorubicin at dose of 67.75 mg/kg i.v for 48 hrs. At 12 hrs of interval following Dox administration the cardioprotective effect of OA (1.5 mg/kg, i.v.) and Amifostine (AMF) (90 mg/kg i.v., single dose prior 30 min) were evaluated. Induction of cardiotoxicity was confirmed by increase in systolic, diastolic, mean arterial pressures, maximal positive rate of developed left ventricular pressure (+LVdP/dtmax, an indicator of myocardial contraction), maximal negative rate of developed left ventricular pressure (-LVdP/dtmax, a meter of myocardial relaxation) and an increase in left ventricular end-diastolic pressure (LVEDP, a marker of pre-load). Cardiac markers in such as CK-MB, LDH and alterations in ECG. Dox administration showed alteration in Biochemical parameters and endogenous antioxidants. Administration of OA Showed maximal protection against Dox induced cardiac toxicity as observed by reduction in blood pressure, prevention of left ventricular function and attenuation of biochemical and antioxidant parameters. Based on the findings, its concluded that OA can be used as an adjuvant with Dox therapy in treating cancers. PMID:27069540

  14. Modeling the effective connectivity of the visual network in healthy and photosensitive, epileptic baboons.

    PubMed

    Ákos Szabó, C; Salinas, Felipe S; Li, Karl; Franklin, Crystal; Leland, M Michelle; Fox, Peter T; Laird, Angela R; Narayana, Shalini

    2016-05-01

    The baboon provides a model of photosensitive, generalized epilepsy. This study compares cerebral blood flow responses during intermittent light stimulation (ILS) between photosensitive (PS) and healthy control (CTL) baboons using H 2 (15) O-PET. We examined effective connectivity associated with visual stimulation in both groups using structural equation modeling (SEM). Eight PS and six CTL baboons, matched for age, gender and weight, were classified on the basis of scalp EEG findings performed during the neuroimaging studies. Five H 2 (15) O-PET studies were acquired alternating between resting and activation (ILS at 25 Hz) scans. PET images were acquired in 3D mode and co-registered with MRI. SEM demonstrated differences in neural connectivity between PS and CTL groups during ILS that were not previously identified using traditional activation analyses. First-level pathways consisted of similar posterior-to-anterior projections in both groups. While second-level pathways were mainly lateralized to the left hemisphere in the CTL group, they consisted of bilateral anterior-to-posterior projections in the PS baboons. Third- and fourth-level pathways were only evident in PS baboons. This is the first functional neuroimaging study used to model the photoparoxysmal response (PPR) using a primate model of photosensitive, generalized epilepsy. Evidence of increased interhemispheric connectivity and bidirectional feedback loops in the PS baboons represents electrophysiological synchronization associated with the generation of epileptic discharges. PS baboons demonstrated decreased model stability compared to controls, which may be attributed to greater variability in the driving response or PPRs, or to the influence of regions not included in the model. PMID:25749860

  15. Cognitive control and the salience network: an investigation of error processing and effective connectivity.

    PubMed

    Ham, Timothy; Leff, Alex; de Boissezon, Xavier; Joffe, Anna; Sharp, David J

    2013-04-17

    The Salience Network (SN) consists of the dorsal anterior cingulate cortex (dACC) and bilateral insulae. The network responds to behaviorally salient events, and an important question is how its nodes interact. One theory is that the dACC provides the earliest cortical signal of behaviorally salient events, such as errors. Alternatively, the anterior right insula (aRI) has been proposed to provide an early cognitive control signal. As these regions frequently coactivate, it has been difficult to disentangle their roles using conventional methods. Here we use dynamic causal modeling and a Bayesian model evidence technique to investigate the causal relationships between nodes in the SN after errors. Thirty-five human subjects performed the Simon task. The task has two conditions (congruent and incongruent) producing two distinct error types. Neural activity associated with errors was investigated using fMRI. Subjects made a total of 1319 congruent and 1617 incongruent errors. Errors resulted in robust activation of the SN. Dynamic causal modeling analyses demonstrated that input into the SN was most likely via the aRI for both error types and that the aRI was the only region intrinsically connected to both other nodes. Only incongruent errors produced behavioral adaptation, and the strength of the connection between the dACC and the left insulae correlated with the extent of this behavioral change. We conclude that the aRI, not the dACC, drives the SN after errors on an attentionally demanding task, and that a change in the effective connectivity of the dACC is associated with behavioral adaptation after errors. PMID:23595766

  16. Formal relations connecting different approaches to calculate relativistic effects on molecular magnetic properties

    NASA Astrophysics Data System (ADS)

    Zaccari, D. G.; Ruiz de Azúa, M. C.; Melo, J. I.; Giribet, C. G.

    2006-02-01

    In the present work a set of formal relations connecting different approaches to calculate relativistic effects on magnetic molecular properties are proven. The linear response (LR) within the elimination of the small component (ESC), Breit Pauli, and minimal-coupling approaches are compared. To this end, the leading order ESC reduction of operators within the minimal-coupling four-component approach is carried out. The equivalence of all three approaches within the ESC approximation is proven. It is numerically verified for the NMR nuclear-magnetic shielding tensor taking HX and CH3X (X =Br,I) as model compounds. Formal relations proving the gauge origin invariance of the full relativistic effect on the NMR nuclear-magnetic shielding tensor within the LR-ESC approach are presented.

  17. Morphological abnormalities in elasmobranchs.

    PubMed

    Moore, A B M

    2015-08-01

    A total of 10 abnormal free-swimming (i.e., post-birth) elasmobranchs are reported from The (Persian-Arabian) Gulf, encompassing five species and including deformed heads, snouts, caudal fins and claspers. The complete absence of pelvic fins in a milk shark Rhizoprionodon acutus may be the first record in any elasmobranch. Possible causes, including the extreme environmental conditions and the high level of anthropogenic pollution particular to The Gulf, are briefly discussed. PMID:25903257

  18. College Connection

    ERIC Educational Resources Information Center

    Hewitt, Kimberly Kappler; Scalzo, Mary Jo

    2012-01-01

    This article describes Oakwood City School District's College Connection Study, which is now in its eighth year. The purpose of the study is to help the educators in the district learn how to effectively prepare students for success in the colleges of their choice. Teachers, administrators, and other staff members travel to colleges to conduct…

  19. Effects of Land Use on Lake Nutrients: The Importance of Scale, Hydrologic Connectivity, and Region.

    PubMed

    Soranno, Patricia A; Cheruvelil, Kendra Spence; Wagner, Tyler; Webster, Katherine E; Bremigan, Mary Tate

    2015-01-01

    Catchment land uses, particularly agriculture and urban uses, have long been recognized as major drivers of nutrient concentrations in surface waters. However, few simple models have been developed that relate the amount of catchment land use to downstream freshwater nutrients. Nor are existing models applicable to large numbers of freshwaters across broad spatial extents such as regions or continents. This research aims to increase model performance by exploring three factors that affect the relationship between land use and downstream nutrients in freshwater: the spatial extent for measuring land use, hydrologic connectivity, and the regional differences in both the amount of nutrients and effects of land use on them. We quantified the effects of these three factors that relate land use to lake total phosphorus (TP) and total nitrogen (TN) in 346 north temperate lakes in 7 regions in Michigan, USA. We used a linear mixed modeling framework to examine the importance of spatial extent, lake hydrologic class, and region on models with individual lake nutrients as the response variable, and individual land use types as the predictor variables. Our modeling approach was chosen to avoid problems of multi-collinearity among predictor variables and a lack of independence of lakes within regions, both of which are common problems in broad-scale analyses of freshwaters. We found that all three factors influence land use-lake nutrient relationships. The strongest evidence was for the effect of lake hydrologic connectivity, followed by region, and finally, the spatial extent of land use measurements. Incorporating these three factors into relatively simple models of land use effects on lake nutrients should help to improve predictions and understanding of land use-lake nutrient interactions at broad scales. PMID:26267813

  20. Effective brain connectivity in children with reading difficulties during phonological processing

    PubMed Central

    Cao, Fan; Bitan, Tali; Booth, James R.

    2009-01-01

    Using Dynamic Causal Modeling (DCM) and functional magnetic resonance imaging (fMRI), we examined effective connectivity between three left hemisphere brain regions (inferior frontal gyrus, inferior parietal lobule, fusiform gyrus) and bilateral medial frontal gyrus in 12 children with reading difficulties (M age = 12.4, range: 8.11–14.10) and 12 control children (M age = 12.3, range: 8.9–14.11) during rhyming judgments to visually presented words. More difficult conflicting trials either had similar orthography but different phonology (e.g. pint-mint) or similar phonology but different orthography (e.g. jazz-has). Easier non-conflicting trials had similar orthography and phonology (e.g. dime-lime) or different orthography and phonology (e.g. staff-gain). The modulatory effect from left fusiform gyrus to left inferior parietal lobule was stronger in controls than in children with reading difficulties only for conflicting trials. Modulatory effects from left fusiform gyrus and left inferior parietal lobule to left inferior frontal gyrus were stronger for conflicting trials than for non-conflicting trials only in control children but not in children with reading difficulties. Modulatory effects from left inferior frontal gyrus to inferior parietal lobule, from medial frontal gyrus to left inferior parietal lobule, and from left inferior parietal lobule to medial frontal gyrus were positively correlated with reading skill only in control children. These findings suggest that children with reading difficulties have deficits in integrating orthography and phonology utilizing left inferior parietal lobule, and in engaging phonological rehearsal/segmentation utilizing left inferior frontal gyrus possibly through the indirect pathway connecting posterior to anterior language processing regions, especially when the orthographic and phonological information is conflicting. PMID:18226833

  1. Effects of land use on lake nutrients: The importance of scale, hydrologic connectivity, and region

    USGS Publications Warehouse

    Soranno, Patricia A.; Cheruvelil, Kendra Spence; Wagner, Tyler; Webster, Katherine E.; Bremigan, Mary Tate

    2015-01-01

    Catchment land uses, particularly agriculture and urban uses, have long been recognized as major drivers of nutrient concentrations in surface waters. However, few simple models have been developed that relate the amount of catchment land use to downstream freshwater nutrients. Nor are existing models applicable to large numbers of freshwaters across broad spatial extents such as regions or continents. This research aims to increase model performance by exploring three factors that affect the relationship between land use and downstream nutrients in freshwater: the spatial extent for measuring land use, hydrologic connectivity, and the regional differences in both the amount of nutrients and effects of land use on them. We quantified the effects of these three factors that relate land use to lake total phosphorus (TP) and total nitrogen (TN) in 346 north temperate lakes in 7 regions in Michigan, USA. We used a linear mixed modeling framework to examine the importance of spatial extent, lake hydrologic class, and region on models with individual lake nutrients as the response variable, and individual land use types as the predictor variables. Our modeling approach was chosen to avoid problems of multi-collinearity among predictor variables and a lack of independence of lakes within regions, both of which are common problems in broad-scale analyses of freshwaters. We found that all three factors influence land use-lake nutrient relationships. The strongest evidence was for the effect of lake hydrologic connectivity, followed by region, and finally, the spatial extent of land use measurements. Incorporating these three factors into relatively simple models of land use effects on lake nutrients should help to improve predictions and understanding of land use-lake nutrient interactions at broad scales.

  2. Effects of Land Use on Lake Nutrients: The Importance of Scale, Hydrologic Connectivity, and Region

    PubMed Central

    Soranno, Patricia A.; Cheruvelil, Kendra Spence; Wagner, Tyler; Webster, Katherine E.; Bremigan, Mary Tate

    2015-01-01

    Catchment land uses, particularly agriculture and urban uses, have long been recognized as major drivers of nutrient concentrations in surface waters. However, few simple models have been developed that relate the amount of catchment land use to downstream freshwater nutrients. Nor are existing models applicable to large numbers of freshwaters across broad spatial extents such as regions or continents. This research aims to increase model performance by exploring three factors that affect the relationship between land use and downstream nutrients in freshwater: the spatial extent for measuring land use, hydrologic connectivity, and the regional differences in both the amount of nutrients and effects of land use on them. We quantified the effects of these three factors that relate land use to lake total phosphorus (TP) and total nitrogen (TN) in 346 north temperate lakes in 7 regions in Michigan, USA. We used a linear mixed modeling framework to examine the importance of spatial extent, lake hydrologic class, and region on models with individual lake nutrients as the response variable, and individual land use types as the predictor variables. Our modeling approach was chosen to avoid problems of multi-collinearity among predictor variables and a lack of independence of lakes within regions, both of which are common problems in broad-scale analyses of freshwaters. We found that all three factors influence land use-lake nutrient relationships. The strongest evidence was for the effect of lake hydrologic connectivity, followed by region, and finally, the spatial extent of land use measurements. Incorporating these three factors into relatively simple models of land use effects on lake nutrients should help to improve predictions and understanding of land use-lake nutrient interactions at broad scales. PMID:26267813

  3. Chromosome abnormalities in glioma

    SciTech Connect

    Li, Y.S.; Ramsay, D.A.; Fan, Y.S.

    1994-09-01

    Cytogenetic studies were performed in 25 patients with gliomas. An interesting finding was a seemingly identical abnormality, an extra band on the tip of the short arm of chromosome 1, add(1)(p36), in two cases. The abnormality was present in all cells from a patient with a glioblastoma and in 27% of the tumor cells from a patient with a recurrent irradiated anaplastic astrocytoma; in the latter case, 7 unrelated abnormal clones were identified except 4 of those clones shared a common change, -Y. Three similar cases have been described previously. In a patient with pleomorphic astrocytoma, the band 1q42 in both homologues of chromosome 1 was involved in two different rearrangements. A review of the literature revealed that deletion of the long arm of chromosome 1 including 1q42 often occurs in glioma. This may indicate a possible tumor suppressor gene in this region. Cytogenetic follow-up studies were carried out in two patients and emergence of unrelated clones were noted in both. A total of 124 clonal breakpoints were identified in the 25 patients. The breakpoints which occurred three times or more were: 1p36, 1p22, 1q21, 1q25, 3q21, 7q32, 8q22, 9q22, 16q22, and 22q13.

  4. [Congenital foot abnormalities].

    PubMed

    Delpont, M; Lafosse, T; Bachy, M; Mary, P; Alves, A; Vialle, R

    2015-03-01

    The foot may be the site of birth defects. These abnormalities are sometimes suspected prenatally. Final diagnosis depends on clinical examination at birth. These deformations can be simple malpositions: metatarsus adductus, talipes calcaneovalgus and pes supinatus. The prognosis is excellent spontaneously or with a simple orthopedic treatment. Surgery remains outstanding. The use of a pediatric orthopedist will be considered if malposition does not relax after several weeks. Malformations (clubfoot, vertical talus and skew foot) require specialized care early. Clubfoot is characterized by an equine and varus hindfoot, an adducted and supine forefoot, not reducible. Vertical talus combines equine hindfoot and dorsiflexion of the forefoot, which is performed in the midfoot instead of the ankle. Skew foot is suspected when a metatarsus adductus is resistant to conservative treatment. Early treatment is primarily orthopedic at birth. Surgical treatment begins to be considered after walking age. Keep in mind that an abnormality of the foot may be associated with other conditions: malposition with congenital hip, malformations with syndromes, neurological and genetic abnormalities. PMID:25524290

  5. The effects of methylphenidate on resting-state striatal., thalamic and global functional connectivity in healthy adults

    PubMed Central

    Farr, Olivia M.; Zhang, Sheng; Hu, Sien; Matuskey, David; Abdelghany, Osama; Malison, Robert T.; Li, Chiang-shan R.

    2015-01-01

    By blocking dopamine and norepinephrine transporters, methylphenidate affects cognitive performance and regional brain activation in healthy individuals as well as those with neuropsychiatric disorders. Resting-state connectivity evaluates the functional integrity of a network of brain regions. Here, we examined how methylphenidate effects resting-state functional connectivity of the dorsal striatum and thalamus, areas each with dense dopaminergic and noradrenergic innervations, as well as global cerebral connectivity. We administered a single, oral dose (45 mg) to 24 healthy adults and compared resting-state connectivity to 24 demographically matched adults who did not receive any medication. The results showed that methylphenidate alters seed-based and global connectivity between the thalamus/dorsal striatum with primary motor cortex, amygdala/hippocampus and frontal executive areas (p<0.05, corrected). Specifically, while methylphenidate at this dosage enhances connectivity to the motor cortex and memory circuits, it dampens prefrontal cortical connectivity perhaps by increasing catecholaminergic signalling past the ‘optimal’ level. These findings advance our understanding of a critical aspect of the multifaceted effects of methylphenidate on brain functions. The results may also facilitate future studies of the aetiology and treatment of neurological and psychiatric disorders that implicate catecholaminergic dysfunction. PMID:24825078

  6. Left-Hemispheric Microstructural Abnormalities in Children With High Functioning Autism Spectrum Disorder

    PubMed Central

    Peterson, Daniel; Mahajan, Rajneesh; Crocetti, Deana; Mejia, Amanda; Mostofsky, Stewart

    2014-01-01

    Current theories of the neurobiological basis of Autism Spectrum Disorder (ASD) posit an altered pattern of connectivity in large-scale brain networks. Here we used Diffusion Tensor Imaging to investigate the microstructural properties of the white matter that mediates inter-regional connectivity in 36 high-functioning children with ASD (HF-ASD), as compared to 37 controls. By employing an atlas-based analysis using LDDMM registration, a widespread, but left-lateralized pattern of abnormalities was revealed. The Mean Diffusivity (MD) of water in the white matter of HF-ASD children was significantly elevated throughout the left hemisphere, particularly in the outer-zone cortical white matter. Across diagnostic groups there was a significant effect of age on left hemisphere MD, with a similar reduction in MD during childhood in both TD and HF-ASD children. The increased MD in children with HF-ASD suggests hypomyelination, and may reflect increased short-range cortico-cortical connections subsequent to early white matter overgrowth. These findings also highlight left hemispheric connectivity as relevant to the pathophysiology of ASD, and indicate that the spatial distribution of microstructural abnormalities in HF-ASD is widespread, and left-lateralized. This altered left-hemispheric connectivity may contribute to deficits in communication and praxis observed in ASD. PMID:25256103

  7. Effects of chronic beta-adrenergic blockade on the left ventricular and cardiocyte abnormalities of chronic canine mitral regurgitation.

    PubMed Central

    Tsutsui, H; Spinale, F G; Nagatsu, M; Schmid, P G; Ishihara, K; DeFreyte, G; Cooper, G; Carabello, B A

    1994-01-01

    The mechanism by which beta blockade improves left ventricular dysfunction in various cardiomyopathies has been ascribed to improved contractile function of the myocardium or to improved beta-adrenergic responsiveness. In this study we tested two hypotheses: (a) that chronic beta blockade would improve the left ventricular dysfunction which develops in mitral regurgitation, and (b) that an important mechanism of this effect would be improved innate contractile function of the myocardium. Two groups of six dogs with chronic severe mitral regurgitation were studied. After 3 mo both groups had developed similar and significant left ventricular dysfunction. One group was then gradually beta-blocked while the second group continued to be observed without further intervention. In the group that remained unblocked, contractile function remained depressed. However, in the group that received chronic beta blockade, contractile function improved substantially. The contractility of cardiocytes isolated from the unblocked hearts and then studied in the absence of beta receptor stimulation was extremely depressed. However, contractility of cardiocytes isolated from the beta-blocked ventricles was virtually normal. Consistent with these data, myofibrillar density was much higher, 55 +/- 4% in the beta-blocked group vs. 39 +/- 2% (P < 0.01) in the unblocked group; thus, there were more contractile elements to generate force in the beta-blocked group. We conclude that chronic beta blockade improves left ventricular function in chronic experimental mitral regurgitation. This improvement was associated with an improvement in the innate contractile function of isolated cardiocytes, which in turn is associated with an increase in the number of contractile elements. Images PMID:7911128

  8. Genotoxic effects and serum abnormalities in residents of regions proximal to e-waste disposal facilities in Jinghai, China.

    PubMed

    Li, KeQiu; Liu, ShaSha; Yang, QiaoYun; Zhao, YuXia; Zuo, JunFang; Li, Ran; Jing, YaQing; He, XiaoBo; Qiu, XingHua; Li, Guang; Zhu, Tong

    2014-07-01

    Electronic waste (e-waste) disposal is a growing problem in China, and its effects on human health are a concern. To determine the concentrations of pollutants in peripheral blood and genetic aberrations near an e-waste disposal area in Jinghai, China, blood samples were collected from 30 (age: 41±11.01 years) and 28 (age: 33±2.14 years) individuals residing within 5 and 40km of e-waste disposal facilities in Jinghai (China), respectively, during the week of October 21-28, 2011. Levels of inorganic pollutants (calcium, copper, iron, lead, magnesium, selenium, and zinc) and malondialdehyde (MDA), identities of persistent organic pollutants (POPs), micronucleus rates, and lymphocyte subsets were analyzed in individuals. Total RNA expression profiles were analyzed by group and gender. The population group living in proximity to the e-waste site displayed significantly higher mean levels of copper, zinc, lead, MDAs, POPs (B4-6DE, B7-9DE, total polychlorinated biphenyls, and BB-153). In addition, micronucleus rates of close-proximity group were higher compared with the remote group (18.27% vs. 7.32%). RNA expression of genes involved in metal ion binding and transport, oxidation/reduction, immune defense, and tumorigenesis varied between groups, with men most detrimentally affected (p<0.05). CD4(+)/CD8(+)T cell ratios, CD4(+)CD25(nt/hi)CD127(lo)regulatory T cell percentages, and CD95 expression were greater in the e-waste group (p<0.05). Residing in close proximity to e-waste disposal facilities (≤5km) may be associated with the accumulation of potentially harmful inorganic/organic compounds and gender-preferential genetic aberrations. PMID:24785710

  9. Random forest Granger causality for detection of effective brain connectivity using high-dimensional data.

    PubMed

    Furqan, Mohammad Shaheryar; Siyal, Mohammad Yakoob

    2016-03-01

    Studies have shown that the brain functions are not localized to isolated areas and connections but rather depend on the intricate network of connections and regions inside the brain. These networks are commonly analyzed using Granger causality (GC) that utilizes the ordinary least squares (OLS) method for its standard implementation. In the past, several approaches have shown to solve the limitations of OLS by using diverse regularization systems. However, there are still some shortcomings in terms of accuracy, precision, and false discovery rate (FDR). In this paper, we are proposing a new strategy to use Random Forest as a regularization technique for computing GC that will improve these shortcomings. We have demonstrated the effectiveness of our proposed methodology by comparing the results with existing Least absolute shrinkage and selection operator (LASSO), and Elastic-Net regularized implementations of GC using simulated dataset. Later, we have used our proposed approach to map the network involved during deductive reasoning using real StarPlus dataset. PMID:26620192

  10. I Want It, You've Got It - Effectively Connect Users to Geospatial Resources

    NASA Astrophysics Data System (ADS)

    White, C. E.

    2012-12-01

    How do users of scientific data find what they need? How do they know where to look, what to look for, how to evaluate, and - if they find the right resource - then how to get it? When the data is of a geospatial nature, other factors also come into play - is the data in a format/projection compatible with other data being used, does the user have access to tools that can analyze and display the data to adequately evaluate it, and does the user have knowledge on how to manage that access - especially if the data is being exposed by web services. Supporting users to connect them to geospatial data in a continually evolving technological climate is a challenge that reaches deeply into all levels of data management. In this talk, we will discuss specific challenges in how users discover and access resources, and how Esri has evolved solutions over time to more effectively connect users to what they need. Some of the challenges - and current solutions - that will be discussed are: balancing a straightforward user experience with rich functionality, providing simple descriptions while maintaining complete metadata, enabling data access to work with an organization's content while being compatible with other organizations' access mechanisms, and the ability to publish data once yet share it in many venues.

  11. The effect of a positioning index on the biomechanical stability of tapered implant-abutment connections.

    PubMed

    Villarinho, Eduardo Aydos; Cervieri, André; Shinkai, Rosemary Sadami Arai; Grossi, Márcio Lima; Teixeira, Eduardo Rolim

    2015-04-01

    The biomechanical stability of the implant-abutment connection is critical for the success of implant-supported restorations. This study investigated the effect of a positioning index on the abutment screw preload values of tapered connection implants. Twenty Morse taper implants presenting an internal locking hex received 10 solid and 10 straight screw retained abutments for cemented single-crown restorations. Ten abutments had a positioning index to fit the internal locking hex of the implant (straight), and 10 were locked only by the implant taper (solid). The preload values for each abutment screw after a tightening torque were registered by strain gauges. Prosthetic crowns were placed on each abutment and subjected to mechanical cycling. Detorque forces were applied to each abutment and compared with the initial torque values. Data were statistically analyzed using Kolmogorov-Smirnov and Student t tests. The nonindexed group presented higher initial preload (6.05 N ± 0.95 N) compared with the indexed group (4.88 N ± 0.92 N; P < .05). After cycling, the nonindexed group exhibited less reduction of preload (13.84% ± 6.43%) compared with the indexed group (52.65% ± 14.81%; P < .01). Indexed tapered abutments for single-crown restorations might represent greater biomechanical risk under function. PMID:23641735

  12. Dynamics of Functional and Effective Connectivity Within Human Cortical Motor Control Networks

    PubMed Central

    Ewen, Joshua B.; Lakshmanan, Balaji M.; Hallett, Mark; Mostofsky, Stewart H.; Crone, Nathan E.; Korzeniewska, Anna

    2014-01-01

    Objective Praxis, the performance of complex motor gestures, is crucial to the development of motor and social/communicative capacities. Praxis relies on a network consisting of inferior parietal and premotor regions, particularly on the left, and is thought to require transformation of spatio-temporal representations (parietal) into movement sequences (premotor). Method We examined praxis network dynamics by measuring EEG effective connectivity while healthy subjects performed a praxis task. Results Propagation from parietal to frontal regions was not statistically greater on the left than the right. However, propagation from left parietal regions to all other regions was significantly greater during gesture preparation than execution. Moreover, during gesture preparation only, propagation from the left parietal region to bilateral frontal regions was greater than reciprocal propagations to the left parietal region. This directional specificity was not observed for the right parietal region. Conclusions These findings represent direct electrophysiological evidence for directionally predominant propagation in left frontal-parietal networks during praxis behavior, which may reflect neural mechanisms by which representations in the human brain select appropriate motor sequences for subsequent execution. Significance In addition to bolstering the classic view of praxis network function, these results also demonstrate the relevance of additional information provided by directed connectivity measures. PMID:25270239

  13. Effective connectivity of neural pathways underlying disgust by multivariate Granger causality analysis

    NASA Astrophysics Data System (ADS)

    Yan, Hao; Wang, Yonghui; Tian, Jie; Liu, Yijun

    2011-03-01

    The disgust system arises phylogenetically in response to dangers to the internal milieu from pathogens and their toxic products. Functional imaging studies have demonstrated that a much wider range of neural structures was involved in triggering disgust reactions. However, less is known regarding how and what neural pathways these neural structures interact. To address this issue, we adopted an effective connectivity based analysis, namely the multivariate Granger causality approach, to explore the causal interactions within these brain networks. Results presented that disgust can induce a wide range of brain activities, such as the insula, the anterior cingulate cortex, the parahippocampus lobe, the dorsal lateral prefrontal cortex, the superior occipital gyrus, and the supplementary motor cortex. These brain areas constitute as a whole, with much denser connectivity following disgust stimuli, in comparison with that of the neutral condition. Moreover, the anterior insula, showing multiple casual interactions with limbic and subcortical areas, was implicated as a central hub in organizing multiple information processing in the disgust system.

  14. Abnormal pressures as hydrodynamic phenomena

    USGS Publications Warehouse

    Neuzil, C.E.

    1995-01-01

    So-called abnormal pressures, subsurface fluid pressures significantly higher or lower than hydrostatic, have excited speculation about their origin since subsurface exploration first encountered them. Two distinct conceptual models for abnormal pressures have gained currency among earth scientists. The static model sees abnormal pressures generally as relict features preserved by a virtual absence of fluid flow over geologic time. The hydrodynamic model instead envisions abnormal pressures as phenomena in which flow usually plays an important role. This paper develops the theoretical framework for abnormal pressures as hydrodynamic phenomena, shows that it explains the manifold occurrences of abnormal pressures, and examines the implications of this approach. -from Author

  15. Effects on electrical distribution networks of dispersed power generation at high levels of connection penetration

    SciTech Connect

    Longrigg, P

    1983-07-01

    The advent and deployment of significant levels of photovoltaic and wind energy generation in the spatially dispersed mode (i.e., residential and intermediate load centers) may have deleterious effects upon existing protective relay equipment and its time-current coordination on radial distribution circuits to which power conditioning equipment may be connected for power sell-back purposes. The problems that may arise involve harmonic injection from power conditioning inverters that can affect protective relays and cause excessive voltage and current from induced series and parallel resonances on feeders and connected passive equipment. Voltage regulation, var requirements, and consumer metering can also be affected by this type of dispersed generation. The creation of islands of supply is also possible, particularly on rural supply systems. This paper deals mainly with the effects of harmonics and short-circuit currents from wind energy conversion systems (WECS) and photovoltaic (PV) systems upon the operating characteristics of distribution networks and relays and other protective equipment designed to ensure the safety and supply integrity of electrical utility networks. Traditionally, electrical supply networks have been designed for one-way power flow-from generation to load, with a balance maintained between the two by means of automatic generation and load-frequency controls. Dispersed generation, from renewables like WECS or PV or from nonrenewable resources, can change traditional power flow. These changes must be dealt with effectively if renewable energy resources are to be integrated into the utility distribution system. This paper gives insight into these problems and proposes some solutions.

  16. Making chromosome abnormalities treatable conditions.

    PubMed

    Cody, Jannine DeMars; Hale, Daniel Esten

    2015-09-01

    Individuals affected by the classic chromosome deletion syndromes which were first identified at the beginning of the genetic age, are now positioned to benefit from genomic advances. This issue highlights five of these conditions (4p-, 5p-, 11q-, 18p-, and 18q-). It focuses on the increased in understanding of the molecular underpinnings and envisions how these can be transformed into effective treatments. While it is scientifically exciting to see the phenotypic manifestations of hemizygosity being increasingly understood at the molecular and cellular level, it is even more amazing to consider that we are now on the road to making chromosome abnormalities treatable conditions. PMID:26351122

  17. Feeling Abnormal: Simulation of Deviancy in Abnormal and Exceptionality Courses.

    ERIC Educational Resources Information Center

    Fernald, Charles D.

    1980-01-01

    Describes activity in which student in abnormal psychology and psychology of exceptional children classes personally experience being judged abnormal. The experience allows the students to remember relevant research, become sensitized to the feelings of individuals classified as deviant, and use caution in classifying individuals as abnormal.…

  18. Medical management of abnormal pregnancy.

    PubMed

    Ratnam, S S; Prasad, R N

    1990-06-01

    Medical termination of abnormal pregnancy requires specific techniques since some conditions make therapy more effective, e.g., missed abortion intrauterine death and molar pregnancy, and others less so, e.g. anencephalic pregnancy. In all cases it is best to terminate the pregnancy as soon as possible to reduce anguish and risks of complications such as consumptive coagulopathy. Oxytocin is not consistently effective, but intraamniotic rivanol has oxytocic properties, and prostaglandins (PGs) are effective by several routes. Surgical methods are more popular in Japan and the US. A diagnostic flow chart is included and described. For missed abortion and fetal death vacuum aspiration or dilatation and evacuation are appropriate for early pregnancy, or PGs are used for later pregnancy, unless there are medical contraindications. Anencephalic pregnancy, usually diagnoses in 2nd or 3rd trimester, is resistant to medical therapy and must often be terminated by cesarean section. Molar pregnancy can be managed with vacuum aspiration at any length of gestation, but must be completed by curettage. Intraamniotic PGs are not advised for mole or fetal death. PG analogs can be administered intramuscularly, or vaginally in gel form. Other types of abnormal pregnancy that can be managed with PGs are spina bifida, hydrocephalus, hydrops fetalis, Dandy-Walker syndrome and Down's syndrome. Tubal pregnancy can be evacuated with intratubally administered PGs under laparoscopic control, thereby preserving tubal integrity. PMID:2225605

  19. Disrupted resting-state insular subregions functional connectivity in post-traumatic stress disorder.

    PubMed

    Zhang, Youxue; Xie, Bing; Chen, Heng; Li, Meiling; Guo, Xiaonan; Chen, Huafu

    2016-07-01

    Post-traumatic stress disorder (PTSD) is suggested to be a structural and functional abnormality in the insula. The insula, which consists of distinct subregions with various patterns of connectivity, displays complex and diverse functions. However, whether these insular subregions have different patterns of connectivity in PTSD remains unclear. Investigating the abnormal functional connectivity of the insular subregions is crucial to reveal its potential effect on diseases specifically PTSD. This study uses a seed-based method to investigate the altered resting-state functional connectivity of insular subregions in PTSD. We found that patients with PTSD showed reduced functional connectivity compared with healthy controls (HCs) between the left ventral anterior insula and the anterior cingulate cortex. The patients with PTSD also exhibited decreased functional connectivity between the right posterior insula and left inferior parietal lobe, and the postcentral gyrus relative to HCs. These results suggest the involvement of altered functional connectivity of insular subregions in the abnormal regulation of emotion and processing of somatosensory information in patients with PTSD. Such impairments in functional connectivity patterns of the insular subregions may advance our understanding of the pathophysiological basis underlying PTSD. PMID:27399097

  20. Identification and validation of effective connectivity networks in functional magnetic resonance imaging using switching linear dynamic systems.

    PubMed

    Smith, Jason F; Pillai, Ajay; Chen, Kewei; Horwitz, Barry

    2010-09-01

    Dynamic connectivity networks identify directed interregional interactions between modeled brain regions in neuroimaging. However, problems arise when the regions involved in a task and their interconnections are not fully known a priori. Objective measures of model adequacy are necessary to validate such models. We present a connectivity formalism, the Switching Linear Dynamic System (SLDS), that is capable of identifying both Granger-Geweke and instantaneous connectivity that vary according to experimental conditions. SLDS explicitly models the task condition as a Markov random variable. The series of task conditions can be estimated from new data given an identified model providing a means to validate connectivity patterns. We use SLDS to model functional magnetic resonance imaging data from five regions during a finger alternation task. Using interregional connectivity alone, the identified model predicted the task condition vector from a different subject with a different task ordering with high accuracy. In addition, important regions excluded from a model can be identified by augmenting the model state space. A motor task model excluding primary motor cortices was augmented with a new neural state constrained by its connectivity with the included regions. The augmented variable time series, convolved with a hemodynamic kernel, was compared to all brain voxels. The right primary motor cortex was identified as the best region to add to the model. Our results suggest that the SLDS model framework is an effective means to address several problems with modeling connectivity including measuring overall model adequacy and identifying important regions missing from models. PMID:19969092

  1. Photothermal effects in connective tissues mediated by laser-activated gold nanorods.

    PubMed

    Ratto, Fulvio; Matteini, Paolo; Rossi, Francesca; Menabuoni, Luca; Tiwari, Neha; Kulkarni, Sulabha K; Pini, Roberto

    2009-06-01

    We report a study on the application of laser-activated nanoparticles in the direct welding of connective tissues, which may become a valuable technology in biomedicine. We use colloidal gold nanorods as new near-infrared chromophores to mediate functional photothermal effects in the eye lens capsules. Samples obtained ex vivo from porcine eyes are treated to simulate heterotransplants with 810-nm diode laser radiation in association with a stain of gold nanorods of aspect ratio approximately 4. This stain is applied at the interface between a patch of capsule from a donor eye and the capsule of a recipient eye. Then, by administration of laser pulses of 40 msec and approximately 100-140 J/cm(2), we achieved the local denaturation of the endogenous collagen filaments, which reveals that the treated area reached temperatures above 50 degrees C. The thermal damage is confined within 50-70 mum in a radial distance from the irradiated area. PMID:19223241

  2. Abnormal human sex chromosome constitutions

    SciTech Connect

    1993-12-31

    Chapter 22, discusses abnormal human sex chromosome constitution. Aneuploidy of X chromosomes with a female phenotype, sex chromosome aneuploidy with a male phenotype, and various abnormalities in X chromosome behavior are described. 31 refs., 2 figs.

  3. Exercises to Improve Gait Abnormalities

    MedlinePlus

    ... Home About iChip Articles Directories Videos Resources Contact Exercises to Improve Gait Abnormalities Home » Article Categories » Exercise and Fitness Font Size: A A A A Exercises to Improve Gait Abnormalities Next Page The manner ...

  4. Effects of exercise and respiration on hemodynamic efficiency in CFD simulations of the total cavopulmonary connection.

    PubMed

    Marsden, Alison L; Vignon-Clementel, Irene E; Chan, Frandics P; Feinstein, Jeffrey A; Taylor, Charles A

    2007-02-01

    Congenital heart defects with a single functional ventricle, such as hypoplastic left heart syndrome and tricuspid atresia, require a staged surgical approach to separate the systemic and pulmonary circulations. Ultimately, the venous or pulmonary side of the heart is bypassed by directly connecting the vena cava to the pulmonary arteries with a modified t-shaped junction. The Fontan procedure (total cavopulmonary connection, TCPC) completes this process of separation. To date, computational fluid dynamics (CFD) simulations in this low pressure, passive flow, intrathoracic system have neglected the presumed important effects of respiration on physiology and higher "stress" states such as with exercise have never been considered. We hypothesize that incorporating effects of respiration and exercise would provide more realistic estimates of TCPC performance. Time-dependent, 3D blood flow simulations are performed by a custom finite element solver for two patient-specific Fontan models with a novel respiration model, developed to generate physiologic time-varying flow conditions. Blood flow features, pressure, and energy efficiency are analyzed at rest and with increasing flow rates to simulate exercise conditions. The simulations produce realistic pressure and flow data, comparable to that measured by catheterization and echocardiography, and demonstrate substantial increases in energy dissipation (i.e. decreased performance) with exercise and respiration due to increasing intensity of small scale vortices in the flow. As would be expected, these changes are highly dependent on patient-specific anatomy and Fontan geometry. We propose that respiration and exercise should be incorporated into TCPC CFD simulations to provide increasingly realistic evaluations of TCPC performance. PMID:17171509

  5. Activity and effective connectivity of parietal and occipital cortical regions during haptic shape perception.

    PubMed

    Peltier, Scott; Stilla, Randall; Mariola, Erica; LaConte, Stephen; Hu, Xiaoping; Sathian, K

    2007-02-01

    It is now widely accepted that visual cortical areas are active during normal tactile perception, but the underlying mechanisms are still not clear. The goal of the present study was to use functional magnetic resonance imaging (fMRI) to investigate the activity and effective connectivity of parietal and occipital cortical areas during haptic shape perception, with a view to potentially clarifying the role of top-down and bottom-up inputs into visual areas. Subjects underwent fMRI scanning while engaging in discrimination of haptic shape or texture, and in separate runs, visual shape or texture. Accuracy did not differ significantly between tasks. Haptic shape-selective regions, identified on a contrast between the haptic shape and texture conditions in individual subjects, were found bilaterally in the postcentral sulcus (PCS), multiple parts of the intraparietal sulcus (IPS) and the lateral occipital complex (LOC). The IPS and LOC foci tended to be shape-selective in the visual modality as well. Structural equation modelling was used to study the effective connectivity among the haptic shape-selective regions in the left hemisphere, contralateral to the stimulated hand. All possible models were tested for their fit to the correlations among the observed time-courses of activity. Two equivalent models emerged as the winners. These models, which were quite similar, were characterized by both bottom-up paths from the PCS to parts of the IPS, and top-down paths from the LOC and parts of the IPS to the PCS. We conclude that interactions between unisensory and multisensory cortical areas involve bidirectional information flow. PMID:16616940

  6. Effects of rearfoot-controlling orthotic treatment on dorsiflexion of the hallux in feet with abnormal subtalar pronation: a preliminary report.

    PubMed

    Munuera, Pedro V; Domínguez, Gabriel; Palomo, Inmaculada C; Lafuente, Guillermo

    2006-01-01

    The aim of this study was to determine whether the treatment of abnormal subtalar pronation restores functional (as opposed to structural) limited dorsiflexion of the first metatarsophalangeal joint (functional hallux limitus). We studied 16 feet of eight individuals with abnormal subtalar pronation. Orthoses were made for all of the feet, and hallux dorsiflexion was measured during weightbearing. Each patient was unshod without the orthosis, unshod with the orthosis fitted on the same day, and unshod with the orthosis fitted approximately 5 months later. The results suggest that in functional hallux limitus caused by abnormal subtalar pronation, hallux dorsiflexion will gradually be restored by the use of foot orthoses to control the abnormal subtalar pronation. PMID:16868319

  7. Fermionic q-deformation and its connection to thermal effective mass of a quasiparticle

    NASA Astrophysics Data System (ADS)

    Algin, Abdullah; Senay, Mustafa

    2016-04-01

    A fermionic deformation scheme is applied to a study on the low-temperature quantum statistical behavior of a quasifermion gas model with intermediate statistics. Such a model does not satisfy the Pauli exclusion principle, and its quantum statistical properties are based on a formalism of the fermionic q-calculus. For low temperatures, several thermostatistical functions of the model such as the chemical potential, the heat capacity, and the entropy are derived by means of a function of the model deformation parameter q. The effect of fermionic q-deformation on the low-temperature thermostatistical properties of the model are discussed in detail. Our results show that the present deformed (quasi)fermion model provides remarkable connections of the model deformation parameter q, first, with the thermal effective mass of a quasiparticle, and second, with the temperature parameter. Hence, it turns out that the model deformation parameter q has also a role controlling the strength of effective quasiparticle interactions in the model. Finally, we conclude that this work can be useful for understanding the details of interaction mechanism of fermions such as quasiparticle states emergent in the fractional quantum Hall effect.

  8. Nonlinear system identification of frictional effects in a beam with a bolted joint connection

    NASA Astrophysics Data System (ADS)

    Eriten, Melih; Kurt, Mehmet; Luo, Guanyang; Michael McFarland, D.; Bergman, Lawrence A.; Vakakis, Alexander F.

    2013-08-01

    We perform nonlinear system identification (NSI) of the effects of frictional connections in the dynamics of a bolted beam assembly. The methodology utilized in this work combines experimental measurements with slow-flow dynamic analysis and empirical mode decomposition, and reconstructs the dynamics through reduced-order models. These are in the form of single-degree-of-freedom linear oscillators (termed intrinsic modal oscillators—IMOs) with forcing terms derived directly from the experimental measurements through slow-flow analysis. The derived reduced order models are capable of reproducing the measured dynamics, whereas the forcing terms provide important information about nonlinear damping effects. The NSI methodology is applied to model nonlinear friction effects in a bolted beam assembly. A 'monolithic' beam with identical geometric and material properties is also tested for comparison. Three different forcing (energy) levels were considered in the tests in order to study the energy-dependencies of the damping nonlinearities induced in the beam from the bolted joint. In all cases, the NSI methodology employed was successful in identifying the damping nonlinearities, their spatial distributions and their effects of the vibration modes of the structural component.

  9. On the Effect of Connectivity on Solute Transport in Spatially Heterogeneous Combined Unsaturated-Saturated Flow Systems

    NASA Astrophysics Data System (ADS)

    Russo, David

    2016-04-01

    Detailed numerical analyses of flow and transport were used to investigate the effect of spatially connected features on the transport in three-dimensional (3-D), spatially heterogeneous, combined vadose zone-groundwater flow systems. Formations with spatially connected fine- and coarse-textured features (SCFT- and SCCT-formations, respectively), representing the10th and the 90th percentiles of the distributions of the formation's hydraulic parameters, respectively, were considered here. Results of the analyses suggest that in steady-state flow, when the unsaturated zone of the combined flow domains is relatively wet, as compared with a Multivariate-Gaussian (MG) formation, spatially connected features may reduce the solute first arrival time, particularly in the SCCT-formation, and may enhance the spreading of the solute breakthrough, particularly in the SCFT-formation. The effect of the spatially connected features on the hydrological response, however, decreases as the unsaturated zone becomes drier. The latter result stems from the decrease in the fraction of the water-filled, pore-space occupied by the connected structures, with decreasing water content. The latter finding also explains the result that the response of more realistic, combined flow systems, whose unsaturated zone is associated with transient flow and relatively low, intermittent water contents, is essentially independent of the spatially connected features of the formations, regardless of their soil texture.

  10. On the effect of connectivity on solute transport in spatially heterogeneous combined unsaturated-saturated flow systems

    NASA Astrophysics Data System (ADS)

    Russo, David

    2015-05-01

    Detailed numerical analyses of flow and transport were used to investigate the effect of spatially connected features on transport in three-dimensional (3-D), spatially heterogeneous, combined vadose zone-groundwater flow systems. Formations with spatially connected fine-textured and coarse-textured features (F-formation and C-formation, respectively), representing the10th and the 90th percentiles of the distributions of the formation's hydraulic parameters, respectively, were considered here. Results of the analyses suggest that in steady state flow, when the unsaturated zone of the combined flow domains is relatively wet, as compared with a Multivariate-Gaussian (MG) formation, spatially connected features may reduce the solute first arrival time, particularly in the C-formation, and may enhance the spreading of the solute breakthrough, particularly in the F-formation. The effect of the spatially connected features on the hydrological response, however, decreases as the unsaturated zone becomes drier. The latter result stems from the decrease in the fraction of the water-filled, pore-space occupied by the connected structures, with decreasing water content. The latter finding also explains the result that the response of more realistic, combined flow systems, whose unsaturated zone is associated with relatively low, intermittent water contents, is essentially independent of the spatially connected features of the formations, regardless of their soil texture.

  11. Effects of metabolic and myocardial microcirculatory abnormalities on the pathogenesis of cardiac autonomic neuropathy in type 2 diabetes mellitus: A prospective study in Japanese patients*

    PubMed Central

    Komori, Hiromi

    2005-01-01

    Background: In diabetic patients, cardiac autonomic neuropathy is an important factor affecting prognosis. Whether this condition in diabetic patients is caused directly by neurovisceral metabolic disorder and/or indirectly by micro circulation remains to be clarified. Objective: The aim of this study was to determine whether cardiac sympathetic nerve dysfunction can be detected using adenosine triphosphate (ATP) testing, while also investigating the effects of metabolic and/or myocardial microcirculatory abnormalities on the pathogenesis of cardiac autonomic nerve dysfunction in patients with type 2 diabetes mellitus (DM-2) in Japan. Methods: This prospective study was performed at the Division of Diabetology Department of Internal Medicine, Toho University, Ohashi Hospital, Tokyo, Japan. Patients aged ≥ 18 years with DM-2 with no abnormalities on electrocardiography (ECG) or echocardiography were enrolled. An ATP thallium (Tl)-201 myocardial scintigraphy test (ATP test) and iodine (I)-123 metaiodobenzylguanidine (MIBG) scintigraphy were performed. ATP was administered by continuous IV infusion over 6 minutes at 0.16 mg/kg · min. Five minutes after the ATP infusion was started, T1-201 111 MBq IV was administered. Single-photon emission computed tomography (SPECT) imaging was begun immediately after the end of ATP infusion and was completed 3 hours after stress to show washout from stress to rest. I-123 MIBG 111 MBq IV was administered. A planar image from the front side and a SPECT image (early phase) was obtained 15 to 30 minutes later. After 3 hours, a planar image from the front side and a SPECT image (late phase) were obtained to show washout from stress to rest. The mean TI washout rate (ATP-WR) and heart-to-mediastinum (H/M) ratio in the late-phase scintigraphic images and the washout rate of MIBG (MIBG-WR) in the left ventricle was determined. The correlations of these measurements with the mean values of glycosylated hemoglobin (HbA1c) and fasting

  12. Abnormal thermal expansion, multiple transitions, magnetocaloric effect, and electronic structure of Gd{sub 6}Co{sub 4.85}

    SciTech Connect

    Zhang, Jiliang; Zheng, Zhigang; Shan, Guangcun E-mail: bobev@udel.edu; Bobev, Svilen E-mail: bobev@udel.edu; Shek, Chan Hung E-mail: bobev@udel.edu

    2015-10-07

    The structure of known Gd{sub 4}Co{sub 3} compound is re-determined as Gd{sub 6}Co{sub 4.85}, adopting the Gd{sub 6}Co{sub 1.67}Si{sub 3} structure type, which is characterized by two disorder Co sites filling the Gd octahedral and a short Gd-Gd distance within the octahedra. The compound shows uniaxial negative thermal expansion in paramagnetic state, significant negative expansion in ferromagnetic state, and positive expansion below ca. 140 K. It also exhibits large magnetocaloric effect, with an entropy change of −6.4 J kg{sup −1} K{sup −1} at 50 kOe. In the lattice of the compound, Co atoms at different sites show different spin states. It was confirmed by the X-ray photoelectron spectra and calculation of electronic structure and shed lights on the abnormal thermal expansion. The stability of such compound and the origin of its magnetism are also discussed based on measured and calculated electronic structures.

  13. The effective connectivity of the seizure onset zone and ictal perfusion changes in amygdala kindled rhesus monkeys.

    PubMed

    Cleeren, Evy; Premereur, Elsie; Casteels, Cindy; Goffin, Karolien; Janssen, Peter; Van Paesschen, Wim

    2016-01-01

    Epileptic seizures are network-level phenomena. Hence, epilepsy may be regarded as a circuit-level disorder that cannot be understood outside this context. Better insight into the effective connectivity of the seizure onset zone and the manner in which seizure activity spreads could lead to specifically-tailored therapies for epilepsy. We applied the electrical amygdala kindling model in two rhesus monkeys until these animals displayed consistent stage IV seizures. At this stage, we investigated the effective connectivity of the amygdala by means of electrical microstimulation during fMRI (EM-fMRI). In addition, we imaged changes in perfusion during a seizure using ictal SPECT perfusion imaging. The spatial overlap between the connectivity network and the ictal perfusion network was assessed both at the regional level, by calculating Dice coefficients using anatomically defined regions of interest, and at the voxel level. The kindled amygdala was extensively connected to bilateral cortical and subcortical structures, which in many cases were connected multisynaptically to the amygdala. At the regional level, the spatial extents of many of these fMRI activations and deactivations corresponded to the respective increases and decreases in perfusion imaged during a stage IV seizure. At the voxel level, however, some regions showed residual seizure-specific activity (not overlapping with the EM-fMRI activations) or fMRI-specific activation (not overlapping with the ictal SPECT activations), indicating that frequently, only a part of a region anatomically connected to the seizure onset zone participated in seizure propagation. Thus, EM-fMRI in the amygdala of electrically-kindled monkeys reveals widespread areas that are often connected multisynaptically to the seizure focus. Seizure activity appears to spread, to a large extent, via these connected areas. PMID:27489773

  14. Functional neuroimaging and schizophrenia: a view towards effective connectivity modeling and polygenic risk

    PubMed Central

    Birnbaum, Rebecca; Weinberger, Daniel R.

    2013-01-01

    We review critical trends in imaging genetics as applied to schizophrenia research, and then discuss some future directions of the field. A plethora of imaging genetics studies have investigated the impact of genetic variation on brain function, since the paradigm of a neuroimaging intermediate phenotype for schizophrenia first emerged. It was initially posited that the effects of schizophrenia susceptibility genes would be more penetrant at the level of biologically based neuroimaging intermediate phenotypes than at the level of a complex and phenotypically heterogeneous psychiatric syndrome. The results of many studies support this assumption, most of which show single genetic variants to be associated with changes in activity of localized brain regions, as determined by select cognitive controlled tasks. From these basic studies, functional neuroimaging analysis of intermediate phenotypes has progressed to more complex and realistic models of brain dysfunction, incorporating models of functional and effective connectivity, including the modalities of psycho-physiological interaction, dynamic causal modeling, and graph theory metrics. The genetic association approaches applied to imaging genetics have also progressed to more sophisticated multivariate effects, including incorporation of two-way and three-way epistatic interactions, and most recently polygenic risk models. Imaging genetics is a unique and powerful strategy for understanding the neural mechanisms of genetic risk for complex CNS disorders at the human brain level. PMID:24174900

  15. Effectiveness of Choice Theory Connections: a cross-sectional and comparative analysis of California female inmates.

    PubMed

    Grills, Cheryl; Villanueva, Sandra; Anderson, Michelle; Corsbie-Massay, Charisse L; Smith, Bradley; Johnson, Lester; Owens, Kyri

    2015-06-01

    In the past 30 years, the rates of incarceration and recidivism for women in the United States have increased dramatically. Choice Theory® Connections (CTC) is a gender-tailored pre-release intervention program based on Choice Theory® (Glasser, 1999), and designed to achieve meaningful and sustainable cognitive and behavioral change. This evaluation examines CTC among 96 female participants in a California state prison enrolled in an introductory (n = 58) or advanced (n = 38) course. CTC significantly improved perceived stress, mindfulness, emotion regulation, impulsivity, and well-being on completion; effects were stronger for the introductory cohort, but significant effects also emerged for the advanced cohort. In addition, participants in the advanced cohort reported better scores at baseline, demonstrating the effects of prolonged engagement with the intervention. Results suggest that CTC can improve incarcerated women's well-being pre-release, a strong predictor of recidivism post-release. Further study and wider use of CTC are encouraged. PMID:24441032

  16. Functional neuroimaging and schizophrenia: a view towards effective connectivity modeling and polygenic risk.

    PubMed

    Birnbaum, Rebecca; Weinberger, Daniel R

    2013-09-01

    We review critical trends in imaging genetics as applied to schizophrenia research, and then discuss some future directions of the field. A plethora of imaging genetics studies have investigated the impact of genetic variation on brain function, since the paradigm of a neuroimaging intermediate phenotype for schizophrenia first emerged. It was initially posited that the effects of schizophrenia susceptibility genes would be more penetrant at the level of biologically based neuroimaging intermediate phenotypes than at the level of a complex and phenotypically heterogeneous psychiatric syndrome. The results of many studies support this assumption, most of which show single genetic variants to be associated with changes in activity of localized brain regions, as determined by select cognitive controlled tasks. From these basic studies, functional neuroimaging analysis of intermediate phenotypes has progressed to more complex and realistic models of brain dysfunction, incorporating models of functional and effective connectivity, including the modalities of psycho-physiological interaction, dynamic causal modeling, and graph theory metrics. The genetic association approaches applied to imaging genetics have also progressed to more sophisticated multivariate effects, including incorporation of two-way and three-way epistatic interactions, and most recently polygenic risk models. Imaging genetics is a unique and powerful strategy for understanding the neural mechanisms of genetic risk for complex CNS disorders at the human brain level. PMID:24174900

  17. Emotional face expression modulates occipital-frontal effective connectivity during memory formation in a bottom-up fashion

    PubMed Central

    Xiu, Daiming; Geiger, Maximilian J.; Klaver, Peter

    2015-01-01

    This study investigated the role of bottom-up and top-down neural mechanisms in the processing of emotional face expression during memory formation. Functional brain imaging data was acquired during incidental learning of positive (“happy”), neutral and negative (“angry” or “fearful”) faces. Dynamic Causal Modeling (DCM) was applied on the functional magnetic resonance imaging (fMRI) data to characterize effective connectivity within a brain network involving face perception (inferior occipital gyrus and fusiform gyrus) and successful memory formation related areas (hippocampus, superior parietal lobule, amygdala, and orbitofrontal cortex). The bottom-up models assumed processing of emotional face expression along feed forward pathways to the orbitofrontal cortex. The top-down models assumed that the orbitofrontal cortex processed emotional valence and mediated connections to the hippocampus. A subsequent recognition memory test showed an effect of negative emotion on the response bias, but not on memory performance. Our DCM findings showed that the bottom-up model family of effective connectivity best explained the data across all subjects and specified that emotion affected most bottom-up connections to the orbitofrontal cortex, especially from the occipital visual cortex and superior parietal lobule. Of those pathways to the orbitofrontal cortex the connection from the inferior occipital gyrus correlated with memory performance independently of valence. We suggest that bottom-up neural mechanisms support effects of emotional face expression and memory formation in a parallel and partially overlapping fashion. PMID:25954169

  18. Weakly connected neural nets

    NASA Technical Reports Server (NTRS)

    Zak, Michail

    1990-01-01

    A new neural network architecture is proposed based upon effects of non-Lipschitzian dynamics. The network is fully connected, but these connections are active only during vanishingly short time periods. The advantages of this architecture are discussed.

  19. Modeling activation and effective connectivity of VWFA in same script bilinguals.

    PubMed

    Boukrina, Olga; Hanson, Stephen Jose; Hanson, Catherine

    2014-06-01

    Previous neuroimaging research revealed a small area in the inferior occipito-temporal cortex (VWFA), which seems to be involved in recognition of written words. The specialized response of the VWFA to words could result from repeated exposure to print in the course of functional fine-tuning of the brain. Research with bilingual speakers holds promise in helping to reveal response properties of the VWFA by assessing its sensitivity to language proficiency, word-form similarity, and meaning overlap across two languages. Using fMRI, we compared VWFA activity for cognate and homograph prime-target pairs in a group of fluent Spanish-English speakers. Cognates share form and meaning in two languages, while homographs only share form. Relative to baseline, the VWFA showed repetition suppression to pairs of homographs, but not to pairs of cognates, suggesting that this area is sensitive to word meaning. The different response to cognates and homographs was only observed when English was the prime language and Spanish was the target language. To help explain this result we compared patterns of effective connectivity between the VWFA and other parts of the reading network implicated in semantic and phonological processing. Our neural models showed that English targets engaged a direct ventral route from the VWFA to the frontal lobe and Spanish targets engaged an indirect dorsal route. Considering that frontal cortex has been implicated in semantic processing, a direct connection to this area could signal a fast and automatic access to meaning and would facilitate early semantic influences in visual word recognition. PMID:24038636

  20. Differential effect of age on posterior and anterior hippocampal functional connectivity.

    PubMed

    Damoiseaux, Jessica S; Viviano, Raymond P; Yuan, Peng; Raz, Naftali

    2016-06-01

    Aging is associated with declines in cognitive performance and multiple changes in the brain, including reduced default mode functional connectivity (FC). However, conflicting results have been reported regarding age differences in FC between hippocampal and default mode regions. This discrepancy may stem from the variation in selection of hippocampal regions. We therefore examined the effect of age on resting state FC of anterior and posterior hippocampal regions in an adult life-span sample. Advanced age was associated with lower FC between the posterior hippocampus and three regions: the posterior cingulate cortex, medial prefrontal cortex, and lateral parietal cortex. In addition, age-related reductions of FC between the left and right posterior hippocampus, and bilaterally along the posterior to anterior hippocampal axis were noted. Age differences in medial prefrontal and inter-hemispheric FC significantly differed between anterior and posterior hippocampus. Older age was associated with lower performance in all cognitive domains, but we observed no associations between FC and cognitive performance after controlling for age. We observed a significant effect of gender and a linear effect of COMT val158met polymorphism on hippocampal FC. Females showed higher FC of anterior and posterior hippocampus and medial prefrontal cortex than males, and the dose of val allele was associated with lower posterior hippocampus - posterior cingulate FC, independent of age. Vascular and metabolic factors showed no significant effects on FC. These results suggest differential age-related reduction in the posterior hippocampal FC compared to the anterior hippocampus, and an age-independent effect of gender and COMT on hippocampal FC. PMID:27034025

  1. Effect of inertia variation due to reciprocating parts and connecting rod on coupled free vibration of crankshaft

    SciTech Connect

    Rajendran, S.; Narasimhan, M.V.

    1997-01-01

    The inertia due to reciprocating parts and connected rods, as felt by the crankshaft, varies with the crank angle. The effect of inertia variation on torsional free vibration of crankshafts has been studied extensively. In this paper, the effect on combined torsional and bending free vibrations is examined. Single-cylinder engine crankshaft geometry is considered for the study. The results indicate that the inertial coupling, introduced by the reciprocating parts and connected rod, significantly influences the free vibration characteristics, particularly when the natural frequencies of the crankshaft are closely spaced. The results suggest that, under such conditions, modeling the crankshaft as a pure torsional system would involve considerable error.

  2. Eye movement abnormalities.

    PubMed

    Moncayo, Jorge; Bogousslavsky, Julien

    2012-01-01

    Generation and control of eye movements requires the participation of the cortex, basal ganglia, cerebellum and brainstem. The signals of this complex neural network finally converge on the ocular motoneurons of the brainstem. Infarct or hemorrhage at any level of the oculomotor system (though more frequent in the brain-stem) may give rise to a broad spectrum of eye movement abnormalities (EMAs). Consequently, neurologists and particularly stroke neurologists are routinely confronted with EMAs, some of which may be overlooked in the acute stroke setting and others that, when recognized, may have a high localizing value. The most complex EMAs are due to midbrain stroke. Horizontal gaze disorders, some of them manifesting unusual patterns, may occur in pontine stroke. Distinct varieties of nystagmus occur in cerebellar and medullary stroke. This review summarizes the most representative EMAs from the supratentorial level to the brainstem. PMID:22377853

  3. Effective Models for Electron Tansfer in Proteins - Connection Between Pathway and Detailed Hamiltonians

    NASA Astrophysics Data System (ADS)

    Balabin, I. A.; Onichic, J. N.

    1997-03-01

    Understanding how the protein molecular structure controls the electron transfer (ET) rate is critical for both achieving an insight into vital bioenergetic reactions and designing new ET proteins. We develop and test a new approach for computing ET tunneling matrix elements. Our goal is to provide quantitative results for large molecules with limited computer resources. This connection between simple models and more detailed atomistic models will also provide a better understanding of the basic features that control the ET mechanism. We introduce a series of simple Hamiltonians that incorporate effects of complex molecular structure on the ET rate. Electronic orbital interactions are categorized as classes, and only the most important of them are included. The remaining orbitals are incorporated by means of effective (dependent on the tunneling energy) interaction parameters. Calculations with these Hamiltonians are compared with ``exact'' extended Huckel-level results for several biological and chemically-designed systems. The suggested approach integrates quantum chemical and pathway-like methods. Quantitative calculations with limited computer resources and identification of the domains dominating ET are now in reach. This new developed approach integrates quantum chemistry and pathway-like methods.

  4. Connectivity effects in the segmental self- and cross-reorientation of unentangled polymer melts.

    PubMed

    Ottochian, A; Molin, D; Barbieri, A; Leporini, D

    2009-11-01

    The segmental (bond) rotational dynamics in a polymer melt of unentangled, linear bead-spring chains is studied by molecular dynamics simulations. To single out the connectivity effects, states with limited deviations from the Gaussian behavior of the linear displacement are considered. Both the self and the cross bond-bond correlations with rank [script-l]=1,2 are studied in detail. For [script-l]=1 the correlation functions are precisely described by expressions involving the correlation functions of the chain modes. Several approximations concerning both the self- and the cross-correlations with [script-l]=1,2 are developed and assessed. It is found that the simplified description of the excluded volume static effects derived elsewhere [D. Molin et al., J. Phys.: Condens. Matter 18, 7543 (2006)] well accounts for the short time cross-correlations. It also allows a proper modification of the Rouse theory which provides quantitative account of the intermediate and the long time decay of the rotational correlations with [script-l]=1. PMID:19895041

  5. Resonant Transmission through Serially Connected Hexagonal Nanorings with Magnetic Flux Effects

    NASA Astrophysics Data System (ADS)

    Hedin, Eric; Joe, Yong

    Nanostructures composed of six quantum dots (QDs) connected in a ring are linked together in a linear chain with each ring separated by a coupling segment from adjoining rings. A tight-binding model is used to obtain the electron transmission through an arbitrary number of rings in series as a function of energy, external magnetic field, coupling parameters, and QD site energy values. Modifications of the transmission band structure as a function of external field, due to the Aharonov-Bohm and Zeeman effects, demonstrate control over the conductance properties of the linear chain of nano-rings. Resonant transmission effects (with electron energy equal to the QD site energy values) show a complex dependence upon an interplay of magnetic flux, inter-ring coupling, and the strength of the coupling between the ring system and the external leads. For specific values of lead and ring couplings, nearly full transmission (ballistic transport) is seen to occur across a broad energy range, independent of the number of rings in series. Partially supported by BSU ASPiRE program.

  6. Abnormal Grain Growth Suppression in Aluminum Alloys

    NASA Technical Reports Server (NTRS)

    Hales, Stephen J. (Inventor); Claytor, Harold Dale (Inventor); Alexa, Joel A. (Inventor)

    2015-01-01

    The present invention provides a process for suppressing abnormal grain growth in friction stir welded aluminum alloys by inserting an intermediate annealing treatment ("IAT") after the welding step on the article. The IAT may be followed by a solution heat treatment (SHT) on the article under effectively high solution heat treatment conditions. In at least some embodiments, a deformation step is conducted on the article under effective spin-forming deformation conditions or under effective superplastic deformation conditions. The invention further provides a welded article having suppressed abnormal grain growth, prepared by the process above. Preferably the article is characterized with greater than about 90% reduction in area fraction abnormal grain growth in any friction-stir-welded nugget.

  7. Effect of handedness on brain activity patterns and effective connectivity network during the semantic task of Chinese characters.

    PubMed

    Gao, Qing; Wang, Junping; Yu, Chunshui; Chen, Huafu

    2015-01-01

    Increasing efforts have been denoted to elucidating the effective connectivity (EC) among brain regions recruited by certain language task; however, it remains unclear the impact of handedness on the EC network underlying language processing. In particularly, this has not been investigated in Chinese language, which shows several differences from alphabetic language. This study thereby explored the functional activity patterns and the EC network during a Chinese semantic task based on functional MRI data of healthy left handers (LH) and right handers (RH). We found that RH presented a left lateralized activity pattern in cerebral cortex and a right lateralized pattern in cerebellum; while LH were less lateralized than RH in both cerebral and cerebellar areas. The conditional Granger causality method in deconvolved BOLD level further demonstrated more interhemispheric directional connections in LH than RH group, suggesting better bihemispheric coordination and increased interhemispheric communication in LH. Furthermore, we found significantly increased EC from right middle occipital gyrus to bilateral insula (INS) while decreased EC from left INS to left precentral gyrus in LH group comparing to RH group, implying that handedness may differentiate the causal relationship of information processing in integration of visual-spatial analysis and semantic word retrieval of Chinese characters. PMID:26666706

  8. Effect of handedness on brain activity patterns and effective connectivity network during the semantic task of Chinese characters

    PubMed Central

    Gao, Qing; Wang, Junping; Yu, Chunshui; Chen, Huafu

    2015-01-01

    Increasing efforts have been denoted to elucidating the effective connectivity (EC) among brain regions recruited by certain language task; however, it remains unclear the impact of handedness on the EC network underlying language processing. In particularly, this has not been investigated in Chinese language, which shows several differences from alphabetic language. This study thereby explored the functional activity patterns and the EC network during a Chinese semantic task based on functional MRI data of healthy left handers (LH) and right handers (RH). We found that RH presented a left lateralized activity pattern in cerebral cortex and a right lateralized pattern in cerebellum; while LH were less lateralized than RH in both cerebral and cerebellar areas. The conditional Granger causality method in deconvolved BOLD level further demonstrated more interhemispheric directional connections in LH than RH group, suggesting better bihemispheric coordination and increased interhemispheric communication in LH. Furthermore, we found significantly increased EC from right middle occipital gyrus to bilateral insula (INS) while decreased EC from left INS to left precentral gyrus in LH group comparing to RH group, implying that handedness may differentiate the causal relationship of information processing in integration of visual-spatial analysis and semantic word retrieval of Chinese characters. PMID:26666706

  9. Abnormal Web Usage Control by Proxy Strategies.

    ERIC Educational Resources Information Center

    Yu, Hsiang-Fu; Tseng, Li-Ming

    2002-01-01

    Approaches to designing a proxy server with Web usage control and to making the proxy server effective on local area networks are proposed to prevent abnormal Web access and to prioritize Web usage. A system is implemented to demonstrate the approaches. The implementation reveals that the proposed approaches are effective, such that the abnormal…

  10. Melt Connectivity and Its Effect on Grain Growth in Natural Olivine Aggregates: An Experimental Study

    NASA Astrophysics Data System (ADS)

    Hashim, L.; Sifre, D.; Précigout, J.; Gardés, E.; Le Trong, E.; Gaillard, F.

    2014-12-01

    To better constrain the rheology of the mantle, experimental studies on olivine grain growth have been conducted (Faul and Scott, 2006; Karato, 1989; Nichols and Mackwell, 1991) since the grain size is an important parameter under dynamic regimes (e.g. diffusion creep and grain boundary sliding). In order to better define the melt effect on the rheological response of a partially molten olivine aggregate, we have experimentally investigated the effect of melt on olivine grain growth and the connectivity of this melt phase. Experiments were performed in 3/4" piston cylinders at 500 MPa confining pressure, different temperatures (i.e. 1100°C, 1250°C and 1400°C) and four durations (1h, 12h, 72h and 15 days). Starting material was composed of natural San Carlos olivine (5 μmconnectivity was assessed through scanning electron microscope (SEM) images in backscattered electron mode. Electron backscatter diffraction (EBSD) maps of each sample were also collected in order to determine the olivine grain sizes as a function of time and melt content. References Faul, U. H., Scott, D., 2006. Grain growth in partially molten olivine aggregates. Contributions to Mineralogy and Petrology 151 (1), 101-111. Karato, S.-I., 1989. Grain growth kinetics in olivine aggregates. Tectonophysics 168 (4), 255-273. Nichols, S. J., Mackwell, S. J., 1991. Grain growth in porous olivine aggregates. Physics and Chemistry of Minerals 18 (4), 269-278. Sifré, D., Gardés, E., Massuyeau, M., Hashim, L., Hier-Majumder, S., Gaillard, F., 2014. Electrical conductivity during incipient melting in the oceanic low-velocity zone. Nature 509 (7498), 81-85.

  11. Alterations in Brain Connectivity Underlying Beta Oscillations in Parkinsonism

    PubMed Central

    Moran, Rosalyn J.; Mallet, Nicolas; Litvak, Vladimir; Dolan, Raymond J.; Magill, Peter J.; Friston, Karl J.; Brown, Peter

    2011-01-01

    Cortico-basal ganglia-thalamocortical circuits are severely disrupted by the dopamine depletion of Parkinson's disease (PD), leading to pathologically exaggerated beta oscillations. Abnormal rhythms, found in several circuit nodes are correlated with movement impairments but their neural basis remains unclear. Here, we used dynamic causal modelling (DCM) and the 6-hydroxydopamine-lesioned rat model of PD to examine the effective connectivity underlying these spectral abnormalities. We acquired auto-spectral and cross-spectral measures of beta oscillations (10–35 Hz) from local field potential recordings made simultaneously in the frontal cortex, striatum, external globus pallidus (GPe) and subthalamic nucleus (STN), and used these data to optimise neurobiologically plausible models. Chronic dopamine depletion reorganised the cortico-basal ganglia-thalamocortical circuit, with increased effective connectivity in the pathway from cortex to STN and decreased connectivity from STN to GPe. Moreover, a contribution analysis of the Parkinsonian circuit distinguished between pathogenic and compensatory processes and revealed how effective connectivity along the indirect pathway acquired a strategic importance that underpins beta oscillations. In modelling excessive beta synchrony in PD, these findings provide a novel perspective on how altered connectivity in basal ganglia-thalamocortical circuits reflects a balance between pathogenesis and compensation, and predicts potential new therapeutic targets to overcome dysfunctional oscillations. PMID:21852943

  12. Effect of trichostatin A on human T cells resembles signaling abnormalities in T cells of patients with systemic lupus erythematosus: a new mechanism for TCR zeta chain deficiency and abnormal signaling.

    PubMed

    Nambiar, Madhusoodana P; Warke, Vishal G; Fisher, Carolyn U; Tsokos, George C

    2002-01-01

    Trichostatin A (TSA) is a potent reversible inhibitor of histone deacetylase, and it has been reported to have variable effects on the expression of a number of genes. In this report, we show that TSA suppresses the expression of the T cell receptor zeta chain gene, whereas, it upregulates the expression if its homologous gene Fc(epsilon) receptor I gamma chain. These effects are associated with decreased intracytoplasmic-free calcium responses and altered tyrosine phosphorylation pattern of cytosolic proteins. Along with these effects, we report that TSA suppresses the expression of the interleukin-2 gene. The effects of TSA on human T cells are predominantly immunosuppressive and reminiscent of the signaling aberrations that have been described in patients with systemic lupus erythematosus. PMID:11967985

  13. What proportion of congenital abnormalities can be prevented?

    PubMed Central

    Czeizel, A E; Intôdy, Z; Modell, B

    1993-01-01

    OBJECTIVE--To estimate the proportion of preventable congenital abnormalities in Hungary. DESIGN--Analysis of available Hungarian data-bases and of the effectiveness of primary, secondary, and tertiary preventive methods. SETTING--Databases of ad hoc epidemiological studies and of the Hungarian congenital abnormality registry. MAIN OUTCOME MEASURES--Prevalence at birth and prevalence after prevention in 73 congenital abnormality types or groups. RESULTS--Preventive methods are available for 51 (70%) of the 73 congenital abnormality types or groups evaluated. The birth prevalence of all congenital abnormalities could be reduced from 65 to 26 per 1000; thus 39 per 1000 (60%) are preventable. Without congenital dislocation of the hip, which is unusually common in Hungary, the preventable proportion of congenital abnormalities is 52%. CONCLUSION--Many congenital abnormalities can be prevented, but as they do not represent a single pathological category there is no single strategy for their prevention. Images p502-a p503-a PMID:8448464

  14. Effects of interleukins on connective tissue type mast cells co-cultured with fibroblasts.

    PubMed Central

    Levi-Schaffer, F; Segal, V; Shalit, M

    1991-01-01

    We investigated the effects of interleukin-2 (IL-2), interleukin-3 (IL-3) and interleukin-4 (IL-4) on mouse and rat peritoneal mast cells (MC) co-cultured with 3T3 fibroblasts (MC/3T3). The continuous presence of these cytokines for 7-9 days in the culture media was neither toxic nor caused proliferation of MC, as determined by the stability of MC numbers in culture. Long-term incubation of mouse MC/3T3 with IL-2 (100 U/ml), IL-3 (50 U/ml), IL-4 (50 U/ml) or a mixture of IL-3 and IL-4 (25 U/ml) induced an increase in basal histamine release of 79.3 +/- 19.0%, 41.0 +/- 17.3%, 25.2 +/- 10.4% and 30.2 +/- 3.2%, respectively, over control cells incubated with medium alone. When rat MC/3T3 were incubated for 7 days with the various interleukins an enhancement in histamine release similar to that observed with mouse MC/3T3 was found. Preincubation (1 hr) of rat MC/3T3 with interleukins prior to immunological activation with anti-IgE antibodies enhanced histamine release. The highest effect was observed with IL-3 + IL-4 (60.4 +/- 10.8% increase) followed by IL-2 (51.5 +/- 4.5%), IL-4 (28.6 +/- 10.3%) and IL-3 (13.2 +/- 4.2%). This study demonstrates that when mouse and rat peritoneal MC are cultured with fibroblasts in the presence of interleukins they do not proliferate, suggesting that they preserve their connective tissue type MC phenotype. Moreover, interleukins display a pro-inflammatory effect on these cells by enhancing both basal and anti-IgE-mediated histamine release. PMID:2016117

  15. Activity and High-Order Effective Connectivity Alterations in Sanfilippo C Patient-Specific Neuronal Networks

    PubMed Central

    Canals, Isaac; Soriano, Jordi; Orlandi, Javier G.; Torrent, Roger; Richaud-Patin, Yvonne; Jiménez-Delgado, Senda; Merlin, Simone; Follenzi, Antonia; Consiglio, Antonella; Vilageliu, Lluïsa; Grinberg, Daniel; Raya, Angel

    2015-01-01

    Summary Induced pluripotent stem cell (iPSC) technology has been successfully used to recapitulate phenotypic traits of several human diseases in vitro. Patient-specific iPSC-based disease models are also expected to reveal early functional phenotypes, although this remains to be proved. Here, we generated iPSC lines from two patients with Sanfilippo type C syndrome, a lysosomal storage disorder with inheritable progressive neurodegeneration. Mature neurons obtained from patient-specific iPSC lines recapitulated the main known phenotypes of the disease, not present in genetically corrected patient-specific iPSC-derived cultures. Moreover, neuronal networks organized in vitro from mature patient-derived neurons showed early defects in neuronal activity, network-wide degradation, and altered effective connectivity. Our findings establish the importance of iPSC-based technology to identify early functional phenotypes, which can in turn shed light on the pathological mechanisms occurring in Sanfilippo syndrome. This technology also has the potential to provide valuable readouts to screen compounds, which can prevent the onset of neurodegeneration. PMID:26411903

  16. Hydrogeomorphic connectivity on roads crossing in rural headwaters and its effect on stream dynamics.

    PubMed

    Thomaz, Edivaldo L; Peretto, Gustavo T

    2016-04-15

    Unpaved roads are ubiquitous features that have been transforming the landscape through human history. Unpaved roads affect the water and sediment pathways through a catchment and impacts the aquatic ecosystem. In this study, we describe the effect of unpaved road on the hydrogeomorphic connectivity at the rural headwater scale. Measurement was based on the stream crossing approach, i.e., road superimposing the drainage system. We installed a Parshall flume coupled with single-stage suspended sediment sampler at each stream crossing. In addition, we displayed our monitoring scheme with an upscaling perspective from second-order to third-order stream. We concluded that the road-stream coupling dramatically changed the stream dynamic. The increase of discharge caused by roads at the headwater was 50% larger compared to unaffected streams. Additionally, suspended sediment concentration enhancement at stream crossings ranged from to 413% at second-order streams to 145% at third-order streams. The landform characteristics associated with the road network produced an important hydrogeomorphic disruption in the landscape. As a result, the sediment filter function of the riparian zone was reduced dramatically. Therefore, we recommend that projects for aquatic system restoration or conservation in rural landscape consider the role of the road network on stream dynamics. PMID:26849320

  17. Evaluating the effective connectivity of resting state networks using conditional Granger causality.

    PubMed

    Liao, Wei; Mantini, Dante; Zhang, Zhiqiang; Pan, Zhengyong; Ding, Jurong; Gong, Qiyong; Yang, Yihong; Chen, Huafu

    2010-01-01

    The human brain has been documented to be spatially organized in a finite set of specific coherent patterns, namely resting state networks (RSNs). The interactions among RSNs, being potentially dynamic and directional, may not be adequately captured by simple correlation or anticorrelation. In order to evaluate the possible effective connectivity within those RSNs, we applied a conditional Granger causality analysis (CGCA) to the RSNs retrieved by independent component analysis (ICA) from resting state functional magnetic resonance imaging (fMRI) data. Our analysis provided evidence for specific causal influences among the detected RSNs: default-mode, dorsal attention, core, central-executive, self-referential, somatosensory, visual, and auditory networks. In particular, we identified that self-referential and default-mode networks (DMNs) play distinct and crucial roles in the human brain functional architecture. Specifically, the former RSN exerted the strongest causal influence over the other RSNs, revealing a top-down modulation of self-referential mental activity (SRN) over sensory and cognitive processing. In quite contrast, the latter RSN was profoundly affected by the other RSNs, which may underlie an integration of information from primary function and higher level cognition networks, consistent with previous task-related studies. Overall, our results revealed the causal influences among these RSNs at different processing levels, and supplied information for a deeper understanding of the brain network dynamics. PMID:19937337

  18. Changes in Effective Connectivity of the Superior Parietal Lobe during Inhibition and Redirection of Eye Movements

    PubMed Central

    Asscheman, Susanne J.; Thakkar, Katharine N.; Neggers, Sebastiaan F.W.

    2015-01-01

    Executive control is the ability to flexibly control behavior and is frequently studied with saccadic eye movements. Contrary to frontal oculomotor areas, the role of the superior parietal lobe (SPL) in the executive control of saccades remains unknown. To explore the role of SPL networks in saccade control, we performed a saccadic search-step task while acquiring functional magnetic resonance imaging data for 41 participants. Psychophysiological interaction analyses assessed task-related differences in the effective connectivity of SPL with other brain regions during the inhibition and redirection of saccades. Results indicate an increased coupling of SPL with frontal, posterior, and striatal oculomotor areas for redirected saccades versus visually guided saccades. Saccade inhibition versus unsuccessful inhibition revealed an increased coupling of SPL with dorsolateral prefrontal cortex and anterior cingulate cortex. We discuss how these findings relate to ongoing debates about the implementation of executive control and conclude that early attentional control and rapid updating of saccade goals are important signals for executive control. PMID:27147827

  19. Recursive reminding: effects of repetition, printed frequency, connectivity, and set size on recognition and judgments of frequency.

    PubMed

    Fisher, Serena L; Nelson, Douglas L

    2006-03-01

    In the present experiments, predictions of common path and recursive-reminding models of recognition (RG) and judgments of frequency (JOFs) were contrasted. The results indicated that each task is affected by study frequency, printed frequency, and associative connectivity. However, effect size analyses indicated that study frequency and item attributes show a double dissociation over tasks. Study frequency has a greater effect on JOFs than on RG, whereas printed frequency and associative connectivity have greater effects on RG than on JOFs. The recursive-reminding model predicts differential effects of study frequency, because it assumes that although both tasks are influenced by familiarity, JOF is more likely to be affected by recollective reminding as a procedure for encoding event frequency. Associative set size effects were absent in each task, suggesting that competitors play no role in either task. PMID:16752594

  20. Effects of ostracism and social connection-related activities on adolescents’ motivation to eat and energy intake

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Objective: assess the effect of ostracism and social connection-related activities on adolescents’ motivation to eat and their energy intake. Methods Participants (n¼103; M age¼13.6 years) were either ostracized or included when playing a computer game, Cyberball. Next, they wrote about their friend...

  1. 26 CFR 1.882-2 - Income of foreign corporations treated as effectively connected with U.S. business.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 9 2010-04-01 2010-04-01 false Income of foreign corporations treated as... Income of foreign corporations treated as effectively connected with U.S. business. (a) Election as to... property, may elect, pursuant to section 882(d) and § 1.871-10, to treat all such income as income which...

  2. Effects of School-Based Interventions with U.S. Military-Connected Children: A Systematic Review

    ERIC Educational Resources Information Center

    Brendel, Kristen Esposito; Maynard, Brandy R.; Albright, David L.; Bellomo, Mary

    2014-01-01

    Objective: To examine the effects of school-based interventions on the well-being of military-connected children (i.e., dependents of U.S. military service members, veterans, or reserve component members) who attend public or private elementary or secondary schools with parental deployment, parental reintegration, parental military-related trauma…

  3. Reorganization of Functional and Effective Connectivity during Real-Time fMRI-BCI Modulation of Prosody Processing

    ERIC Educational Resources Information Center

    Rota, Giuseppina; Handjaras, Giacomo; Sitaram, Ranganatha; Birbaumer, Niels; Dogil, Grzegorz

    2011-01-01

    Mechanisms of cortical reorganization underlying the enhancement of speech processing have been poorly investigated. In the present study, we addressed changes in functional and effective connectivity induced in subjects who learned to deliberately increase activation in the right inferior frontal gyrus (rIFG), and improved their ability to…

  4. 26 CFR 1.882-2 - Income of foreign corporations treated as effectively connected with U.S. business.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 9 2014-04-01 2014-04-01 false Income of foreign corporations treated as effectively connected with U.S. business. 1.882-2 Section 1.882-2 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES (CONTINUED) Foreign Corporations § 1.882-2 Income of...

  5. Connectivity and effects of streams and wetlands on downstream waters: A review and synthesis of the sientific evidence 2302

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The purpose of this document is to review and synthesize more than 850 publications from the peer-reviewed literature pertaining to three questions: 1) What are the physical, chemical, and biological connections to and effects of ephemeral, intermittent, and perennial streams on downstream waters? 2...

  6. Relative Effects of Road Risk, Habitat Suitability, and Connectivity on Wildlife Roadkills: The Case of Tawny Owls (Strix aluco)

    PubMed Central

    Santos, Sara M.; Lourenço, Rui; Mira, António; Beja, Pedro

    2013-01-01

    Background Despite its importance for reducing wildlife-vehicle collisions, there is still incomplete understanding of factors responsible for high road mortality. In particular, few empirical studies examined the idea that spatial variation in roadkills is influenced by a complex interplay between road-related factors, and species-specific habitat quality and landscape connectivity. Methodology/Principal Findings In this study we addressed this issue, using a 7-year dataset of tawny owl (Strix aluco) roadkills recorded along 37 km of road in southern Portugal. We used a multi-species roadkill index as a surrogate of intrinsic road risk, and we used a Maxent distribution model to estimate habitat suitability. Landscape connectivity was estimated from least-cost paths between tawny owl territories, using habitat suitability as a resistance surface. We defined 10 alternative scenarios to compute connectivity, based on variation in potential movement patterns according to territory quality and dispersal distance thresholds. Hierarchical partitioning of a regression model indicated that independent variation in tawny owl roadkills was explained primarily by the roadkill index (70.5%) and, to a much lesser extent, by landscape connectivity (26.2%), while habitat suitability had minor effects (3.3%). Analysis of connectivity scenarios suggested that owl roadkills were primarily related to short range movements (<5 km) between high quality territories. Tawny owl roadkills were spatially autocorrelated, but the introduction of spatial filters in the regression model did not change the type and relative contribution of environmental variables. Conclusions Overall, results suggest that road-related factors may have a dominant influence on roadkill patterns, particularly in areas like ours where habitat quality and landscape connectivity are globally high for the study species. Nevertheless, the study supported the view that functional connectivity should be incorporated

  7. Effects of Dynamic Strain Hardening Exponent on Abnormal Cleavage Fracture Occurring During Drop Weight Tear Test of API X70 and X80 Linepipe Steels

    NASA Astrophysics Data System (ADS)

    Kang, Minju; Kim, Hyunmin; Lee, Sunghak; Shin, Sang Yong

    2014-02-01

    In this study, drop weight tear tests (DWTT) were conducted on API X70 and X80 linepipe steels fabricated with various compositions and rolling and cooling conditions in order to correlate the strain hardening with the abnormal cleavage fracture occurring in the hammer-impacted area. Area fractions of fracture modes were measured from fractured DWTT specimens, and the measured data were analyzed in relation to microstructures, Charpy impact energy, and strain hardening. All the steels consisted of fine acicular ferrite, together with some bainitic ferrite, granular bainite, and martensite-austenite constituent. As the volume fraction of acicular ferrite increased, the area fraction of DWTT abnormal cleavage fracture decreased because the toughness of acicular ferrite was higher than other microstructures. The area fraction of abnormal cleavage fracture was weakly related with strain hardening exponents obtained from the quasi-static tensile and compressive tests, but showed better correlation with those obtained from the dynamic compressive test. This tendency could be more clearly observed when steels having similar Charpy impact energy levels were grouped. Since the DWTT was performed under a dynamic loading condition, thus, the abnormal cleavage fracture behavior should be related with the strain hardening analyzed under a dynamic loading condition.

  8. Abnormal uterine bleeding.

    PubMed

    Whitaker, Lucy; Critchley, Hilary O D

    2016-07-01

    Abnormal uterine bleeding (AUB) is a common and debilitating condition with high direct and indirect costs. AUB frequently co-exists with fibroids, but the relationship between the two remains incompletely understood and in many women the identification of fibroids may be incidental to a menstrual bleeding complaint. A structured approach for establishing the cause using the Fédération International de Gynécologie et d'Obstétrique (FIGO) PALM-COEIN (Polyp, Adenomyosis, Leiomyoma, Malignancy (and hyperplasia), Coagulopathy, Ovulatory disorders, Endometrial, Iatrogenic and Not otherwise classified) classification system will facilitate accurate diagnosis and inform treatment options. Office hysteroscopy and increasing sophisticated imaging will assist provision of robust evidence for the underlying cause. Increased availability of medical options has expanded the choice for women and many will no longer need to recourse to potentially complicated surgery. Treatment must remain individualised and encompass the impact of pressure symptoms, desire for retention of fertility and contraceptive needs, as well as address the management of AUB in order to achieve improved quality of life. PMID:26803558

  9. Effect of Flow Pulsatility on Modeling the Hemodynamics in the Total Cavopulmonary Connection

    PubMed Central

    khiabani, Reza H.; Restrepo, Maria; Tang, Elaine; De Zélicourt, Diane; Sotiropoulos, Fotis; Fogel, Mark; Yoganathan, Ajit P.

    2012-01-01

    Total Cavopulmonary Connection is the result of a series of palliative surgical repairs performed on patients with single ventricle heart defects. The resulting anatomy has complex and unsteady hemodynamics characterized by flow mixing and flow separation. Although varying degrees of flow pulsatility have been observed in vivo, non-pulsatile (time-averaged) boundary conditions have traditionally been assumed in hemodynamic modeling, and only recently have pulsatile conditions been incorporated without completely characterizing their effect or importance. In this study, 3D numerical simulations with both pulsatile and non-pulsatile boundary conditions were performed for 24 patients with different anatomies and flow boundary conditions from Georgia Tech database. Flow structures, energy dissipation rates and pressure drops were compared under rest and simulated exercise conditions. It was found that flow pulsatility is the primary factor in determining the appropriate choice of boundary conditions, whereas the anatomic configuration and cardiac output had secondary effects. Results show that the hemodynamics can be strongly influenced by the presence of pulsatile flow. However, there was a minimum pulsatility threshold, identified by defining a weighted pulsatility index (wPI), above which the influence was significant. It was shown that when wPI < 30%, the relative error in hemodynamic predictions using time-averaged boundary conditions was less than 10% compared to pulsatile simulations. In addition, when wPI <50, the relative error was less than 20%. A correlation was introduced to relate wPI to the relative error in predicting the flow metrics with non-pulsatile flow conditions. PMID:22841650

  10. Effects of landiolol on refractory tachyarrhythmia after total cavopulmonary connection: a retrospective, observational, cohort study.

    PubMed

    Miyake, Kentaro; Fujita, Yoshihito; Yoshizawa, Saya; Tomita, Maiko; Miyazu, Mitsunori; Sento, Yoshiki; Yoshimura, Shinichiro; Sobue, Kazuya

    2016-04-01

    The onset of tachyarrhythmia after the Fontan procedure (total cavopulmonary connection; TCPC) should be considered a medical emergency. Landiolol is an ultra-short-acting β1-selective blocker whose effect on tachyarrhythmia after TCPC is unclear. We evaluated the efficacy and safety of landiolol for tachyarrhythmia after TCPC. Consecutive patients undergoing TCPC were enrolled from January 2007 to December 2011. Of 435 pediatric open heart surgeries, 28 patients underwent TCPC. Of the 28 patients, 13 were treated with landiolol for critical tachyarrhythmia. Excluding three patients who received landiolol during surgery, we investigated the remaining 10 patients and statistical analysis was performed without a 10-year-old patient as outlier. The median age was 4.08 years. The subjects comprised five patients with sinus tachycardia, four with junctional ectopic tachycardia and one with paroxysmal supraventricular tachycardia. The initial dose was 4.7 ± 2.3 μg/kg/min, without a loading dose. Landiolol reduced the heart rate from 151.8 ± 23.2 at the start to 132.9 ± 20.0 at 1 h and 126.1 ± 24.9 at 2 h (P < 0.01 and P < 0.01, respectively), without blood pressure decrease (P = 0.235). Landiolol was effective in treating critical tachyarrhythmia without hemodynamic deterioration. We believe that landiolol is a promising option for postoperative tachyarrhythmia after the Fontan procedure. PMID:26699148

  11. The effect of different implant-abutment connections on screw joint stability.

    PubMed

    Michalakis, Konstantinos X; Calvani, Pasquale Lino; Muftu, Sinan; Pissiotis, Argiris; Hirayama, Hiroshi

    2014-04-01

    Dental implants with an internal connection have been designed to establish a better stress distribution when lateral external forces act on the prosthesis and minimize the forces transmitted to the fastening screw. In the present study, 10 externally and 10 internally hexed implants were tested with a compressive force applied with an Instron Universal machine. Four cycles of loading-unloading were applied to each specimen to achieve displacements of 0.5, 1, 2, and 2.5 mm. The mean loads for the first cycle were 256.70 N for the external connection and 256 N for the internal connection implants. The independent t test did not reveal any significant differences among the 2 tested groups (P = .780). For the second cycle, the mean loads needed for a displacement of 1 mm were 818.19 N and 780.20 N for the external connection and the internal connection implants, respectively. The independent t test revealed significant differences among the 2 tested groups (P < .001). In the third cycle, the mean load values for a 2-mm displacement were 1394.10 N and 1225.00 N. The independent t test revealed significant differences among the 2 tested groups (P < .001). The mean loads for the fourth cycle were 1488.00 N for the external connection and 1029.00 N for the internal connection implants. These loads were required for a displacement of 2.5 mm. The independent t test revealed significant differences among the 2 tested groups (P < .001). The results of this in vitro study suggest that the internal connection design of the examined implant system could not prevent screw loosening during overloading. No implant or prosthesis failure was noticed in either group. PMID:24779947

  12. Subjective Effects of Ethanol, Morphine, Δ(9)-Tetrahydrocannabinol, and Ketamine Following a Pharmacological Challenge Are Related to Functional Brain Connectivity.

    PubMed

    Kleinloog, Daniël; Rombouts, Serge; Zoethout, Remco; Klumpers, Linda; Niesters, Marieke; Khalili-Mahani, Najmeh; Dahan, Albert; van Gerven, Joop

    2015-12-01

    This analysis examines the neuronal foundation of drug-induced psychomimetic symptoms by relating the severity of these symptoms to changes in functional connectivity for a range of different psychoactive compounds with varying degrees of psychomimetic effects. The repeated measures design included 323 resting-state functional magnetic resonance imaging time series and measures of subjective effects in 36 healthy male volunteers. Four different pharmacological challenges with ethanol, morphine, Δ(9)-tetrahydrocannabinol, and ketamine (12 subjects per drug) were applied. A set of 10 "template" resting-state networks was used to determine individual connectivity maps. Linear regression was used for each individual subject to relate these connectivity maps to three clusters of drug-induced subjective psychomimetic effects ("perception," "relaxation," and "dysphoria") as measured with visual analogue scales. Group analysis showed that the subjective effects of perception correlated significantly across drugs with the connectivity of the posterior cingulate cortex and precentral gyrus with the sensorimotor network (p < 0.005, corrected). No significant correlations were found for relaxation or dysphoria. The posterior cingulate cortex has a role in visuospatial evaluation and the precentral gyrus has been associated with auditory hallucinations. Both the posterior cingulate cortex and the precentral gyrus show changes in activation in patients with schizophrenia, which can be related to the severity of positive symptoms (i.e., hallucinations and delusions), and have previously been related to changes induced by psychoactive drugs. The similarity of functional connectivity changes for drug-induced psychomimetic effects and symptoms of psychosis provides further support for the use of pharmacological challenges with psychomimetic drugs as models for psychosis. PMID:26390148

  13. Effect of implant connection and restoration design (screwed vs. cemented) in reliability and failure modes of anterior crowns.

    PubMed

    Freitas, Amilcar C; Bonfante, Estevam A; Rocha, Eduardo P; Silva, Nelson R F A; Marotta, Leonard; Coelho, Paulo G

    2011-08-01

    The mechanical performance of cemented or screw-retained implant-supported crowns with an internal or external configuration is yet to be understood. This in vitro study evaluated the effect of screw-retained and cement-retained prostheses on internal and external implant-abutment connections. Thereby, the reliability and failure modes of crowns were investigated. Eighty-four implants (Emfils; Colosso Evolution system) were divided into four groups (n=21 each): screw-retained and internal connection (Si), screw-retained and external connection (Se), cement-retained and internal connection (Ci), and cement-retained and external connection (Ce). Ti-6Al-4V abutments were torqued (30 Ncm) to the implants, and maxillary central incisor metal crowns were torqued (30 Ncm) or cemented (Rely X Unicem; 3M-ESPE) and subjected to accelerated life-testing in water. Use-level probability Weibull curves and reliability for 50,000 cycles at 150 N were calculated. The β values for Si (1.72), Se (1.50), Ci (1.34), and Ce (1.77) groups indicated that fatigue/damage accumulation accelerated their failure. The Ci group presented the highest reliability, the Se group presented the lowest reliability, and Si and Ce groups presented intermediate reliability. Screw-retained restorations presented mainly abutment fracture. Cement-retained restorations resulted in failures of the screw in the Ce group, but implant/screw fracture in the Ci group. PMID:21726295

  14. The effects of age on resting state functional connectivity of the basal ganglia from young to middle adulthood.

    PubMed

    Manza, Peter; Zhang, Sheng; Hu, Sien; Chao, Herta H; Leung, Hoi-Chung; Li, Chiang-shan R

    2015-02-15

    The basal ganglia nuclei are critical for a variety of cognitive and motor functions. Much work has shown age-related structural changes of the basal ganglia. Yet less is known about how the functional interactions of these regions with the cerebral cortex and the cerebellum change throughout the lifespan. Here, we took advantage of a convenient sample and examined resting state functional magnetic resonance imaging data from 250 adults 18 to 49 years of age, focusing specifically on the caudate nucleus, pallidum, putamen, and ventral tegmental area/substantia nigra (VTA/SN). There are a few main findings to report. First, with age, caudate head connectivity increased with a large region of ventromedial prefrontal/medial orbitofrontal cortex. Second, across all subjects, pallidum and putamen showed negative connectivity with default mode network (DMN) regions such as the ventromedial prefrontal cortex and posterior cingulate cortex, in support of anti-correlation of the "task-positive" network (TPN) and DMN. This negative connectivity was reduced with age. Furthermore, pallidum, posterior putamen and VTA/SN connectivity to other TPN regions, such as somatomotor cortex, decreased with age. These results highlight a distinct effect of age on cerebral functional connectivity of the dorsal striatum and VTA/SN from young to middle adulthood and may help research investigating the etiologies or monitoring outcomes of neuropsychiatric conditions that implicate dopaminergic dysfunction. PMID:25514518

  15. Pervasive microstructural abnormalities in autism: a DTI study

    PubMed Central

    Groen, Wouter B.; Buitelaar, Jan K.; van der Gaag, Rutger J.; Zwiers, Marcel P.

    2011-01-01

    Background Recent studies have reported abnormal functional connectivity patterns in the brains of people with autism that may be accompanied by decreases in white matter integrity. Since autism is a developmental disorder, we aim to investigate the nature and location of decreases in white and grey matter integrity in an adolescent sample while accounting for age. Methods We used structural (T1) imaging to study brain volumetrics and diffusion tensor imaging (DTI) to investigate white and grey matter integrity in people with autism. We obtained magnetic resonance images for adolescents aged 12–18 years with high-functioning autism and from matched controls. Fractional anisotropy and mean diffusivity, as well as grey and white matter volumetrics were analyzed. Results There were 17 participants with autism and 25 matched controls included in this study. Participants with autism had lower fractional anisotropy in the left and right superior and inferior longitudinal fasciculus, but this effect was not significant after adjusting for age and intelligence quotient (IQ). The kurtosis of the white matter fractional anisotropy probability distribution was higher in this participant group, with and without adjustment for age and IQ. Most notably, however, the mean diffusivity levels were markedly increased in the autism group throughout the brain, and the mean diffusivity probability distributions of both grey and white matter were shifted toward a higher value, particularly with age and IQ adjustment. No volumetric differences in grey and white matter were found. Limitations We corrected for age and IQ using a linear model. The study was also limited by its sample size, investigated age range and cross-sectional design. Conclusion The findings suggest that autism is characterized by a generalized reduction of white matter integrity that is associated with an increase of interstitial space. The generalized manifestation of the white matter abnormalities provides an

  16. Identifying effective connectivity parameters in simulated fMRI: a direct comparison of switching linear dynamic system, stochastic dynamic causal, and multivariate autoregressive models

    PubMed Central

    Smith, Jason F.; Chen, Kewei; Pillai, Ajay S.; Horwitz, Barry

    2013-01-01

    The number and variety of connectivity estimation methods is likely to continue to grow over the coming decade. Comparisons between methods are necessary to prune this growth to only the most accurate and robust methods. However, the nature of connectivity is elusive with different methods potentially attempting to identify different aspects of connectivity. Commonalities of connectivity definitions across methods upon which base direct comparisons can be difficult to derive. Here, we explicitly define “effective connectivity” using a common set of observation and state equations that are appropriate for three connectivity methods: dynamic causal modeling (DCM), multivariate autoregressive modeling (MAR), and switching linear dynamic systems for fMRI (sLDSf). In addition while deriving this set, we show how many other popular functional and effective connectivity methods are actually simplifications of these equations. We discuss implications of these connections for the practice of using one method to simulate data for another method. After mathematically connecting the three effective connectivity methods, simulated fMRI data with varying numbers of regions and task conditions is generated from the common equation. This simulated data explicitly contains the type of the connectivity that the three models were intended to identify. Each method is applied to the simulated data sets and the accuracy of parameter identification is analyzed. All methods perform above chance levels at identifying correct connectivity parameters. The sLDSf method was superior in parameter estimation accuracy to both DCM and MAR for all types of comparisons. PMID:23717258

  17. Causal relationship between effective connectivity within the default mode network and mind-wandering regulation and facilitation.

    PubMed

    Kajimura, Shogo; Kochiyama, Takanori; Nakai, Ryusuke; Abe, Nobuhito; Nomura, Michio

    2016-06-01

    Transcranial direct current stimulation (tDCS) can modulate mind wandering, which is a shift in the contents of thought away from an ongoing task and/or from events in the external environment to self-generated thoughts and feelings. Although modulation of the mind-wandering propensity is thought to be associated with neural alterations of the lateral prefrontal cortex (LPFC) and regions in the default mode network (DMN), the precise neural mechanisms remain unknown. Using functional magnetic resonance imaging (fMRI), we investigated the causal relationships among tDCS (one electrode placed over the right IPL, which is a core region of the DMN, and another placed over the left LPFC), stimulation-induced directed connection alterations within the DMN, and modulation of the mind-wandering propensity. At the behavioral level, anodal tDCS on the right IPL (with cathodal tDCS on the left LPFC) reduced mind wandering compared to the reversed stimulation. At the neural level, the anodal tDCS on the right IPL decreased the afferent connections of the posterior cingulate cortex (PCC) from the right IPL and the medial prefrontal cortex (mPFC). Furthermore, mediation analysis revealed that the changes in the connections from the right IPL and mPFC correlated with the facilitation and inhibition of mind wandering, respectively. These effects are the result of the heterogeneous function of effective connectivity: the connection from the right IPL to the PCC inhibits mind wandering, whereas the connection from the mPFC to the PCC facilitates mind wandering. The present study is the first to demonstrate the neural mechanisms underlying tDCS modulation of mind-wandering propensity. PMID:26975555

  18. Connected Traveler

    SciTech Connect

    Schroeder, Alex

    2015-11-01

    The Connected Traveler project is a multi-disciplinary undertaking that seeks to validate potential for transformative transportation system energy savings by incentivizing efficient traveler behavior. This poster outlines various aspects of the Connected Traveler project, including market opportunity, understanding traveler behavior and decision-making, automation and connectivity, and a projected timeline for Connected Traveler's key milestones.

  19. Evaluating the Effectiveness of the 1998-1999 NASA CONNECT Program

    NASA Technical Reports Server (NTRS)

    Pinelli, Thomas E.; Frank, Kari Lou; House, Patricia L.

    2000-01-01

    NASA CONNECT is a standards-based, integrated mathematics, science, and technology series of 30-minute instructional distance learning (satellite and television) programs for students in grades 5-8. Each of the five programs in the 1998-1999 NASA CONNECT series included a lesson, an educator guide, a student activity or experiment, and a web-based component. In March 1999, a mail (self-reported) survey (booklet) was sent to a randomly selected sample of 1,000 NASA CONNECT registrants. A total of 401 surveys (351 usable) were received by the established cut-off date. Most survey questions employed a 5-point Likert-type response scale. Survey topics included: (1) instructional technology and teaching, (2) instructional programming and technology in the classroom, (3) the NASA CONNECT program, (4) classroom use of computer technology, and (5) demographics. About 68% of the respondents were female, about 88% identified "classroom teacher" as their present professional duty, about 75% worked in a public school, and about 67% held a master's degree or master's equivalency. Regarding NASA CONNECT, respondents reported that: (1) they used the five programs in the 1998-1999 NASA CONNECT series; (2) the stated objectives for each program were met (4.49); (3) the programs were aligned with the national mathematics, science, and technology standards (4.61); (4) program content was developmentally appropriate for grade level (4.25); and (5) the programs in the 1998-1999 NASA CONNECT series enhanced/enriched the teaching of mathematics, science, and technology (4.45).

  20. Evaluating the Effectiveness of the 1999-2000 NASA CONNECT Program

    NASA Technical Reports Server (NTRS)

    Pinelli, Thomas E.; Frank, Kari Lou

    2002-01-01

    NASA CONNECT is a standards-based, integrated mathematics, science, and technology series of 30-minute instructional distance learning (satellite and television) programs for students in grades 6-8. Each of the five programs in the 1999-2000 NASA CONNECT series included a lesson, an educator guide, a student activity or experiment, and a web-based component. In March 2000, a mail (self-reported) survey (booklet) was sent to a randomly selected sample of 1,000 NASA CONNECT registrants. A total of 336 surveys (269 usable) were received by the established cut-off date. Most survey questions employed a 5-point Likert-type response scale. Survey topics included (1) instructional technology and teaching, (2) instructional programming and technology in the classroom, (3) the NASA CONNECT program, (4) classroom use of computer technology, and (5) demographics. About 73% of the respondents were female, about 92% identified "classroom teacher" as their present professional duty, about 90% worked in a public school, and about 62% held a master's degree or master's equivalency. Regarding NASA CONNECT, respondents reported that (1) they used the five programs in the 1999-2000 NASA CONNECT series; (2) the stated objectives for each program were met (4.54); (3) the programs were aligned with the national mathematics, science, and technology standards (4.57); (4) program content was developmentally appropriate for grade level (4.17); and (5) the programs in the 1999-2000 NASA CONNECT series enhanced/enriched the teaching of mathematics, science, and technology (4.51).

  1. Advances in understanding paternally transmitted Chromosomal Abnormalities

    SciTech Connect

    Marchetti, F; Sloter, E; Wyrobek, A J

    2001-03-01

    Multicolor FISH has been adapted for detecting the major types of chromosomal abnormalities in human sperm including aneuploidies for clinically-relevant chromosomes, chromosomal aberrations including breaks and rearrangements, and other numerical abnormalities. The various sperm FISH assays have been used to evaluate healthy men, men of advanced age, and men who have received mutagenic cancer therapy. The mouse has also been used as a model to investigate the mechanism of paternally transmitted genetic damage. Sperm FISH for the mouse has been used to detect chromosomally abnormal mouse sperm, while the PAINT/DAPI analysis of mouse zygotes has been used to evaluate the types of chromosomal defects that can be paternally transmitted to the embryo and their effects on embryonic development.

  2. The effects of dexamphetamine on the resting-state electroencephalogram and functional connectivity.

    PubMed

    Albrecht, Matthew A; Roberts, Gareth; Price, Greg; Lee, Joseph; Iyyalol, Rajan; Martin-Iverson, Mathew T

    2016-02-01

    The catecholamines-dopamine and noradrenaline-play important roles in directing and guiding behavior. Disorders of these systems, particularly within the dopamine system, are associated with several severe and chronically disabling psychiatric and neurological disorders. We used the recently published group independent components analysis (ICA) procedure outlined by Chen et al. (2013) to present the first pharmaco-EEG ICA analysis of the resting-state EEG in healthy participants administered 0.45 mg/kg dexamphetamine. Twenty-eight healthy participants between 18 and 41 were recruited. Bayesian nested-domain models that explicitly account for spatial and functional relationships were used to contrast placebo and dexamphetamine on component spectral power and several connectivity metrics. Dexamphetamine led to reductions across delta, theta, and alpha spectral power bands that were predominantly localized to Frontal and Central regions. Beta 1 and beta 2 power were reduced by dexamphetamine at Frontal ICs, while beta 2 and gamma power was enhanced by dexamphetamine in posterior regions, including the parietal, occipital-temporal, and occipital regions. Power-power coupling under dexamphetamine was similar for both states, resembling the eyes open condition under placebo. However, orthogonalized measures of power coupling and phase coupling did not show the same effect of dexamphetamine as power-power coupling. We discuss the alterations of low- and high-frequency EEG power in response to dexamphetamine within the context of disorders of dopamine regulation, in particular schizophrenia, as well as in the context of a recently hypothesized association between low-frequency power and aspects of anhedonia. Hum Brain Mapp 37:570-588, 2016. © 2015 Wiley Periodicals, Inc. PMID:26577247

  3. Electrocardiograph abnormalities revealed during laparoscopy

    PubMed Central

    Nijjer, Sukhjinder; Dubrey, Simon William

    2010-01-01

    This brief case presents a well patient in whom an electrocardiograph abnormality consistent with an accessory pathway was found during a routine procedure. We present the electrocardiographs, explain the underlying condition, and consider why the abnormality was revealed in this manner. PMID:22419949

  4. Abnormal pressure in hydrocarbon environments

    USGS Publications Warehouse

    Law, B.E.; Spencer, C.W.

    1998-01-01

    Abnormal pressures, pressures above or below hydrostatic pressures, occur on all continents in a wide range of geological conditions. According to a survey of published literature on abnormal pressures, compaction disequilibrium and hydrocarbon generation are the two most commonly cited causes of abnormally high pressure in petroleum provinces. In young (Tertiary) deltaic sequences, compaction disequilibrium is the dominant cause of abnormal pressure. In older (pre-Tertiary) lithified rocks, hydrocarbon generation, aquathermal expansion, and tectonics are most often cited as the causes of abnormal pressure. The association of abnormal pressures with hydrocarbon accumulations is statistically significant. Within abnormally pressured reservoirs, empirical evidence indicates that the bulk of economically recoverable oil and gas occurs in reservoirs with pressure gradients less than 0.75 psi/ft (17.4 kPa/m) and there is very little production potential from reservoirs that exceed 0.85 psi/ft (19.6 kPa/m). Abnormally pressured rocks are also commonly associated with unconventional gas accumulations where the pressuring phase is gas of either a thermal or microbial origin. In underpressured, thermally mature rocks, the affected reservoirs have most often experienced a significant cooling history and probably evolved from an originally overpressured system.

  5. Haem degradation in abnormal haemoglobins.

    PubMed Central

    Brown, S B; Docherty, J C

    1978-01-01

    The coupled oxidation of certain abnormal haemoglobins leads to different bile-pigment isomer distributions from that of normal haemoglobin. The isomer pattern may be correlated with the structure of the abnormal haemoglobin in the neighbourhood of the haem pocket. This is support for haem degradation by an intramolecular reaction. PMID:708385

  6. Scopolamine effects on functional brain connectivity: a pharmacological model of Alzheimer's disease.

    PubMed

    Bajo, R; Pusil, S; López, M E; Canuet, L; Pereda, E; Osipova, D; Maestú, F; Pekkonen, E

    2015-01-01

    Scopolamine administration may be considered as a psychopharmacological model of Alzheimer's disease (AD). Here, we studied a group of healthy elderly under scopolamine to test whether it elicits similar changes in brain connectivity as those observed in AD, thereby verifying a possible model of AD impairment. We did it by testing healthy elderly subjects in two experimental conditions: glycopyrrolate (placebo) and scopolamine administration. We then analyzed magnetoencephalographic (MEG) data corresponding to both conditions in resting-state with eyes closed. This analysis was performed in source space by combining a nonlinear frequency band-specific measure of functional connectivity (phase locking value, PLV) with network analysis methods. Under scopolamine, functional connectivity between several brain areas was significantly reduced as compared to placebo, in most frequency bands analyzed. Besides, regarding the two complex network indices studied (clustering and shortest path length), clustering significantly decreased in the alpha band while shortest path length significantly increased also in alpha band both after scopolamine administration. Overall our findings indicate that both PLV and graph analysis are suitable tools to measure brain connectivity changes induced by scopolamine, which causes alterations in brain connectivity apparently similar to those reported in AD. PMID:26130273

  7. Effect of current connection to the anode nozzle on plasma torch efficiency

    SciTech Connect

    Collares, M.P.; Pfender, E.

    1997-10-01

    Experiments have been performed to demonstrate the influence of the location of the electric power connection to the anode nozzle on the efficiency of dc plasma torches. The dc plasma torch used in these experiments offers the flexibility to work with different anode geometries and the possibility of connecting the electrical power to the anode at two different locations. For each set of experiments, the controllable parameters such as total gas flow rate, gas composition, and electric current were kept constant, changing only the location of the electrical connection to the anode nozzle. The efficiency of the torch, derived from a conventional energy balance, shows a significant change as the location of the electrical connection to the anode nozzle is changed. The measured mean voltage as well as the amplitude of the voltage fluctuations were also affected by the location of the electrical connection to the anode nozzle. An explanation for the arc behavior is given, based on an analysis of the forces acting on the anode arc column and their influence on the variation of the arc column length. Experimental data are in good agreement with analytical predictions.

  8. Altered effective connectivity patterns of the default mode network in Alzheimer's disease: an fMRI study.

    PubMed

    Zhong, Yufang; Huang, Liyu; Cai, Suping; Zhang, Yun; von Deneen, Karen M; Ren, Aifeng; Ren, Junchan

    2014-08-22

    The aim of this work is to investigate the differences of effective connectivity of the default mode network (DMN) in Alzheimer's disease (AD) patients and normal controls (NC). The technique of independent component analysis (ICA) was applied to identify DMN components and multivariate Granger causality analysis (mGCA) was used to explore an effective connectivity pattern. We found that: (i) connections in AD were decreased than those in NC, in terms of intensity and quantity. Posterior cingulated cortex (PCC) exhibited significant activity in NC as it connected with most of the other regions within the DMN. Besides, the PCC was the convergence center which only received interactions from other regions; (ii) right inferior temporal cortex (rITC) in the NC exhibited stronger interactions with other regions within the DMN compared with AD patients; and (iii) interactions between medial prefrontal cortex (MPFC) and bilateral inferior parietal cortex (IPC) in the NC were weaker than those in AD patients. These findings may implicate a brain dysfunction in AD patients and reveal more pathophysiological characteristics of AD. PMID:24996191

  9. Effects of Low Doses of Pioglitazone on Resting-State Functional Connectivity in Conscious Rat Brain

    PubMed Central

    Crenshaw, Donna G.; Asin, Karen; Gottschalk, William K.; Liang, Zhifeng; Zhang, Nanyin; Roses, Allen D.

    2015-01-01

    Pioglitazone (PIO) is a peroxisome proliferator-activated receptor-γ (PPARγ) agonist in clinical use for treatment of type 2 diabetes (T2DM). Accumulating evidence suggests PPARγ agonists may be useful for treating or delaying the onset of Alzheimer’s disease (AD), possibly via actions on mitochondria, and that dose strengths lower than those clinically used for T2DM may be efficacious. Our major objective was to determine if low doses of pioglitazone, administered orally, impacted brain activity. We measured blood-oxygenation-level dependent (BOLD) low-frequency fluctuations in conscious rats to map changes in brain resting-state functional connectivity due to daily, oral dosing with low-dose PIO. The connectivity in two neural circuits exhibited significant changes compared with vehicle after two days of treatment with PIO at 0.08 mg/kg/day. After 7 days of treatment with a range of PIO dose-strengths, connections between 17 pairs of brain regions were significantly affected. Functional connectivity with the CA1 region of the hippocampus, a region that is involved in memory and is affected early in the progression of AD, was specifically investigated in a seed-based analysis. This approach revealed that the spatial pattern of CA1 connectivity was consistent among all dose groups at baseline, prior to treatment with PIO, and in the control group imaged on day 7. Compared to baseline and controls, increased connectivity to CA1 was observed regionally in the hypothalamus and ventral thalamus in all PIO-treated groups, but was least pronounced in the group treated with the highest dose of PIO. These data support our hypothesis that PIO modulates neuronal and/or cerebrovascular function at dose strengths significantly lower than those used to treat T2DM and therefore may be a useful therapy for neurodegenerative diseases including AD. PMID:25671601

  10. Activation of C-F bonds in fluoroarenes by N-heterocyclic carbenes as an effective route to synthesize abnormal NHC complexes.

    PubMed

    Kim, Youngsuk; Lee, Eunsung

    2016-09-18

    IPr (1a) reacts with octafluorotoluene by an unexpected sequential substitution of fluorides in two separate rings. The resulting tetrasubstituted imidazolium salt was isolated and elaborated into Ag(i) and Au(i) complexes with a novel abnormal NHC ligand. Both IPr (1a) and IMes (1b) were also found to be moderately reactive by nucleophilic substitution of the aromatic C-F bond in a weakly-activated fluoroarene, 1-fluoro-4-trifluoromethylbenzene (5). PMID:27533338

  11. Effect of intermodular connection on fast sparse synchronization in clustered small-world neural networks

    NASA Astrophysics Data System (ADS)

    Kim, Sang-Yoon; Lim, Woochang

    2015-11-01

    We consider a clustered network with small-world subnetworks of inhibitory fast spiking interneurons and investigate the effect of intermodular connection on the emergence of fast sparsely synchronized rhythms by varying both the intermodular coupling strength Jinter and the average number of intermodular links per interneuron Msyn(inter ). In contrast to the case of nonclustered networks, two kinds of sparsely synchronized states such as modular and global synchronization are found. For the case of modular sparse synchronization, the population behavior reveals the modular structure, because the intramodular dynamics of subnetworks make some mismatching. On the other hand, in the case of global sparse synchronization, the population behavior is globally identical, independently of the cluster structure, because the intramodular dynamics of subnetworks make perfect matching. We introduce a realistic cross-correlation modularity measure, representing the matching degree between the instantaneous subpopulation spike rates of the subnetworks, and examine whether the sparse synchronization is global or modular. Depending on its magnitude, the intermodular coupling strength Jinter seems to play "dual" roles for the pacing between spikes in each subnetwork. For large Jinter, due to strong inhibition it plays a destructive role to "spoil" the pacing between spikes, while for small Jinter it plays a constructive role to "favor" the pacing between spikes. Through competition between the constructive and the destructive roles of Jinter, there exists an intermediate optimal Jinter at which the pacing degree between spikes becomes maximal. In contrast, the average number of intermodular links per interneuron Msyn(inter ) seems to play a role just to favor the pacing between spikes. With increasing Msyn(inter ), the pacing degree between spikes increases monotonically thanks to the increase in the degree of effectiveness of global communication between spikes. Furthermore, we

  12. Evaluating the Effectiveness of the 2002-2003 NASA CONNECT(TM) Program

    NASA Technical Reports Server (NTRS)

    Pinelli, Thomas E.; Lambert, Matthew A.; Williams, Amy C.

    2004-01-01

    NASA CONNECT is a research-, inquiry-, and standards-based, integrated mathematics, science, and technology series of 30-minute instructional distance learning (television and web-based) programs for students in grades 6 8. Respondents who evaluated the programs in the 2002 2003 NASA CONNECT series reported that (1) they used the programs in the series; (2) the goals and objectives for the series were met; (3) the programs were aligned with the national mathematics, science, and technology standards; (4) the program content was developmentally appropriate for grade level; and (5) the programs in the series enhanced and enriched the teaching of mathematics, science, and technology.

  13. Evaluating the Effectiveness of the 2000-2001 NASA CONNECT(TM) Program

    NASA Technical Reports Server (NTRS)

    Pinelli, Thomas E.; Frank, Kari Lou; Lambert, Matthew A.

    2002-01-01

    This report contains the results of the evaluation conducted for the 2000-2001 NASA CONNECT(TM) program conducted in March 2001. The analysis is based on the results collected from 154 surveys collected from educators registered for the program. Respondents indicated that the objectives for each program were met; the programs were aligned with the national (mathematics, science, and technology) standards; the programs were developmentally (grade level) appropriate; and the programs in the 2000-2001 NASA CONNECT(TM) series enhanced/enriched the teaching of mathematics, science, and technology.

  14. Evaluating the Effectiveness of the 2001-2002 NASA CONNECT(tm) Program

    NASA Technical Reports Server (NTRS)

    Pinelli, Thomas E.; Frank, Kari Lou; Lambert, Matthew A.; Williams, Amy C.

    2002-01-01

    NASA CONNECT(tm) is a research and standards-based, integrated mathematics, science, and technology series of 30-minute instructional distance learning (television and web-based) programs for students in grades 6-8. Respondents who evaluated the programs in the 2001-2002 NASA CONNECT(tm) series reported that (1) they used the programs in the series; (2) the goals and objectives for the series were met; (3) the programs were aligned with the national mathematics, science, and technology standards; (4) the program content was developmentally appropriate for grade level; and (5) the programs in the series enhanced and enriched the teaching of mathematics, science, and technology.

  15. Semen abnormalities with SSRI antidepressants.

    PubMed

    2015-01-01

    Despite decades of widespread use, the adverse effect profile of "selective" serotonin reuptake inhibitor (SSRI) antidepressants has still not been fully elucidated. Studies in male animals have shown delayed sexual development and reduced fertility. Three prospective cohort studies conducted in over one hundred patients exposed to an SSRI for periods ranging from 5 weeks to 24 months found altered semen param-eters after as little as 3 months of exposure: reduced sperm concentration, reduced sperm motility, a higher percentage of abnormal spermatozoa, and increased levels of sperm DNA fragmentation. One clinical trial showed growth retardation in children considered depressed who were exposed to SSRls. SSRls may have endocrine disrupting properties. Dapoxetine is a short-acting serotonin reuptake inhibitor that is chemically related to fluoxetine and marketed in the European Union for men complaining of premature ejaculation. But the corresponding European summary of product characteristics does not mention any effects on fertility. In practice, based on the data available as of mid-2014, the effects of SSRI exposure on male fertility are unclear. However, it is a risk that should be taken into account and pointed out to male patients who would like to father a child or who are experiencing fertility problems. PMID:25729824

  16. Abnormal behaviors detection using particle motion model

    NASA Astrophysics Data System (ADS)

    Chen, Yutao; Zhang, Hong; Cheng, Feiyang; Yuan, Ding; You, Yuhu

    2015-03-01

    Human abnormal behaviors detection is one of the most challenging tasks in the video surveillance for the public security control. Interaction Energy Potential model is an effective and competitive method published recently to detect abnormal behaviors, but their model of abnormal behaviors is not accurate enough, so it has some limitations. In order to solve this problem, we propose a novel Particle Motion model. Firstly, we extract the foreground to improve the accuracy of interest points detection since the complex background usually degrade the effectiveness of interest points detection largely. Secondly, we detect the interest points using the graphics features. Here, the movement of each human target can be represented by the movements of detected interest points of the target. Then, we track these interest points in videos to record their positions and velocities. In this way, the velocity angles, position angles and distance between each two points can be calculated. Finally, we proposed a Particle Motion model to calculate the eigenvalue of each frame. An adaptive threshold method is proposed to detect abnormal behaviors. Experimental results on the BEHAVE dataset and online videos show that our method could detect fight and robbery events effectively and has a promising performance.

  17. Parsing abnormal grain growth in specialty aluminas

    NASA Astrophysics Data System (ADS)

    Lawrence, Abigail Kremer

    Grain growth in alumina is strongly affected by the impurities present in the material. Certain impurity elements are known to have characteristic effects on abnormal grain growth in alumina. Specialty alumina powders contain multiple impurity species including MgO, CaO, SiO2, and Na 2O. In this work, sintered samples made from alumina powders containing various amounts of the impurities in question were characterized by their grain size and aspect ratio distributions. Multiple quantitative methods were used to characterize and classify samples with varying microstructures. The grain size distributions were used to partition the grain size population into subpopulations depending on the observed deviation from normal behavior. Using both grain size and aspect ratio a new visual representation for a microstructure was introduced called a morphology frequency map that gives a fingerprint for the material. The number of subpopulations within a sample and the shape of the distribution on the morphology map provided the basis for a classification scheme for different types of microstructures. Also using the two parameters a series of five metrics were calculated that describe the character of the abnormal grains in the sample, these were called abnormal character values. The abnormal character values describe the fraction of grains that are considered abnormal, the average magnitude of abnormality (including both grain size and aspect ratio), the average size, and variance in size. The final metric is the correlation between grain size and aspect ratio for the entire population of grains. The abnormal character values give a sense of how different from "normal" the sample is, given the assumption that a normal sample has a lognormal distribution of grain size and a Gaussian distribution of aspect ratios. In the second part of the work the quantified measures of abnormality were correlated with processing parameters such as composition and heat treatment conditions. A

  18. In vivo microscopy of microvessel oxygenation and network connections.

    PubMed

    Lee, Jennifer A; Kozikowski, Raymond T; Sorg, Brian S

    2015-03-01

    Abnormal or compromised microvascular function is a key component of various diseases. In vivo microscopy of microvessel function in preclinical models can be useful for the study of a disease state and effects of new treatments. Wide-field imaging of microvascular oxygenation via hemoglobin (Hb) saturation measurements has been applied in various applications alone and in combination with other measures of microvessel function, such as blood flow. However, most current combined imaging methods of microvessel function do not provide direct information on microvessel network connectivity or changes in connections and blood flow pathways. First-pass fluorescence (FPF) imaging of a systemically administered fluorescent contrast agent can be used to directly image blood flow pathways and connections relative to a local supplying arteriole in a quantitative manner through measurement of blood supply time (BST). Here, we demonstrate the utility of information produced by the combination of Hb saturation measurements via spectral imaging with BST measurements via FPF imaging for correlation of microvessel oxygenation with blood flow pathways and connections throughout a local network. Specifically, we show network pathway effects on oxygen transport in normal microvessels, dynamic changes associated with wound healing, and pathological effects of abnormal angiogenesis in tumor growth and development. PMID:25500481

  19. Mixed Effects Models for Resampled Network Statistics Improves Statistical Power to Find Differences in Multi-Subject Functional Connectivity.

    PubMed

    Narayan, Manjari; Allen, Genevera I

    2016-01-01

    Many complex brain disorders, such as autism spectrum disorders, exhibit a wide range of symptoms and disability. To understand how brain communication is impaired in such conditions, functional connectivity studies seek to understand individual differences in brain network structure in terms of covariates that measure symptom severity. In practice, however, functional connectivity is not observed but estimated from complex and noisy neural activity measurements. Imperfect subject network estimates can compromise subsequent efforts to detect covariate effects on network structure. We address this problem in the case of Gaussian graphical models of functional connectivity, by proposing novel two-level models that treat both subject level networks and population level covariate effects as unknown parameters. To account for imperfectly estimated subject level networks when fitting these models, we propose two related approaches-R (2) based on resampling and random effects test statistics, and R (3) that additionally employs random adaptive penalization. Simulation studies using realistic graph structures reveal that R (2) and R (3) have superior statistical power to detect covariate effects compared to existing approaches, particularly when the number of within subject observations is comparable to the size of subject networks. Using our novel models and methods to study parts of the ABIDE dataset, we find evidence of hypoconnectivity associated with symptom severity in autism spectrum disorders, in frontoparietal and limbic systems as well as in anterior and posterior cingulate cortices. PMID:27147940

  20. Mixed Effects Models for Resampled Network Statistics Improves Statistical Power to Find Differences in Multi-Subject Functional Connectivity

    PubMed Central

    Narayan, Manjari; Allen, Genevera I.

    2016-01-01

    Many complex brain disorders, such as autism spectrum disorders, exhibit a wide range of symptoms and disability. To understand how brain communication is impaired in such conditions, functional connectivity studies seek to understand individual differences in brain network structure in terms of covariates that measure symptom severity. In practice, however, functional connectivity is not observed but estimated from complex and noisy neural activity measurements. Imperfect subject network estimates can compromise subsequent efforts to detect covariate effects on network structure. We address this problem in the case of Gaussian graphical models of functional connectivity, by proposing novel two-level models that treat both subject level networks and population level covariate effects as unknown parameters. To account for imperfectly estimated subject level networks when fitting these models, we propose two related approaches—R2 based on resampling and random effects test statistics, and R3 that additionally employs random adaptive penalization. Simulation studies using realistic graph structures reveal that R2 and R3 have superior statistical power to detect covariate effects compared to existing approaches, particularly when the number of within subject observations is comparable to the size of subject networks. Using our novel models and methods to study parts of the ABIDE dataset, we find evidence of hypoconnectivity associated with symptom severity in autism spectrum disorders, in frontoparietal and limbic systems as well as in anterior and posterior cingulate cortices. PMID:27147940

  1. Effect of Long-Term Cannabis Use on Axonal Fibre Connectivity

    ERIC Educational Resources Information Center

    Zalesky, Andrew; Solowij, Nadia; Yucel, Murat; Lubman, Dan I.; Takagi, Michael; Harding, Ian H.; Lorenzetti, Valentina; Wang, Ruopeng; Searle, Karissa; Pantelis, Christos; Seal, Marc

    2012-01-01

    Cannabis use typically begins during adolescence and early adulthood, a period when cannabinoid receptors are still abundant in white matter pathways across the brain. However, few studies to date have explored the impact of regular cannabis use on white matter structure, with no previous studies examining its impact on axonal connectivity. The…

  2. The Effects of Check, Connect, and Expect on Behavioral and Academic Growth

    ERIC Educational Resources Information Center

    McDaniel, Sara C.; Houchins, David E.; Robinson, Cecil

    2016-01-01

    "Check, Connect, and Expect" (CCE) is a secondary tier behavioral intervention that provides students with levels of support including a dedicated "coach" for check-in and check-out procedures, and social skills instruction. Elementary students (n = 22) in an alternative education school setting received CCE for 13 weeks…

  3. Evaluating the Effectiveness of the 2003-2004 NASA CONNECT(trademark)Program

    NASA Technical Reports Server (NTRS)

    Caton, Randall H.; Pinelli, Thomas E.; Giersch, Christopher E.; Holmes, Ellen B.; Lambert, Matthew A.

    2005-01-01

    NASA CONNECT is an Emmy-award-winning series of instructional (distance learning) programs for grades 6-8. Produced by the NASA Center for Distance Learning, the nine programs in the 2003-2004 NASA CONNECT series are research-, inquiry-, standards-, teacher-, and technology-based and include a 30-minute program, an educator guide containing a hands-on activity, and a web-based component. The 1,500 randomly selected NASA CONNECT registered users were invited to complete an electronic (self-reported) survey that employed a 5-point Likert-type scale. Regarding NASA CONNECT, respondents reported that the programs (1) enhance the teaching of mathematics, science, and technology (4.53); (2) are aligned with the national mathematics, science, and technology standards (4.52); (3) raise student awareness of careers requiring mathematics, science, and technology (4.48); (4) demonstrate the application of mathematics, science, and technology (4.47); and (5) present women and minorities performing challenging engineering and science tasks (4.50).

  4. Enhancing Learning Effectiveness through Connectance Diagrams: A New Tool for Learning Organisations

    ERIC Educational Resources Information Center

    Lim, Sirirat Sae; Tan, Kim Hua; Platts, Ken

    2005-01-01

    Purpose: The purpose of this paper is to provide an overview of a particular approach for increasing knowledge creation in organisation. The paper provides a discussion of related concepts, processes, and a tool. Design/methodology/approach: This paper describes the reasons for drawing connectance diagrams, the process and the software. It also…

  5. The Effect of Selected Campus Connection Programs on GPA and Retention

    ERIC Educational Resources Information Center

    Chatriand, Craig M.

    2012-01-01

    Previous research has shown that participation in programs designed to connect students to campus can increase student success and retention. However, very little of this research has controlled for selections bias. The purpose of this study was to use propensity score matching to control for selection bias while analyzing three campus connection…

  6. Chromosomal abnormalities in human sperm

    SciTech Connect

    Martin, R.H.

    1985-01-01

    The ability to analyze human sperm chromosome complements after penetration of zona pellucida-free hamster eggs provides the first opportunity to study the frequency and type of chromosomal abnormalities in human gametes. Two large-scale studies have provided information on normal men. We have studied 1,426 sperm complements from 45 normal men and found an abnormality rate of 8.9%. Brandriff et al. (5) found 8.1% abnormal complements in 909 sperm from 4 men. The distribution of numerical and structural abnormalities was markedly dissimilar in the 2 studies. The frequency of aneuploidy was 5% in our sample and only 1.6% in Brandriff's, perhaps reflecting individual variability among donors. The frequency of 24,YY sperm was low: 0/1,426 and 1/909. This suggests that the estimates of nondisjunction based on fluorescent Y body data (1% to 5%) are not accurate. We have also studied men at increased risk of sperm chromosomal abnormalities. The frequency of chromosomally unbalanced sperm in 6 men heterozygous for structural abnormalities varied dramatically: 77% for t11;22, 32% for t6;14, 19% for t5;18, 13% for t14;21, and 0% for inv 3 and 7. We have also studied 13 cancer patients before and after radiotherapy and demonstrated a significant dose-dependent increase of sperm chromosome abnormalities (numerical and structural) 36 months after radiation treatment.

  7. Effect of DEM resolution and comparison between different weighting factors for hydrologic connectivity index

    NASA Astrophysics Data System (ADS)

    Cantreul, Vincent; Cavalli, Marco; Degré, Aurore

    2016-04-01

    The emerging concept of hydrological connectivity is difficult to quantify. Some indices have been proposed. The most cited is Borselli's one. It mainly uses the DEM as input. The pixel size may strongly impacts the result of the calculation. It has not been studied yet in silty areas. Another important aspect is the choice of the weighting factor which strongly influences the index value. The objective of this poster is so to compare 8 different DEM's resolutions (12, 24, 48, 72, 96, 204, 504 and 996cm) and 3 different weighting factors (factor C of Wischmeier, Manning's factor and rugosity index) in the Borselli's index calculation. The IC was calculated in a 124ha catchment (Hevillers), in the loess belt, in Belgium. The DEM used is coming from a UAV with a maximum resolution of 12 cm. Permanent covered surfaces are not considered in order to avoid artefact due to the vegetation (2% of the surface). Regarding the DEM pixel size, the IC increases for a given pixel when the pixel size decreases. That confirms some results observed in the Alpine region by Cavalli (2014). The mean difference between 12 cm and 10 m resolution is 35% with higher values up to 100% for higher connectivity zones (flow paths). Another result is the lower impact of connections in the watershed (grass strips…) at lower pixel sizes. This is linked to the small width of some connections which are sometimes comparing to cell size. Furthermore, a great loss of precision is observed from the 500 cm pixel size and upper. That remark is quite intuitive. Finally, some very well disconnected zones appear for the highest resolutions. Regarding the weighting factor, IC values calculated using C factor are lower than with the rugosity index which is only a topographic factor. With very high resolution DEM, it permits to represent the fine topography. For the C factor, the zones up to very well disconnected areas (grass strips, wood…) are well represented with lower index values than downstream

  8. Haematological abnormalities in mitochondrial disorders

    PubMed Central

    Finsterer, Josef; Frank, Marlies

    2015-01-01

    INTRODUCTION This study aimed to assess the kind of haematological abnormalities that are present in patients with mitochondrial disorders (MIDs) and the frequency of their occurrence. METHODS The blood cell counts of a cohort of patients with syndromic and non-syndromic MIDs were retrospectively reviewed. MIDs were classified as ‘definite’, ‘probable’ or ‘possible’ according to clinical presentation, instrumental findings, immunohistological findings on muscle biopsy, biochemical abnormalities of the respiratory chain and/or the results of genetic studies. Patients who had medical conditions other than MID that account for the haematological abnormalities were excluded. RESULTS A total of 46 patients (‘definite’ = 5; ‘probable’ = 9; ‘possible’ = 32) had haematological abnormalities attributable to MIDs. The most frequent haematological abnormality in patients with MIDs was anaemia. 27 patients had anaemia as their sole haematological problem. Anaemia w