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Sample records for link cortical polarity

  1. MicroRNA-338 modulates cortical neuronal placement and polarity.

    Science.gov (United States)

    Kos, Aron; de Mooij-Malsen, Annetrude J; van Bokhoven, Hans; Kaplan, Barry B; Martens, Gerard J; Kolk, Sharon M; Aschrafi, Armaz

    2017-07-03

    The precise spatial and temporal regulation of gene expression orchestrates the many intricate processes during brain development. In the present study we examined the role of the brain-enriched microRNA-338 (miR-338) during mouse cortical development. Reduction of miR-338 levels in the developing mouse cortex, using a sequence-specific miR-sponge, resulted in a loss of neuronal polarity in the cortical plate and significantly reduced the number of neurons within this cortical layer. Conversely, miR-338 overexpression in developing mouse cortex increased the number of neurons, which exhibited a multipolar morphology. All together, our results raise the possibility for a direct role for this non-coding RNA, which was recently associated with schizophrenia, in the regulation of cortical neuronal polarity and layer placement.

  2. ImaEdge - a platform for quantitative analysis of the spatiotemporal dynamics of cortical proteins during cell polarization.

    Science.gov (United States)

    Zhang, Zhen; Lim, Yen Wei; Zhao, Peng; Kanchanawong, Pakorn; Motegi, Fumio

    2017-12-15

    Cell polarity involves the compartmentalization of the cell cortex. The establishment of cortical compartments arises from the spatial bias in the activity and concentration of cortical proteins. The mechanistic dissection of cell polarity requires the accurate detection of dynamic changes in cortical proteins, but the fluctuations of cell shape and the inhomogeneous distributions of cortical proteins greatly complicate the quantitative extraction of their global and local changes during cell polarization. To address these problems, we introduce an open-source software package, ImaEdge, which automates the segmentation of the cortex from time-lapse movies, and enables quantitative extraction of cortical protein intensities. We demonstrate that ImaEdge enables efficient and rigorous analysis of the dynamic evolution of cortical PAR proteins during Caenorhabditis elegans embryogenesis. It is also capable of accurate tracking of varying levels of transgene expression and discontinuous signals of the actomyosin cytoskeleton during multiple rounds of cell division. ImaEdge provides a unique resource for quantitative studies of cortical polarization, with the potential for application to many types of polarized cells.This article has an associated First Person interview with the first authors of the paper. © 2017. Published by The Company of Biologists Ltd.

  3. A Mechanistic Link from GABA to Cortical Architecture and Perception.

    Science.gov (United States)

    Kolasinski, James; Logan, John P; Hinson, Emily L; Manners, Daniel; Divanbeighi Zand, Amir P; Makin, Tamar R; Emir, Uzay E; Stagg, Charlotte J

    2017-06-05

    Understanding both the organization of the human cortex and its relation to the performance of distinct functions is fundamental in neuroscience. The primary sensory cortices display topographic organization, whereby receptive fields follow a characteristic pattern, from tonotopy to retinotopy to somatotopy [1]. GABAergic signaling is vital to the maintenance of cortical receptive fields [2]; however, it is unclear how this fine-grain inhibition relates to measurable patterns of perception [3, 4]. Based on perceptual changes following perturbation of the GABAergic system, it is conceivable that the resting level of cortical GABAergic tone directly relates to the spatial specificity of activation in response to a given input [5-7]. The specificity of cortical activation can be considered in terms of cortical tuning: greater cortical tuning yields more localized recruitment of cortical territory in response to a given input. We applied a combination of fMRI, MR spectroscopy, and psychophysics to substantiate the link between the cortical neurochemical milieu, the tuning of cortical activity, and variability in perceptual acuity, using human somatosensory cortex as a model. We provide data that explain human perceptual acuity in terms of both the underlying cellular and metabolic processes. Specifically, higher concentrations of sensorimotor GABA are associated with more selective cortical tuning, which in turn is associated with enhanced perception. These results show anatomical and neurochemical specificity and are replicated in an independent cohort. The mechanistic link from neurochemistry to perception provides a vital step in understanding population variability in sensory behavior, informing metabolic therapeutic interventions to restore perceptual abilities clinically. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  4. Vestibulo-cortical Hemispheric Dominance: the link between Anxiety and the Vestibular System?

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    Bednarczuk, Nadja F; Casanovas Ortega, Marta; Fluri, Anne-Sophie; Arshad, Qadeer

    2018-05-16

    Vestibular processing and anxiety networks are functionally intertwined, as demonstrated by reports of reciprocal influences upon each other. Yet whether there is an underlying link between these two systems remains unknown Previous findings have highlighted the involvement of hemispheric lateralisation in processing of both anxiety and vestibular signals. Accordingly, we explored the interaction between vestibular cortical processing and anxiety by assessing the relationship between anxiety levels and the degree of hemispheric lateralisation of vestibulo-cortical processing in 64 right-handed, healthy individuals. Vestibulo-cortical hemispheric lateralisation was determined by gaging the degree of caloric-induced nystagmus suppression following modulation of cortical excitability using trans-cranial direct current stimulation targeted over the posterior parietal cortex, an area implicated in the processing of vestibular signals. The degree of nystagmus suppression yields an objective biomarker, allowing the quantification of the degree of right vestibulo-cortical hemisphere dominance. Anxiety levels were quantified using the Trait component of the Spielberger State-Trait Anxiety Questionnaire. Our findings demonstrate that the degree of an individual's vestibulo-cortical hemispheric dominance correlates with their anxiety levels. That is, those individuals with greater right hemispheric vestibulo-cortical dominance exhibited lower levels of anxiety. By extension, our results support the notion that hemispheric lateralisation determines an individual's emotional processing, thereby linking cortical circuits involved in processing anxiety and vestibular signals respectively. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  5. Quad-Polarization Transmission for High-Capacity IM/DD Links

    DEFF Research Database (Denmark)

    Estaran Tolosa, Jose Manuel; Castaneda, Mario A. Usuga; Porto da Silva, Edson

    2014-01-01

    We report the first experimental demonstration of IM/DD links usi ng four states of polarization. Fiber - Induced polarization rotation is compensated with a simple tracking algorithm operating on the Stokes space. The principle is prove n at 128 Gb/s over 2 - km SSMF......We report the first experimental demonstration of IM/DD links usi ng four states of polarization. Fiber - Induced polarization rotation is compensated with a simple tracking algorithm operating on the Stokes space. The principle is prove n at 128 Gb/s over 2 - km SSMF...

  6. Dynein Transmits Polarized Actomyosin Cortical Flows to Promote Centrosome Separation

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    Alessandro De Simone

    2016-03-01

    Full Text Available The two centrosomes present at the onset of mitosis must separate in a timely and accurate fashion to ensure proper bipolar spindle assembly. The minus-end-directed motor dynein plays a pivotal role in centrosome separation, but the underlying mechanisms remain elusive, particularly regarding how dynein coordinates this process in space and time. We addressed these questions in the one-cell C. elegans embryo, using a combination of 3D time-lapse microscopy and computational modeling. Our analysis reveals that centrosome separation is powered by the joint action of dynein at the nuclear envelope and at the cell cortex. Strikingly, we demonstrate that dynein at the cell cortex acts as a force-transmitting device that harnesses polarized actomyosin cortical flows initiated by the centrosomes earlier in the cell cycle. This mechanism elegantly couples cell polarization with centrosome separation, thus ensuring faithful cell division.

  7. Bi-polarized translation of ascidian maternal mRNA determinant pem-1 associated with regulators of the translation machinery on cortical Endoplasmic Reticulum (cER).

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    Paix, Alexandre; Le Nguyen, Phuong Ngan; Sardet, Christian

    2011-09-01

    Polarized cortical mRNA determinants such as maternal macho-1 and pem-1 in ascidians, like budding yeast mating factor ASH1 reside on the cER-mRNA domain a subdomain of cortical Endoplasmic Reticulum(ER) and are translated in its vicinity. Using high resolution imaging and isolated cortical fragments prepared from eggs and embryos we now find that macho-1 and pem-1 RNAs co-localize with phospho-protein regulators of translation initiation (MnK/4EBP/S6K). Translation of cortical pem-1 RNA follows its bi-polarized relocalization. About 10 min after fertilization or artificial activation with a calcium ionophore, PEM1 protein is detected in the vegetal cortex in the vicinity of pem-1 RNA. About 40 min after fertilization-when pem-1 RNA and P-MnK move to the posterior pole-PEM1 protein remains in place forming a network of cortical patches anchored at the level of the zygote plasma membrane before disappearing. Cortical PEM1 protein is detected again at the 4 cell stage in the posterior centrosome attracting body (CAB) region where the cER-mRNA domain harboring pem-1/P-MnK/P-4EBP/P-S6K is concentrated. Bi-polarized PEM1 protein signals are not detected when pem-1 morpholinos are injected into eggs or zygotes or when MnK is inhibited. We propose that localized translation of the pem-1 RNA determinant is triggered by the fertilization/calcium wave and that the process is controlled by phospho-protein regulators of translation initiation co-localized with the RNA determinant on a sub-domain of the cortical Endoplasmic Reticulum. Copyright © 2011 Elsevier Inc. All rights reserved.

  8. Quaternary Polarization-Multiplexed Subsystem for High-Capacity IM/DD Optical Data Links

    DEFF Research Database (Denmark)

    Estaran Tolosa, Jose Manuel; Usuga Castaneda, Mario A.; Porto da Silva, Edson

    2015-01-01

    We demonstrate for the first time an intensitymodulated direct-detection link using four states of polarization. The four data-independent tributaries are each assigned distinct states of polarization to enable the receiver to separate the signals. Polarization rotation due to propagation over op...

  9. Mapping cortical mesoscopic networks of single spiking cortical or sub-cortical neurons.

    Science.gov (United States)

    Xiao, Dongsheng; Vanni, Matthieu P; Mitelut, Catalin C; Chan, Allen W; LeDue, Jeffrey M; Xie, Yicheng; Chen, Andrew Cn; Swindale, Nicholas V; Murphy, Timothy H

    2017-02-04

    Understanding the basis of brain function requires knowledge of cortical operations over wide-spatial scales, but also within the context of single neurons. In vivo, wide-field GCaMP imaging and sub-cortical/cortical cellular electrophysiology were used in mice to investigate relationships between spontaneous single neuron spiking and mesoscopic cortical activity. We make use of a rich set of cortical activity motifs that are present in spontaneous activity in anesthetized and awake animals. A mesoscale spike-triggered averaging procedure allowed the identification of motifs that are preferentially linked to individual spiking neurons by employing genetically targeted indicators of neuronal activity. Thalamic neurons predicted and reported specific cycles of wide-scale cortical inhibition/excitation. In contrast, spike-triggered maps derived from single cortical neurons yielded spatio-temporal maps expected for regional cortical consensus function. This approach can define network relationships between any point source of neuronal spiking and mesoscale cortical maps.

  10. Integrin-linked kinase interactions with ELMO2 modulate cell polarity.

    Science.gov (United States)

    Ho, Ernest; Irvine, Tames; Vilk, Gregory J A; Lajoie, Gilles; Ravichandran, Kodi S; D'Souza, Sudhir J A; Dagnino, Lina

    2009-07-01

    Cell polarization is a key prerequisite for directed migration during development, tissue regeneration, and metastasis. Integrin-linked kinase (ILK) is a scaffold protein essential for cell polarization, but very little is known about the precise mechanisms whereby ILK modulates polarization in normal epithelia. Elucidating these mechanisms is essential to understand tissue morphogenesis, transformation, and repair. Here we identify a novel ILK protein complex that includes Engulfment and Cell Motility 2 (ELMO2). We also demonstrate the presence of RhoG in ILK-ELMO2 complexes, and the localization of this multiprotein species specifically to the leading lamellipodia of polarized cells. Significantly, the ability of RhoG to bind ELMO is crucial for ILK induction of cell polarization, and the joint expression of ILK and ELMO2 synergistically promotes the induction of front-rear polarity and haptotactic migration. This places RhoG-ELMO2-ILK complexes in a key position for the development of cell polarity and forward movement. Although ILK is a component of many diverse multiprotein species that may contribute to cell polarization, expression of dominant-negative ELMO2 mutants is sufficient to abolish the ability of ILK to promote cell polarization. Thus, its interaction with ELMO2 and RhoG is essential for the ability of ILK to induce front-rear cell polarity.

  11. Crosstalk cancellation on linearly and circularly polarized communications satellite links

    Science.gov (United States)

    Overstreet, W. P.; Bostian, C. W.

    1979-01-01

    The paper discusses the cancellation network approach for reducing crosstalk caused by depolarization on a dual-polarized communications satellite link. If the characteristics of rain depolarization are sufficiently well known, the cancellation network can be designed in a way that reduces system complexity, the most important parameter being the phase of the cross-polarized signal. Relevant theoretical calculations and experimental data are presented. The simplicity of the cancellation system proposed makes it ideal for use with small domestic or private earth terminals.

  12. Allostatic Load Is Linked to Cortical Thickness Changes Depending on Body-Weight Status

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    Jonatan Ottino-González

    2017-12-01

    Full Text Available Objective: Overweight (body mass index or BMI ≥ 25 kg/m2 and stress interact with each other in complex ways. Overweight promotes chronic low-inflammation states, while stress is known to mediate caloric intake. Both conditions are linked to several avoidable health problems and to cognitive decline, brain atrophy, and dementia. Since it was proposed as a framework for the onset of mental illness, the allostatic load model has received increasing attention. Although changes in health and cognition related to overweight and stress are well-documented separately, the association between allostatic load and brain integrity has not been addressed in depth, especially among overweight subjects.Method: Thirty-four healthy overweight-to-obese and 29 lean adults underwent blood testing, neuropsychological examination, and magnetic resonance imaging to assess the relationship between cortical thickness and allostatic load, represented as an index of 15 biomarkers (this is, systolic and diastolic arterial tension, glycated hemoglobin, glucose, creatinine, total cholesterol, HDL and LDL cholesterol, triglycerides, c-reactive protein, interleukin-6, insulin, cortisol, fibrinogen, and leptin.Results: Allostatic load indexes showed widespread positive and negative significant correlations (p < 0.01 with cortical thickness values depending on body-weight status.Conclusion: The increase of allostatic load is linked to changes in the gray matter composition of regions monitoring behavior, sensory-reward processing, and general cognitive function.

  13. Allostatic Load Is Linked to Cortical Thickness Changes Depending on Body-Weight Status

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    Ottino-González, Jonatan; Jurado, María A.; García-García, Isabel; Segura, Bàrbara; Marqués-Iturria, Idoia; Sender-Palacios, María J.; Tor, Encarnació; Prats-Soteras, Xavier; Caldú, Xavier; Junqué, Carme; Garolera, Maite

    2017-01-01

    Objective: Overweight (body mass index or BMI ≥ 25 kg/m2) and stress interact with each other in complex ways. Overweight promotes chronic low-inflammation states, while stress is known to mediate caloric intake. Both conditions are linked to several avoidable health problems and to cognitive decline, brain atrophy, and dementia. Since it was proposed as a framework for the onset of mental illness, the allostatic load model has received increasing attention. Although changes in health and cognition related to overweight and stress are well-documented separately, the association between allostatic load and brain integrity has not been addressed in depth, especially among overweight subjects. Method: Thirty-four healthy overweight-to-obese and 29 lean adults underwent blood testing, neuropsychological examination, and magnetic resonance imaging to assess the relationship between cortical thickness and allostatic load, represented as an index of 15 biomarkers (this is, systolic and diastolic arterial tension, glycated hemoglobin, glucose, creatinine, total cholesterol, HDL and LDL cholesterol, triglycerides, c-reactive protein, interleukin-6, insulin, cortisol, fibrinogen, and leptin). Results: Allostatic load indexes showed widespread positive and negative significant correlations (p < 0.01) with cortical thickness values depending on body-weight status. Conclusion: The increase of allostatic load is linked to changes in the gray matter composition of regions monitoring behavior, sensory-reward processing, and general cognitive function. PMID:29375342

  14. Cortical Thinning and Altered Cortico-Cortical Structural Covariance of the Default Mode Network in Patients with Persistent Insomnia Symptoms.

    Science.gov (United States)

    Suh, Sooyeon; Kim, Hosung; Dang-Vu, Thien Thanh; Joo, Eunyeon; Shin, Chol

    2016-01-01

    Recent studies have suggested that structural abnormalities in insomnia may be linked with alterations in the default-mode network (DMN). This study compared cortical thickness and structural connectivity linked to the DMN in patients with persistent insomnia (PI) and good sleepers (GS). The current study used a clinical subsample from the longitudinal community-based Korean Genome and Epidemiology Study (KoGES). Cortical thickness and structural connectivity linked to the DMN in patients with persistent insomnia symptoms (PIS; n = 57) were compared to good sleepers (GS; n = 40). All participants underwent MRI acquisition. Based on literature review, we selected cortical regions corresponding to the DMN. A seed-based structural covariance analysis measured cortical thickness correlation between each seed region of the DMN and other cortical areas. Association of cortical thickness and covariance with sleep quality and neuropsychological assessments were further assessed. Compared to GS, cortical thinning was found in PIS in the anterior cingulate cortex, precentral cortex, and lateral prefrontal cortex. Decreased structural connectivity between anterior and posterior regions of the DMN was observed in the PIS group. Decreased structural covariance within the DMN was associated with higher PSQI scores. Cortical thinning in the lateral frontal lobe was related to poor performance in executive function in PIS. Disrupted structural covariance network in PIS might reflect malfunctioning of antero-posterior disconnection of the DMN during the wake to sleep transition that is commonly found during normal sleep. The observed structural network alteration may further implicate commonly observed sustained sleep difficulties and cognitive impairment in insomnia. © 2016 Associated Professional Sleep Societies, LLC.

  15. CELSR2, encoding a planar cell polarity protein, is a putative gene in Joubert syndrome with cortical heterotopia, microophthalmia, and growth hormone deficiency.

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    Vilboux, Thierry; Malicdan, May Christine V; Roney, Joseph C; Cullinane, Andrew R; Stephen, Joshi; Yildirimli, Deniz; Bryant, Joy; Fischer, Roxanne; Vemulapalli, Meghana; Mullikin, James C; Steinbach, Peter J; Gahl, William A; Gunay-Aygun, Meral

    2017-03-01

    Joubert syndrome is a ciliopathy characterized by a specific constellation of central nervous system malformations that result in the pathognomonic "molar tooth sign" on imaging. More than 27 genes are associated with Joubert syndrome, but some patients do not have mutations in any of these genes. Celsr1, Celsr2, and Celsr3 are the mammalian orthologues of the drosophila planar cell polarity protein, flamingo; they play important roles in neural development, including axon guidance, neuronal migration, and cilium polarity. Here, we report bi-allelic mutations in CELSR2 in a Joubert patient with cortical heterotopia, microophthalmia, and growth hormone deficiency. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  16. Plasticity during Sleep Is Linked to Specific Regulation of Cortical Circuit Activity

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    Niels Niethard

    2017-09-01

    Full Text Available Sleep is thought to be involved in the regulation of synaptic plasticity in two ways: by enhancing local plastic processes underlying the consolidation of specific memories and by supporting global synaptic homeostasis. Here, we briefly summarize recent structural and functional studies examining sleep-associated changes in synaptic morphology and neural excitability. These studies point to a global down-scaling of synaptic strength across sleep while a subset of synapses increases in strength. Similarly, neuronal excitability on average decreases across sleep, whereas subsets of neurons increase firing rates across sleep. Whether synapse formation and excitability is down or upregulated across sleep appears to partly depend on the cell’s activity level during wakefulness. Processes of memory-specific upregulation of synapse formation and excitability are observed during slow wave sleep (SWS, whereas global downregulation resulting in elimination of synapses and decreased neural firing is linked to rapid eye movement sleep (REM sleep. Studies of the excitation/inhibition balance in cortical circuits suggest that both processes are connected to a specific inhibitory regulation of cortical principal neurons, characterized by an enhanced perisomatic inhibition via parvalbumin positive (PV+ cells, together with a release from dendritic inhibition by somatostatin positive (SOM+ cells. Such shift towards increased perisomatic inhibition of principal cells appears to be a general motif which underlies the plastic synaptic changes observed during sleep, regardless of whether towards up or downregulation.

  17. 100 Gbps IM/DD links using quad-polarization: Performance, complexity, and power dissipation

    DEFF Research Database (Denmark)

    Saldaña Cercos, Silvia; Piels, Molly; Estaran Tolosa, Jose Manuel

    2015-01-01

    A computational complexity, power consumption, and receiver sensitivity analysis for three different scenarios for short-range direct detection links is presented: 1) quad-polarization, 2) wavelength division multiplexing (WDM), and 3) parallel optics. Results show that the power consumption pena...... sensitivity of 4.4 dBm...

  18. Congenital olfactory impairment is linked to cortical changes in prefrontal and limbic brain regions

    DEFF Research Database (Denmark)

    Karstensen, Helena Gásdal; Vestergaard, Martin; Baaré, William F C

    2018-01-01

    differently in individuals who suffer from lifelong olfactory deprivation relative to healthy normosmic individuals. To address this question, we examined if regional variations in gray matter volume were associated with smell ability in seventeen individuals with isolated congenital olfactory impairment (COI...... in left middle frontal gyrus and right superior frontal sulcus (SFS). COI subjects with severe olfactory impairment (anosmia) had reduced grey matter volume in the left mOFC and increased volume in right piriform cortex and SFS. Within the COI group olfactory ability, measured with the "Sniffin' Sticks...... piriform cortex, while olfactory identification was negatively associated with right SFS volume. Our findings suggest that lifelong olfactory deprivation trigger changes in the cortical volume of prefrontal and limbic brain regions previously linked to olfactory memory....

  19. Spatial integration and cortical dynamics.

    OpenAIRE

    Gilbert, C D; Das, A; Ito, M; Kapadia, M; Westheimer, G

    1996-01-01

    Cells in adult primary visual cortex are capable of integrating information over much larger portions of the visual field than was originally thought. Moreover, their receptive field properties can be altered by the context within which local features are presented and by changes in visual experience. The substrate for both spatial integration and cortical plasticity is likely to be found in a plexus of long-range horizontal connections, formed by cortical pyramidal cells, which link cells wi...

  20. Computational modeling of epidural cortical stimulation

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    Wongsarnpigoon, Amorn; Grill, Warren M.

    2008-12-01

    Epidural cortical stimulation (ECS) is a developing therapy to treat neurological disorders. However, it is not clear how the cortical anatomy or the polarity and position of the electrode affects current flow and neural activation in the cortex. We developed a 3D computational model simulating ECS over the precentral gyrus. With the electrode placed directly above the gyrus, about half of the stimulus current flowed through the crown of the gyrus while current density was low along the banks deep in the sulci. Beneath the electrode, neurons oriented perpendicular to the cortical surface were depolarized by anodic stimulation, and neurons oriented parallel to the boundary were depolarized by cathodic stimulation. Activation was localized to the crown of the gyrus, and neurons on the banks deep in the sulci were not polarized. During regulated voltage stimulation, the magnitude of the activating function was inversely proportional to the thickness of the CSF and dura. During regulated current stimulation, the activating function was not sensitive to the thickness of the dura but was slightly more sensitive than during regulated voltage stimulation to the thickness of the CSF. Varying the width of the gyrus and the position of the electrode altered the distribution of the activating function due to changes in the orientation of the neurons beneath the electrode. Bipolar stimulation, although often used in clinical practice, reduced spatial selectivity as well as selectivity for neuron orientation.

  1. Molecular networks linked by Moesin drive remodeling of the cell cortex during mitosis

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    Roubinet, Chantal; Decelle, Barbara; Chicanne, Gaëtan; Dorn, Jonas F.; Payrastre, Bernard; Payre, François; Carreno, Sébastien

    2011-01-01

    The cortical mechanisms that drive the series of mitotic cell shape transformations remain elusive. In this paper, we identify two novel networks that collectively control the dynamic reorganization of the mitotic cortex. We demonstrate that Moesin, an actin/membrane linker, integrates these two networks to synergize the cortical forces that drive mitotic cell shape transformations. We find that the Pp1-87B phosphatase restricts high Moesin activity to early mitosis and down-regulates Moesin at the polar cortex, after anaphase onset. Overactivation of Moesin at the polar cortex impairs cell elongation and thus cytokinesis, whereas a transient recruitment of Moesin is required to retract polar blebs that allow cortical relaxation and dissipation of intracellular pressure. This fine balance of Moesin activity is further adjusted by Skittles and Pten, two enzymes that locally produce phosphoinositol 4,5-bisphosphate and thereby, regulate Moesin cortical association. These complementary pathways provide a spatiotemporal framework to explain how the cell cortex is remodeled throughout cell division. PMID:21969469

  2. Spatial integration and cortical dynamics.

    Science.gov (United States)

    Gilbert, C D; Das, A; Ito, M; Kapadia, M; Westheimer, G

    1996-01-23

    Cells in adult primary visual cortex are capable of integrating information over much larger portions of the visual field than was originally thought. Moreover, their receptive field properties can be altered by the context within which local features are presented and by changes in visual experience. The substrate for both spatial integration and cortical plasticity is likely to be found in a plexus of long-range horizontal connections, formed by cortical pyramidal cells, which link cells within each cortical area over distances of 6-8 mm. The relationship between horizontal connections and cortical functional architecture suggests a role in visual segmentation and spatial integration. The distribution of lateral interactions within striate cortex was visualized with optical recording, and their functional consequences were explored by using comparable stimuli in human psychophysical experiments and in recordings from alert monkeys. They may represent the substrate for perceptual phenomena such as illusory contours, surface fill-in, and contour saliency. The dynamic nature of receptive field properties and cortical architecture has been seen over time scales ranging from seconds to months. One can induce a remapping of the topography of visual cortex by making focal binocular retinal lesions. Shorter-term plasticity of cortical receptive fields was observed following brief periods of visual stimulation. The mechanisms involved entailed, for the short-term changes, altering the effectiveness of existing cortical connections, and for the long-term changes, sprouting of axon collaterals and synaptogenesis. The mutability of cortical function implies a continual process of calibration and normalization of the perception of visual attributes that is dependent on sensory experience throughout adulthood and might further represent the mechanism of perceptual learning.

  3. Exposure to high glutamate concentration activates aerobic glycolysis but inhibits ATP-linked respiration in cultured cortical astrocytes.

    Science.gov (United States)

    Shen, Yao; Tian, Yueyang; Shi, Xiaojie; Yang, Jianbo; Ouyang, Li; Gao, Jieqiong; Lu, Jianxin

    2014-08-01

    Astrocytes play a key role in removing the synaptically released glutamate from the extracellular space and maintaining the glutamate below neurotoxic level in the brain. However, high concentration of glutamate leads to toxicity in astrocytes, and the underlying mechanisms are unclear. The purpose of this study was to investigate whether energy metabolism disorder, especially impairment of mitochondrial respiration, is involved in the glutamate-induced gliotoxicity. Exposure to 10-mM glutamate for 48 h stimulated glycolysis and respiration in astrocytes. However, the increased oxygen consumption was used for proton leak and non-mitochondrial respiration, but not for oxidative phosphorylation and ATP generation. When the exposure time extended to 72 h, glycolysis was still activated for ATP generation, but the mitochondrial ATP-linked respiration of astrocytes was reduced. The glutamate-induced astrocyte damage can be mimicked by the non-metabolized substrate d-aspartate but reversed by the non-selective glutamate transporter inhibitor TBOA. In addition, the glutamate toxicity can be partially reversed by vitamin E. These findings demonstrate that changes of bioenergetic profile occur in cultured cortical astrocytes exposed to high concentration of glutamate and highlight the role of mitochondria respiration in glutamate-induced gliotoxicity in cortical astrocytes. Copyright © 2014 John Wiley & Sons, Ltd.

  4. Performance Analysis of Polarization Modulated DirectDetection Optical CDMA Systems over Turbulent FSO LinksModeled by the Gamma-Gamma Distribution

    Directory of Open Access Journals (Sweden)

    Fan Bai

    2015-01-01

    Full Text Available This paper proposes a theoretical study to characterize the transmission of optical code division multiple access (CDMA systems deploying polarization shift keying (PolSK over a free space optical (FSO link under the impact of atmospheric turbulence. In our analysis, a novel transceiver architecture for atmospheric OCDMA FSO systems based on polarization modulation with direct detection is proposed and discussed. A detailed analytical model for PolSK-OCDMA systems over a turbulent FSO link is provided. Further, we derive a closed-form bit error ratio (BER and outage probability expressions, taking into account the multiple-access interference (MAI, optical noise and the atmospheric turbulence effect on the FSO link modeled by the Gamma-Gamma distribution. Finally, the results of this study show the most significant parameters that degrade the transmission performance of the PolSK-OCDMA signal over FSO links and indicate that the proposed approach offers improved bit error ratio (BER performances compared to the on-off-keying (OOK modulation scheme in the presence of turbulence.

  5. Functional specialisation within the cortical language network: effects of cortical dysfunction.

    Science.gov (United States)

    Vandenberghe, R

    2007-01-01

    In the 1990's neuroanatomical models of language and semantic memory have been mainly based on functional neuroimaging studies of brain activity in healthy volunteers and correlational studies between structural lesions in patients and behavioral deficits. In this paper we present a novel approach where we test models that have been developed in healthy volunteers by means of functional imaging in patients in combination with behavioral studies. Study populations consist of patients with focal cortical stroke (n = 2), amnestic mild cognitive impairment (n = 14) and primary progressive aphasia (n = 18). The experiments provide converging evidence that 1. the integrity of the right mid- and anterior fusiform gyrus is required for full and detailed retrieval of knowledge of visual attributes of concrete entities 2. the left posterior superior temporal sulcus is critically involved in lexical-semantic retrieval 3. the anterior temporal pole to the left functions as an associative structure that links the representations of meaning that are distribured over the cortical brain surface. Our experiments also provide us with new insight into the degradation and re-organisation of the language system in cortical neurodegenerative disease.

  6. The Unique Brain Anatomy of Meditation Practitioners: Alterations in Cortical Gyrification

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    Eileen eLuders

    2012-02-01

    Full Text Available Several cortical regions are reported to vary in meditation practitioners. However, since prior analyses were focused on examining gray matter or cortical thickness, additional effects with respect to other cortical features might have remained undetected. Gyrification (the pattern and degree of cortical folding is an important cerebral characteristic related to the geometry of the brain’s surface. Cortical folding occurs early in development and might be linked to behavioral traits. Thus, exploring cortical gyrification in long-term meditators may provide additional clues with respect to the underlying anatomical correlates of meditation. This study examined cortical gyrification in a large sample (n=100 of meditators and controls, carefully matched for sex and age. Cortical gyrification was established via calculating mean curvature across thousands of vertices on individual cortical surface models. Pronounced group differences indicating larger gyrification in meditators were evident within the left precentral gyrus, right fusiform gyrus, right cuneus, as well as left and right anterior dorsal insula (the latter representing the global significance maximum. Although the exact functional implications of larger cortical gyrification remain to be established, these findings suggest the insula to be a key structure involved in aspects of meditation. For example, variations in insular complexity could affect the regulation of well-known distractions in the process of meditation, such as daydreaming, mind-wandering, and projections into past or future. Moreover, given that meditators are masters in introspection, awareness, and emotional control, increased insular gyrification may reflect an ideal integration of autonomic, affective, and cognitive processes. Due to the cross-sectional nature of this study, further research is necessary determine the relative contribution of nature and nurture to links between cortical gyrification and meditation.

  7. Epidermal growth factor induction of front–rear polarity and migration in keratinocytes is mediated by integrin-linked kinase and ELMO2

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    Ho, Ernest; Dagnino, Lina

    2012-01-01

    Epidermal growth factor (EGF) is a potent chemotactic and mitogenic factor for epidermal keratinocytes, and these properties are central for normal epidermal regeneration after injury. The involvement of mitogen-activated protein kinases as mediators of the proliferative effects of EGF is well established. However, the molecular mechanisms that mediate motogenic responses to this growth factor are not clearly understood. An obligatory step for forward cell migration is the development of front–rear polarity and formation of lamellipodia at the leading edge. We show that stimulation of epidermal keratinocytes with EGF, but not with other growth factors, induces development of front–rear polarity and directional migration through a pathway that requires integrin-linked kinase (ILK), Engulfment and Cell Motility-2 (ELMO2), integrin β1, and Rac1. Furthermore, EGF induction of front–rear polarity and chemotaxis require the tyrosine kinase activity of the EGF receptor and are mediated by complexes containing active RhoG, ELMO2, and ILK. Our findings reveal a novel link between EGF receptor stimulation, ILK-containing complexes, and activation of small Rho GTPases necessary for acquisition of front–rear polarity and forward movement. PMID:22160594

  8. Epidermal growth factor induction of front-rear polarity and migration in keratinocytes is mediated by integrin-linked kinase and ELMO2.

    Science.gov (United States)

    Ho, Ernest; Dagnino, Lina

    2012-02-01

    Epidermal growth factor (EGF) is a potent chemotactic and mitogenic factor for epidermal keratinocytes, and these properties are central for normal epidermal regeneration after injury. The involvement of mitogen-activated protein kinases as mediators of the proliferative effects of EGF is well established. However, the molecular mechanisms that mediate motogenic responses to this growth factor are not clearly understood. An obligatory step for forward cell migration is the development of front-rear polarity and formation of lamellipodia at the leading edge. We show that stimulation of epidermal keratinocytes with EGF, but not with other growth factors, induces development of front-rear polarity and directional migration through a pathway that requires integrin-linked kinase (ILK), Engulfment and Cell Motility-2 (ELMO2), integrin β1, and Rac1. Furthermore, EGF induction of front-rear polarity and chemotaxis require the tyrosine kinase activity of the EGF receptor and are mediated by complexes containing active RhoG, ELMO2, and ILK. Our findings reveal a novel link between EGF receptor stimulation, ILK-containing complexes, and activation of small Rho GTPases necessary for acquisition of front-rear polarity and forward movement.

  9. Jealousy increased by induced relative left frontal cortical activity.

    Science.gov (United States)

    Kelley, Nicholas J; Eastwick, Paul W; Harmon-Jones, Eddie; Schmeichel, Brandon J

    2015-10-01

    Asymmetric frontal cortical activity may be one key to the process linking social exclusion to jealous feelings. The current research examined the causal role of asymmetric frontal brain activity in modulating jealousy in response to social exclusion. Transcranial direct-current stimulation (tDCS) over the frontal cortex to manipulate asymmetric frontal cortical activity was combined with a modified version of the Cyberball paradigm designed to induce jealousy. After receiving 15 min of tDCS, participants were excluded by a desired partner and reported how jealous they felt. Among individuals who were excluded, tDCS to increase relative left frontal cortical activity caused greater levels of self-reported jealousy compared to tDCS to increase relative right frontal cortical activity or sham stimulation. Limitations concerning the specificity of this effect and implications for the role of the asymmetric prefrontal cortical activity in motivated behaviors are discussed. (c) 2015 APA, all rights reserved).

  10. Optical-wireless-optical full link for polarization multiplexing quadrature amplitude/phase modulation signal transmission.

    Science.gov (United States)

    Li, Xinying; Yu, Jianjun; Chi, Nan; Zhang, Junwen

    2013-11-15

    We propose and experimentally demonstrate an optical wireless integration system at the Q-band, in which up to 40 Gb/s polarization multiplexing multilevel quadrature amplitude/phase modulation (PM-QAM) signal can be first transmitted over 20 km single-mode fiber-28 (SMF-28), then delivered over a 2 m 2 × 2 multiple-input multiple-output wireless link, and finally transmitted over another 20 km SMF-28. The PM-QAM modulated wireless millimeter-wave (mm-wave) signal at 40 GHz is generated based on the remote heterodyning technique, and demodulated by the radio-frequency transparent photonic technique based on homodyne coherent detection and baseband digital signal processing. The classic constant modulus algorithm equalization is used at the receiver to realize polarization demultiplexing of the PM-QAM signal. For the first time, to the best of our knowledge, we realize the conversion of the PM-QAM modulated wireless mm-wave signal to the optical signal as well as 20 km fiber transmission of the converted optical signal.

  11. Linking cortical microtubule attachment and exocytosis [version 1; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Ivar Noordstra

    2017-04-01

    Full Text Available Exocytosis is a fundamental cellular process whereby secreted molecules are packaged into vesicles that move along cytoskeletal filaments and fuse with the plasma membrane. To function optimally, cells are strongly dependent on precisely controlled delivery of exocytotic cargo. In mammalian cells, microtubules serve as major tracks for vesicle transport by motor proteins, and thus microtubule organization is important for targeted delivery of secretory carriers. Over the years, multiple microtubule-associated and cortical proteins have been discovered that facilitate the interaction between the microtubule plus ends and the cell cortex. In this review, we focus on mammalian protein complexes that have been shown to participate in both cortical microtubule capture and exocytosis, thereby regulating the spatial organization of secretion. These complexes include microtubule plus-end tracking proteins, scaffolding factors, actin-binding proteins, and components of vesicle docking machinery, which together allow efficient coordination of cargo transport and release.

  12. Connections underlying the synthesis of cognition, memory, and emotion in primate prefrontal cortices.

    Science.gov (United States)

    Barbas, H

    2000-07-15

    Distinct domains of the prefrontal cortex in primates have a set of connections suggesting that they have different roles in cognition, memory, and emotion. Caudal lateral prefrontal areas (areas 8 and 46) receive projections from cortices representing early stages in visual or auditory processing, and from intraparietal and posterior cingulate areas associated with oculomotor guidance and attentional processes. Cortical input to areas 46 and 8 is complemented by projections from the thalamic multiform and parvicellular sectors of the mediodorsal nucleus associated with oculomotor functions and working memory. In contrast, caudal orbitofrontal areas receive diverse input from cortices representing late stages of processing within every unimodal sensory cortical system. In addition, orbitofrontal and caudal medial (limbic) prefrontal cortices receive robust projections from the amygdala, associated with emotional memory, and from medial temporal and thalamic structures associated with long-term memory. Prefrontal cortices are linked with motor control structures related to their specific roles in central executive functions. Caudal lateral prefrontal areas project to brainstem oculomotor structures, and are connected with premotor cortices effecting head, limb and body movements. In contrast, medial prefrontal and orbitofrontal limbic cortices project to hypothalamic visceromotor centers for the expression of emotions. Lateral, orbitofrontal, and medial prefrontal cortices are robustly interconnected, suggesting that they participate in concert in central executive functions. Prefrontal limbic cortices issue widespread projections through their deep layers and terminate in the upper layers of lateral (eulaminate) cortices, suggesting a predominant role in feedback communication. In contrast, when lateral prefrontal cortices communicate with limbic areas they issue projections from their upper layers and their axons terminate in the deep layers, suggesting a role in

  13. Aerobic Fitness Linked to Cortical Brain Development in Adolescent Males: Preliminary Findings Suggest a Possible Role of BDNF Genotype.

    Science.gov (United States)

    Herting, Megan M; Keenan, Madison F; Nagel, Bonnie J

    2016-01-01

    Aerobic exercise has been shown to impact brain structure and cognition in children and adults. Exercise-induced activation of a growth protein known as brain derived neurotrophic factor (BDNF) is thought to contribute to such relationships. To date, however, no study has examined how aerobic fitness relates to cortical brain structure during development and if BDNF genotype moderates these relationships. Using structural magnetic resonance imaging (MRI) and FreeSurfer, the current study examined how aerobic fitness relates to volume, thickness, and surface area in 34 male adolescents, 15 to 18 years old. Moreover, we examined if the val66met BDNF genotype moderated these relationships. We hypothesized that aerobic fitness would relate to greater thickness and volumes in frontal, parietal, and motor regions, and that these relationships would be less robust in individuals carrying a Met allele, since this genotype leads to lower BDNF expression. We found that aerobic fitness positively related to right rostral middle frontal cortical volume in all adolescents. However, results also showed BDNF genotype moderated the relationship between aerobic fitness and bilateral medial precuneus surface area, with a positive relationship seen in individuals with the Val/Val allele, but no relationship detected in those adolescents carrying a Met allele. Lastly, using self-reported levels of aerobic activity, we found that higher-fit adolescents showed larger right medial pericalcarine, right cuneus and left precuneus surface areas as compared to their low-fit peers. Our findings suggest that aerobic fitness is linked to cortical brain development in male adolescents, and that more research is warranted to determine how an individual's genes may influence these relationships.

  14. Aerobic Fitness Linked to Cortical Brain Development in Adolescent Males: Preliminary Findings Suggest a Possible Role of BDNF Genotype

    Science.gov (United States)

    Herting, Megan M.; Keenan, Madison F.; Nagel, Bonnie J.

    2016-01-01

    Aerobic exercise has been shown to impact brain structure and cognition in children and adults. Exercise-induced activation of a growth protein known as brain derived neurotrophic factor (BDNF) is thought to contribute to such relationships. To date, however, no study has examined how aerobic fitness relates to cortical brain structure during development and if BDNF genotype moderates these relationships. Using structural magnetic resonance imaging (MRI) and FreeSurfer, the current study examined how aerobic fitness relates to volume, thickness, and surface area in 34 male adolescents, 15 to 18 years old. Moreover, we examined if the val66met BDNF genotype moderated these relationships. We hypothesized that aerobic fitness would relate to greater thickness and volumes in frontal, parietal, and motor regions, and that these relationships would be less robust in individuals carrying a Met allele, since this genotype leads to lower BDNF expression. We found that aerobic fitness positively related to right rostral middle frontal cortical volume in all adolescents. However, results also showed BDNF genotype moderated the relationship between aerobic fitness and bilateral medial precuneus surface area, with a positive relationship seen in individuals with the Val/Val allele, but no relationship detected in those adolescents carrying a Met allele. Lastly, using self-reported levels of aerobic activity, we found that higher-fit adolescents showed larger right medial pericalcarine, right cuneus and left precuneus surface areas as compared to their low-fit peers. Our findings suggest that aerobic fitness is linked to cortical brain development in male adolescents, and that more research is warranted to determine how an individual’s genes may influence these relationships. PMID:27445764

  15. Inverted Polarity Thunderstorms Linked with Elevated Cloud Base Height

    Science.gov (United States)

    Cummins, K. L.; Williams, E.

    2016-12-01

    The great majority of thunderstorms worldwide exhibit gross positive dipole structure, produce intracloud lightning that reduces this positive dipole (positive intracloud flashes), and produce negative cloud-to-ground lightning from the lower negative end of this dipole. During the STEPS experiment in 2000 much new evidence for thunderstorms (or cells within multi-cellular storms) with inverted polarity came to light, both from balloon soundings of electric field and from LMA analysis. Many of the storms with inverted polarity cells developed in eastern Colorado. Fleenor et al. (2009) followed up after STEPS to document a dominance of positive polarity CG lightning in many of these cases. In the present study, surface thermodynamic observations (temperature and dew point temperature) have been used to estimate the cloud base heights and temperatures at the time of the Fleenor et al. lightning observations. It was found that when more than 90% of the observed CG lightning polarity within a storm is negative, the cloud base heights were low (2000 m AGL or lower, and warmer, with T>10 C), and when more than 90% of the observed CG lightning within a storm was positive, the cloud base heights were high (3000 m AGL or higher, and colder, with Tmixed polarity were generally associated with intermediate cloud base heights. These findings on inverted polarity thunderstorms are remarkably consistent with results in other parts of the world where strong instability prevails in the presence of high cloud base height: the plateau regions of China (Liu et al., 1989; Qie et al., 2005), and in pre-monsoon India (Pawar et al., 2016), particularly when mixed polarity cases are excluded. Calculations of adiabatic cloud water content for lifting from near 0 oC cast some doubt on earlier speculation (Williams et al., 2005) that the graupel particles in these inverted polarity storms attain a wet growth condition, and so exhibit positive charging following laboratory experiments. This

  16. On the performance of telemedicine system using 17-GHz orthogonally polarized microwave links under the influence of heavy rainfall.

    Science.gov (United States)

    Fong, Bernard; Fong, A C M; Hong, G Y

    2005-09-01

    This paper describes the design of a telemedicine system based on next-generation wireless local area networks (WLANs) operating at 17 GHz. Seventeen gigahertz is proposed for next-generation WLAN services offering numerous advantages over traditional IEEE 802.11 networks that operate in the range of 2.4-5 GHz. Orthogonal polarization is often used to increase spectrum efficiency by utilizing signal paths of horizontal and vertical polarization. Radio waves exceeding 10 GHz are particularly vulnerable to signal degradation under the influence of rain which causes an effective reduction in isolation between polarized signal paths. This paper investigates the influence of heavy rain in a tropical region on wide-band microwave signals at 17 GHz using two links provided by a fixed broad-band wireless access system for two-way data exchange between paramedics attending an accident scene and the hospital via microwave equipment installed in the ambulance. We also study the effects of cross polarization and phase rotation due to persistent heavy rainfall in tropical regions.

  17. Human occipital cortices differentially exert saccadic suppression: intracranial recording in children

    Science.gov (United States)

    Uematsu, Mitsugu; Matsuzaki, Naoyuki; Brown, Erik C.; Kojima, Katsuaki; Asano, Eishi

    2013-01-01

    By repeating saccades unconsciously, humans explore the surrounding world every day. Saccades inevitably move external visual images across the retina at high velocity; nonetheless, healthy humans don’t perceive transient blurring of the visual scene during saccades. This perceptual stability is referred to as saccadic suppression. Functional suppression is believed to take place transiently in the visual systems, but it remains unknown how commonly or differentially the human occipital lobe activities are suppressed at the large-scale cortical network level. We determined the spatial-temporal dynamics of intracranially-recorded gamma activity at 80–150 Hz around spontaneous saccades under no-task conditions during wakefulness and those in darkness during REM sleep. Regardless of wakefulness or REM sleep, a small degree of attenuation of gamma activity was noted in the occipital regions during saccades, most extensively in the polar and least in the medial portions. Longer saccades were associated with more intense gamma-attenuation. Gamma-attenuation was subsequently followed by gamma-augmentation most extensively involving the medial and least involving the polar occipital region. Such gamma-augmentation was more intense during wakefulness and temporally locked to the offset of saccades. The polarities of initial peaks of perisaccadic event-related potentials (ERPs) were frequently positive in the medial and negative in the polar occipital regions. The present study, for the first time, provided the electrophysiological evidence that human occipital cortices differentially exert peri-saccadic modulation. Transiently suppressed sensitivity of the primary visual cortex in the polar region may be an important neural basis for saccadic suppression. Presence of occipital gamma-attenuation even during REM sleep suggests that saccadic suppression might be exerted even without external visual inputs. The primary visual cortex in the medial region, compared to the

  18. Spontaneously emerging cortical representations of visual attributes

    Science.gov (United States)

    Kenet, Tal; Bibitchkov, Dmitri; Tsodyks, Misha; Grinvald, Amiram; Arieli, Amos

    2003-10-01

    Spontaneous cortical activity-ongoing activity in the absence of intentional sensory input-has been studied extensively, using methods ranging from EEG (electroencephalography), through voltage sensitive dye imaging, down to recordings from single neurons. Ongoing cortical activity has been shown to play a critical role in development, and must also be essential for processing sensory perception, because it modulates stimulus-evoked activity, and is correlated with behaviour. Yet its role in the processing of external information and its relationship to internal representations of sensory attributes remains unknown. Using voltage sensitive dye imaging, we previously established a close link between ongoing activity in the visual cortex of anaesthetized cats and the spontaneous firing of a single neuron. Here we report that such activity encompasses a set of dynamically switching cortical states, many of which correspond closely to orientation maps. When such an orientation state emerged spontaneously, it spanned several hypercolumns and was often followed by a state corresponding to a proximal orientation. We suggest that dynamically switching cortical states could represent the brain's internal context, and therefore reflect or influence memory, perception and behaviour.

  19. Detecting a cortical fingerprint of Parkinson’s disease for closed-loop neuromodulation

    Directory of Open Access Journals (Sweden)

    Kevin eKern

    2016-03-01

    Full Text Available Recent evidence suggests that deep brain stimulation (DBS of the subthalamic nucleus (STN in Parkinson’s disease (PD mediates its clinical effects by modulating cortical oscillatory activity, presumably via a direct cortico-subthalamic connection. This observation might pave the way for novel closed-loop approaches comprising a cortical sensor. Enhanced beta oscillations (13-35 Hz have been linked to the pathophysiology of PD and may serve as such a candidate marker to localize a cortical area reliably modulated by DBS. However, beta-oscillations are widely distributed over the cortical surface, necessitating an additional signal source for spotting the cortical area linked to the pathologically synchronized cortico-subcortical motor network.In this context, both cortico-subthalamic coherence and cortico-muscular coherence (CMC have been studied in PD patients. Whereas the former requires invasive recordings, the latter allows for non-invasive detection, but displays a rather distributed cortical synchronization pattern in motor tasks. This distributed cortical representation may conflict with the goal of detecting a cortical localization with robust biomarker properties which is detectable on a single subject basis. We propose that this limitation could be overcome when recording CMC at rest. We hypothesized that – unlike healthy subjects – PD would show CMC at rest owing to the enhanced beta oscillations observed in PD. By performing source space analysis of beta CMC recorded during resting-state magnetoencephalography, we provide preliminary evidence in one patient for a cortical hot spot that is modulated most strongly by subthalamic DBS. Such a spot would provide a prominent target region either for direct neuromodulation or for placing a potential sensor in closed-loop DBS approaches, a proposal that requires investigation in a larger cohort of PD patients.

  20. Cortical Thickness Changes Associated with Photoparoxysmal Response

    DEFF Research Database (Denmark)

    Hanganu, Alexandru; Groppa, Stanislav A; Deuschl, Günther

    2014-01-01

    Photoparoxysmal response (PPR) is an EEG trait of spike and spike-wave discharges in response to photic stimulation that is closely linked to idiopathic generalized epilepsy (IGE). In our previous studies we showed that PPR is associated with functional alterations in the occipital and frontal co...... in the occipital lobe, frontoparietal regions and temporal lobe, which also show functional changes associated with PPR. Patients with epilepsy present changes in the temporal lobe and supplementary motor area.......-positive-subjects presented a significant decrease of cortical thickness in the temporal cortex in the same group contrast. IGE patients exhibited lower cortical thickness in the temporal lobe bilaterally and in the right paracentral region in comparison to PPR-positive-subjects. Our study demonstrates structural changes......Photoparoxysmal response (PPR) is an EEG trait of spike and spike-wave discharges in response to photic stimulation that is closely linked to idiopathic generalized epilepsy (IGE). In our previous studies we showed that PPR is associated with functional alterations in the occipital and frontal...

  1. The Use of Orthogonal Polarizations in Microwave Imagery of Isolated Canine Kidney

    Science.gov (United States)

    Larsen, L. E.; Jacobi, J. H.

    1980-06-01

    A method of imaging biological targets using microwave radiation at a frequency of 4 GHz is presented. Linearly polarized radiation is transmitted through an isolated canine kidney and received with co-polarized and cross-polarized antennas. Images are displayed as the spatial variation of the magnitude of the transmission scattering parameter S21 for each mode of polarization. The relationship between the spatial variation of the magnitude of S21 and canine renal anatomy is discussed. It is shown that within the kidney the cross-polarized image tends to emphasize linear or piecewise linear structures, whereas the co-polarized image balances renal cortical lobulations.

  2. Histomorphometry and cortical robusticity of the adult human femur.

    Science.gov (United States)

    Miszkiewicz, Justyna Jolanta; Mahoney, Patrick

    2018-01-13

    Recent quantitative analyses of human bone microanatomy, as well as theoretical models that propose bone microstructure and gross anatomical associations, have started to reveal insights into biological links that may facilitate remodeling processes. However, relationships between bone size and the underlying cortical bone histology remain largely unexplored. The goal of this study is to determine the extent to which static indicators of bone remodeling and vascularity, measured using histomorphometric techniques, relate to femoral midshaft cortical width and robusticity. Using previously published and new quantitative data from 450 adult human male (n = 233) and female (n = 217) femora, we determine if these aspects of femoral size relate to bone microanatomy. Scaling relationships are explored and interpreted within the context of tissue form and function. Analyses revealed that the area and diameter of Haversian canals and secondary osteons, and densities of secondary osteons and osteocyte lacunae from the sub-periosteal region of the posterior midshaft femur cortex were significantly, but not consistently, associated with femoral size. Cortical width and bone robusticity were correlated with osteocyte lacunae density and scaled with positive allometry. Diameter and area of osteons and Haversian canals decreased as the width of cortex and bone robusticity increased, revealing a negative allometric relationship. These results indicate that microscopic products of cortical bone remodeling and vascularity are linked to femur size. Allometric relationships between more robust human femora with thicker cortical bone and histological products of bone remodeling correspond with principles of bone functional adaptation. Future studies may benefit from exploring scaling relationships between bone histomorphometric data and measurements of bone macrostructure.

  3. Ultrasonically-induced electrical potentials in demineralized bovine cortical bone

    Science.gov (United States)

    Mori, Shunki; Makino, Taiki; Koyama, Daisuke; Takayanagi, Shinji; Yanagitani, Takahiko; Matsukawa, Mami

    2018-04-01

    While the low-intensity pulsed ultrasound technique has proved useful for healing of bone fractures, the ultrasound healing mechanism is not yet understood. To understand the initial physical effects of the ultrasound irradiation process on bone, we have studied the anisotropic piezoelectric properties of bone in the MHz range. Bone is known to be composed of collagen and hydroxyapatite (HAp) and shows strong elastic anisotropy. In this study, the effects of HAp on the piezoelectricity were investigated experimentally. To remove the HAp crystallites from the bovine cortical bone, demineralization was performed using ethylene diamine tetra-acetic acid (EDTA) solutions. To investigate the piezoelectricity, we have fabricated ultrasound transducers using the cortical bone or demineralized cortical bone. The induced electrical potentials due to the piezoelectricity were observed as the output of these transducers under pulsed ultrasound irradiation in the MHz range. The cortical bone transducer (before mineralization) showed anisotropic piezoelectric behavior. When the ultrasound irradiation was applied normal to the transducer surface, the observed induced electrical potentials had minimum values. The potential increased under off-axis ultrasound irradiation with changes in polarization. In the demineralized bone transducer case, however, the anisotropic behavior was not observed in the induced electrical potentials. These results therefore indicate that the HAp crystallites affect the piezoelectric characteristics of bone.

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

    Science.gov (United States)

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

    2014-10-15

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

  5. Self-Referential Processing, Rumination, and Cortical Midline Structures in Major Depression

    Science.gov (United States)

    Nejad, Ayna Baladi; Fossati, Philippe; Lemogne, Cédric

    2013-01-01

    Major depression is associated with a bias toward negative emotional processing and increased self-focus, i.e., the process by which one engages in self-referential processing. The increased self-focus in depression is suggested to be of a persistent, repetitive and self-critical nature, and is conceptualized as ruminative brooding. The role of the medial prefrontal cortex in self-referential processing has been previously emphasized in acute major depression. There is increasing evidence that self-referential processing as well as the cortical midline structures play a major role in the development, course, and treatment response of major depressive disorder. However, the links between self-referential processing, rumination, and the cortical midline structures in depression are still poorly understood. Here, we reviewed brain imaging studies in depressed patients and healthy subjects that have examined these links. Self-referential processing in major depression seems associated with abnormally increased activity of the anterior cortical midline structures. Abnormal interactions between the lateralized task-positive network, and the midline cortical structures of the default mode network, as well as the emotional response network, may underlie the pervasiveness of ruminative brooding. Furthermore, targeting this maladaptive form of rumination and its underlying neural correlates may be key for effective treatment. PMID:24124416

  6. Self-referential processing, rumination, and cortical midline structures in major depression

    Directory of Open Access Journals (Sweden)

    Ayna Baladi Nejad

    2013-10-01

    Full Text Available Major depression is associated with a bias towards negative emotional processing and increased self-focus, i.e. the process by which one engages in self-referential processing. The increased self-focus in depression is suggested to be of a persistent, repetitive and self-critical nature and is conceptualised as ruminative brooding. The role of the medial prefrontal cortex in self-referential processing has been previously emphasised in acute major depression. There is increasing evidence that self-referential processing as well as the cortical midline structures play a major role in the development, course and treatment response of major depressive disorder. However, the links between self-referential processing, rumination, and the cortical midline structures in depression are still poorly understood. Here, we reviewed brain imaging studies in depressed patients and healthy subjects that have examined these links. The literature suggests that self-referential processing in major depression is associated with increased activity of the anterior cortical midline structures. Abnormal interactions between the lateralised task-positive network, and the midline cortical structures of the default mode network, as well as the emotional response network, may underlie the pervasiveness of ruminative brooding. Furthermore, targeting this maladaptive form of rumination and its underlying neural correlates may be key for effective treatment.

  7. Identification of a brainstem circuit regulating visual cortical state in parallel with locomotion.

    Science.gov (United States)

    Lee, A Moses; Hoy, Jennifer L; Bonci, Antonello; Wilbrecht, Linda; Stryker, Michael P; Niell, Cristopher M

    2014-07-16

    Sensory processing is dependent upon behavioral state. In mice, locomotion is accompanied by changes in cortical state and enhanced visual responses. Although recent studies have begun to elucidate intrinsic cortical mechanisms underlying this effect, the neural circuits that initially couple locomotion to cortical processing are unknown. The mesencephalic locomotor region (MLR) has been shown to be capable of initiating running and is associated with the ascending reticular activating system. Here, we find that optogenetic stimulation of the MLR in awake, head-fixed mice can induce both locomotion and increases in the gain of cortical responses. MLR stimulation below the threshold for overt movement similarly changed cortical processing, revealing that MLR's effects on cortex are dissociable from locomotion. Likewise, stimulation of MLR projections to the basal forebrain also enhanced cortical responses, suggesting a pathway linking the MLR to cortex. These studies demonstrate that the MLR regulates cortical state in parallel with locomotion. Copyright © 2014 Elsevier Inc. All rights reserved.

  8. The relationship of rain-induced cross-polarization discrimination to attenuation for 10 to 30 GHz earth-space radio links

    Science.gov (United States)

    Stutzman, W. L.; Runyon, D. L.

    1984-01-01

    Rain depolarization is quantified through the cross-polarization discrimination (XPD) versus attenuation relationship. Such a relationship is derived by curve fitting to a rigorous theoretical model (the multiple scattering model) to determine the variation of the parameters involved. This simple isolation model (SIM) is compared to data from several earth-space link experiments and to three other models.

  9. Prefrontal cortical gamma-aminobutyric acid transmission and cognitive function: drawing links to schizophrenia from preclinical research.

    Science.gov (United States)

    Tse, Maric T; Piantadosi, Patrick T; Floresco, Stan B

    2015-06-01

    Cognitive dysfunction in schizophrenia is one of the most pervasive and debilitating aspects of the disorder. Among the numerous neural abnormalities that may contribute to schizophrenia symptoms, perturbations in markers for the inhibitory neurotransmitter gamma-aminobutyric acid (GABA), particularly within the frontal lobes, are some of the most reliable alterations observed at postmortem examination. However, how prefrontal GABA dysfunction contributes to cognitive impairment in schizophrenia remains unclear. We provide an overview of postmortem GABAergic perturbations in the brain affected by schizophrenia and describe circumstantial evidence linking these alterations to cognitive dysfunction. In addition, we conduct a survey of studies using neurodevelopmental, genetic, and pharmacologic rodent models that induce schizophrenia-like cognitive impairments, highlighting the convergence of these mechanistically distinct approaches to prefrontal GABAergic disruption. We review preclinical studies that have directly targeted prefrontal cortical GABAergic transmission using local application of GABAA receptor antagonists. These studies have provided an important link between GABA transmission and cognitive dysfunction in schizophrenia because they show that reducing prefrontal inhibitory transmission induces various cognitive, emotional, and dopaminergic abnormalities that resemble aspects of the disorder. These converging clinical and preclinical findings provide strong support for the idea that perturbations in GABA signaling drive certain forms of cognitive dysfunction in schizophrenia. Future studies using this approach will yield information to refine further a putative "GABA hypothesis" of schizophrenia. Copyright © 2015 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

  10. Motor activation in SPG4-linked hereditary spastic paraplegia

    DEFF Research Database (Denmark)

    Scheuer, KH; Nielsen, JE; Krabbe, Katja

    2006-01-01

    OBJECTIVE: The aim of this study was to investigate the extent of motor cortical functional reorganisation in patients with SPG4-linked hereditary spastic paraplegia by exploring cortical motor activation related to movements of clinically affected (lower) and unaffected (upper) limbs. METHODS: T...

  11. Periventricular Heterotopia: Shuttling of Proteins through Vesicles and Actin in Cortical Development and Disease

    Directory of Open Access Journals (Sweden)

    Volney L. Sheen

    2012-01-01

    Full Text Available During cortical development, proliferating neural progenitors exhibit polarized apical and basolateral membranes that are maintained by tightly controlled and membrane-specific vesicular trafficking pathways. Disruption of polarity through impaired delivery of proteins can alter cell fate decisions and consequent expansion of the progenitor pool, as well as impact the integrity of the neuroependymal lining. Loss of neuroependymal integrity disrupts radial glial scaffolding and alters initial neuronal migration from the ventricular zone. Vesicle trafficking is also required for maintenance of lipid and protein cycling within the leading and trailing edge of migratory neurons, as well as dendrites and synapses of mature neurons. Defects in this transport machinery disrupt neuronal identity, migration, and connectivity and give rise to a malformation of cortical development termed as periventricular heterotopia (PH. PH is characterized by a reduction in brain size, ectopic clusters of neurons localized along the lateral ventricle, and epilepsy and dyslexia. These anatomical anomalies correlate with developmental impairments in neural progenitor proliferation and specification, migration from loss of neuroependymal integrity and neuronal motility, and aberrant neuronal process extension. Genes causal for PH regulate vesicle-mediated endocytosis along an actin cytoskeletal network. This paper explores the role of these dynamic processes in cortical development and disease.

  12. [Cortical functional connectivity during retention of affective pictures in working memory: EEG-source theta coherence analysis].

    Science.gov (United States)

    Machinskaya, R I; Rozovskaya, R I; Kurgansky, A V; Pechenkova, E V

    2016-01-01

    A pattern of cortical functional connectivity in the source space was studied in a group of right-handed adult participants (N = 44:17 women, 27 men, aged M = 29.61 ± 6.45 years) who retained in their working memory (WM) traces of realistic pictures of positive, neutral, and negative emotional valence while in their working memory (WM) while performing same different task in which participants had to compare an etalon picture against a target picture that followed after a specified delay. A coherence (COH) between pairs of cortical sources chosen in advance according to fMRI data was estimated in the theta frequency range for the period of time preceding the etalon stimulus, distinct sets of functional links are found. The links of the first type that presumably reflect the involvement of sustained attention were between the dorsal anterior cingulate cortex, the prefrontal areas, and temporal areas of the right hemispheres. When compared to the rest period, links of this type showed strengthening not only during the retention period but also during the period preceding the etalon picture. The links of the second type presumably reflecting a progressive neocortex-to-hippocampus functional integration with increasing memory load and strengthened exclusively during retention period. Those links were between parietal, temporal and prefrontal cortices in the lateral surface of both hemispheres with the additional inclusion of the posterior cingulate cortex and the medial parietal cortex in the left hemisphere. An impact of emotional valence onto the strength and topography of the functional links of the second type was found. In the left hemisphere, an increase in the strength of cortical interaction was more pronounced for pictures of positive valence than for pictures of either neutral or negative valences. When compared to the pictures of neutral valence, the retention of pictorial information of both positive and negative valence showed some extraneous integration

  13. Cortical entrainment to music and its modulation by expertise.

    Science.gov (United States)

    Doelling, Keith B; Poeppel, David

    2015-11-10

    Recent studies establish that cortical oscillations track naturalistic speech in a remarkably faithful way. Here, we test whether such neural activity, particularly low-frequency (music and whether experience modifies such a cortical phenomenon. Music of varying tempi was used to test entrainment at different rates. In three magnetoencephalography experiments, we recorded from nonmusicians, as well as musicians with varying years of experience. Recordings from nonmusicians demonstrate cortical entrainment that tracks musical stimuli over a typical range of tempi, but not at tempi below 1 note per second. Importantly, the observed entrainment correlates with performance on a concurrent pitch-related behavioral task. In contrast, the data from musicians show that entrainment is enhanced by years of musical training, at all presented tempi. This suggests a bidirectional relationship between behavior and cortical entrainment, a phenomenon that has not previously been reported. Additional analyses focus on responses in the beta range (∼15-30 Hz)-often linked to delta activity in the context of temporal predictions. Our findings provide evidence that the role of beta in temporal predictions scales to the complex hierarchical rhythms in natural music and enhances processing of musical content. This study builds on important findings on brainstem plasticity and represents a compelling demonstration that cortical neural entrainment is tightly coupled to both musical training and task performance, further supporting a role for cortical oscillatory activity in music perception and cognition.

  14. Neural coding of image structure and contrast polarity of Cartesian, hyperbolic, and polar gratings in the primary and secondary visual cortex of the tree shrew.

    Science.gov (United States)

    Poirot, Jordan; De Luna, Paolo; Rainer, Gregor

    2016-04-01

    We comprehensively characterize spiking and visual evoked potential (VEP) activity in tree shrew V1 and V2 using Cartesian, hyperbolic, and polar gratings. Neural selectivity to structure of Cartesian gratings was higher than other grating classes in both visual areas. From V1 to V2, structure selectivity of spiking activity increased, whereas corresponding VEP values tended to decrease, suggesting that single-neuron coding of Cartesian grating attributes improved while the cortical columnar organization of these neurons became less precise from V1 to V2. We observed that neurons in V2 generally exhibited similar selectivity for polar and Cartesian gratings, suggesting that structure of polar-like stimuli might be encoded as early as in V2. This hypothesis is supported by the preference shift from V1 to V2 toward polar gratings of higher spatial frequency, consistent with the notion that V2 neurons encode visual scene borders and contours. Neural sensitivity to modulations of polarity of hyperbolic gratings was highest among all grating classes and closely related to the visual receptive field (RF) organization of ON- and OFF-dominated subregions. We show that spatial RF reconstructions depend strongly on grating class, suggesting that intracortical contributions to RF structure are strongest for Cartesian and polar gratings. Hyperbolic gratings tend to recruit least cortical elaboration such that the RF maps are similar to those generated by sparse noise, which most closely approximate feedforward inputs. Our findings complement previous literature in primates, rodents, and carnivores and highlight novel aspects of shape representation and coding occurring in mammalian early visual cortex. Copyright © 2016 the American Physiological Society.

  15. Impact of prenatal environmental stress on cortical development

    Directory of Open Access Journals (Sweden)

    Seiji eIshii

    2015-05-01

    Full Text Available Prenatal exposure of the developing brain to various types of environmental stress increases susceptibility to neuropsychiatric disorders such as autism, attention deficit hyperactivity disorder and schizophrenia. Given that even subtle perturbations by prenatal environmental stress in the cerebral cortex impair the cognitive and memory functions, this review focuses on underlying molecular mechanisms of pathological cortical development. We especially highlight recent works that utilized animal exposure models, human specimens or/and induced Pluripotent Stem (iPS cells to demonstrate: 1. molecular mechanisms shared by various types of environmental stressors, 2. the mechanisms by which the affected extracortical tissues indirectly impact the cortical development and function, and 3. interaction between prenatal environmental stress and the genetic predisposition of neuropsychiatric disorders. Finally, we discuss current challenges for achieving a comprehensive understanding of the role of environmentally disturbed molecular expressions in cortical maldevelopment, knowledge of which may eventually facilitate discovery of interventions for prenatal environment-linked neuropsychiatric disorders.

  16. Cortical Spreading Depression Closes Paravascular Space and Impairs Glymphatic Flow: Implications for Migraine Headache.

    Science.gov (United States)

    Schain, Aaron J; Melo-Carrillo, Agustin; Strassman, Andrew M; Burstein, Rami

    2017-03-15

    Functioning of the glymphatic system, a network of paravascular tunnels through which cortical interstitial solutes are cleared from the brain, has recently been linked to sleep and traumatic brain injury, both of which can affect the progression of migraine. This led us to investigate the connection between migraine and the glymphatic system. Taking advantage of a novel in vivo method we developed using two-photon microscopy to visualize the paravascular space (PVS) in naive uninjected mice, we show that a single wave of cortical spreading depression (CSD), an animal model of migraine aura, induces a rapid and nearly complete closure of the PVS around surface as well as penetrating cortical arteries and veins lasting several minutes, and gradually recovering over 30 min. A temporal mismatch between the constriction or dilation of the blood vessel lumen and the closure of the PVS suggests that this closure is not likely to result from changes in vessel diameter. We also show that CSD impairs glymphatic flow, as indicated by the reduced rate at which intraparenchymally injected dye was cleared from the cortex to the PVS. This is the first observation of a PVS closure in connection with an abnormal cortical event that underlies a neurological disorder. More specifically, the findings demonstrate a link between the glymphatic system and migraine, and suggest a novel mechanism for regulation of glymphatic flow. SIGNIFICANCE STATEMENT Impairment of brain solute clearance through the recently described glymphatic system has been linked with traumatic brain injury, prolonged wakefulness, and aging. This paper shows that cortical spreading depression, the neural correlate of migraine aura, closes the paravascular space and impairs glymphatic flow. This closure holds the potential to define a novel mechanism for regulation of glymphatic flow. It also implicates the glymphatic system in the altered cortical and endothelial functioning of the migraine brain. Copyright © 2017

  17. Alterations of cortical GABA neurons and network oscillations in schizophrenia.

    Science.gov (United States)

    Gonzalez-Burgos, Guillermo; Hashimoto, Takanori; Lewis, David A

    2010-08-01

    The hypothesis that alterations of cortical inhibitory gamma-aminobutyric acid (GABA) neurons are a central element in the pathology of schizophrenia has emerged from a series of postmortem studies. How such abnormalities may contribute to the clinical features of schizophrenia has been substantially informed by a convergence with basic neuroscience studies revealing complex details of GABA neuron function in the healthy brain. Importantly, activity of the parvalbumin-containing class of GABA neurons has been linked to the production of cortical network oscillations. Furthermore, growing knowledge supports the concept that gamma band oscillations (30-80 Hz) are an essential mechanism for cortical information transmission and processing. Herein we review recent studies further indicating that inhibition from parvalbumin-positive GABA neurons is necessary to produce gamma oscillations in cortical circuits; provide an update on postmortem studies documenting that deficits in the expression of glutamic acid decarboxylase67, which accounts for most GABA synthesis in the cortex, are widely observed in schizophrenia; and describe studies using novel, noninvasive approaches directly assessing potential relations between alterations in GABA, oscillations, and cognitive function in schizophrenia.

  18. Cortical visual impairment

    OpenAIRE

    Koželj, Urša

    2013-01-01

    In this thesis we discuss cortical visual impairment, diagnosis that is in the developed world in first place, since 20 percent of children with blindness or low vision are diagnosed with it. The objectives of the thesis are to define cortical visual impairment and the definition of characters suggestive of the cortical visual impairment as well as to search for causes that affect the growing diagnosis of cortical visual impairment. There are a lot of signs of cortical visual impairment. ...

  19. Effects of Habitual Physical Activity and Fitness on Tibial Cortical Bone Mass, Structure and Mass Distribution in Pre-pubertal Boys and Girls: The Look Study.

    Science.gov (United States)

    Duckham, Rachel L; Rantalainen, Timo; Ducher, Gaele; Hill, Briony; Telford, Richard D; Telford, Rohan M; Daly, Robin M

    2016-07-01

    Targeted weight-bearing activities during the pre-pubertal years can improve cortical bone mass, structure and distribution, but less is known about the influence of habitual physical activity (PA) and fitness. This study examined the effects of contrasting habitual PA and fitness levels on cortical bone density, geometry and mass distribution in pre-pubertal children. Boys (n = 241) and girls (n = 245) aged 7-9 years had a pQCT scan to measure tibial mid-shaft total, cortical and medullary area, cortical thickness, density, polar strength strain index (SSIpolar) and the mass/density distribution through the bone cortex (radial distribution divided into endo-, mid- and pericortical regions) and around the centre of mass (polar distribution). Four contrasting PA and fitness groups (inactive-unfit, inactive-fit, active-unfit, active-fit) were generated based on daily step counts (pedometer, 7-days) and fitness levels (20-m shuttle test and vertical jump) for boys and girls separately. Active-fit boys had 7.3-7.7 % greater cortical area and thickness compared to inactive-unfit boys (P girls, but active-fit girls had 6.1 % (P girls, which was likely due to their 6.7 % (P active-fit girls. Higher levels of habitual PA-fitness were associated with small regional-specific gains in 66 % tibial cortical bone mass in pre-pubertal children, particularly boys.

  20. Dendritic nonlinearities are tuned for efficient spike-based computations in cortical circuits.

    Science.gov (United States)

    Ujfalussy, Balázs B; Makara, Judit K; Branco, Tiago; Lengyel, Máté

    2015-12-24

    Cortical neurons integrate thousands of synaptic inputs in their dendrites in highly nonlinear ways. It is unknown how these dendritic nonlinearities in individual cells contribute to computations at the level of neural circuits. Here, we show that dendritic nonlinearities are critical for the efficient integration of synaptic inputs in circuits performing analog computations with spiking neurons. We developed a theory that formalizes how a neuron's dendritic nonlinearity that is optimal for integrating synaptic inputs depends on the statistics of its presynaptic activity patterns. Based on their in vivo preynaptic population statistics (firing rates, membrane potential fluctuations, and correlations due to ensemble dynamics), our theory accurately predicted the responses of two different types of cortical pyramidal cells to patterned stimulation by two-photon glutamate uncaging. These results reveal a new computational principle underlying dendritic integration in cortical neurons by suggesting a functional link between cellular and systems--level properties of cortical circuits.

  1. Investigations of Polarization Dependent Loss in Polarization Modulated Analog Optical Links

    Science.gov (United States)

    2015-12-29

    performance analog optical links for military applications primarily rely on the most common link architecture employing intensity modulation with...axis as bisector of DD and Ss•) PP = fl i p ( rr, PPO] ; (• flip the P vector imaqe on the PA •) PPh a t = unit[PP ) ; PHI = ArcCos [ PPha t .unit...DD ) ); AA = ((Cos ( PHI / 2])𔃼 • t p (Sin [ PHI / 2 ])𔃼 ) PP • tpDDhat / 2 ; CC2 =- ( MM · AA . SS • (AA . I!M) (I!M. SS)) ; CC3 = AA . SS; ln

  2. The Unique Brain Anatomy of Meditation Practitioners: Alterations in Cortical Gyrification

    Science.gov (United States)

    Luders, Eileen; Kurth, Florian; Mayer, Emeran A.; Toga, Arthur W.; Narr, Katherine L.; Gaser, Christian

    2012-01-01

    links between cortical gyrification and meditation. PMID:22393318

  3. Investigations in Satellite MIMO Channel Modeling: Accent on Polarization

    Directory of Open Access Journals (Sweden)

    Karagiannidis George K

    2007-01-01

    Full Text Available Due to the much different environment in satellite and terrestrial links, possibilities in and design of MIMO systems are rather different as well. After pointing out these differences and problems arising from them, two MIMO designs are shown rather well adapted to satellite link characteristics. Cooperative diversity seems to be applicable; its concept is briefly presented without a detailed discussion, leaving solving particular satellite problems to later work. On the other hand, a detailed discussion of polarization time-coded diversity (PTC is given. A physical-statistical model for dual-polarized satellite links is presented together with measuring results validating the model. The concept of 3D polarization is presented as well as briefly describing compact 3D-polarized antennas known from the literature and applicable in satellite links. A synthetic satellite-to-indoor link is constructed and its electromagnetic behavior is simulated via the FDTD (finite-difference time-domain method. Previous result of the authors states that in 3D-PTC situations, MIMO capacity can be about two times higher than SIMO (single-input multiple-output capacity while a diversity gain of nearly is further verified via extensive FDTD computer simulation.

  4. Functional neural substrates of posterior cortical atrophy patients.

    Science.gov (United States)

    Shames, H; Raz, N; Levin, Netta

    2015-07-01

    Posterior cortical atrophy (PCA) is a neurodegenerative syndrome in which the most pronounced pathologic involvement is in the occipito-parietal visual regions. Herein, we aimed to better define the cortical reflection of this unique syndrome using a thorough battery of behavioral and functional MRI (fMRI) tests. Eight PCA patients underwent extensive testing to map their visual deficits. Assessments included visual functions associated with lower and higher components of the cortical hierarchy, as well as dorsal- and ventral-related cortical functions. fMRI was performed on five patients to examine the neuronal substrate of their visual functions. The PCA patient cohort exhibited stereopsis, saccadic eye movements and higher dorsal stream-related functional impairments, including simultant perception, image orientation, figure-from-ground segregation, closure and spatial orientation. In accordance with the behavioral findings, fMRI revealed intact activation in the ventral visual regions of face and object perception while more dorsal aspects of perception, including motion and gestalt perception, revealed impaired patterns of activity. In most of the patients, there was a lack of activity in the word form area, which is known to be linked to reading disorders. Finally, there was evidence of reduced cortical representation of the peripheral visual field, corresponding to the behaviorally assessed peripheral visual deficit. The findings are discussed in the context of networks extending from parietal regions, which mediate navigationally related processing, visually guided actions, eye movement control and working memory, suggesting that damage to these networks might explain the wide range of deficits in PCA patients.

  5. Using modern human cortical bone distribution to test the systemic robusticity hypothesis.

    Science.gov (United States)

    Baab, Karen L; Copes, Lynn E; Ward, Devin L; Wells, Nora; Grine, Frederick E

    2018-06-01

    The systemic robusticity hypothesis links the thickness of cortical bone in both the cranium and limb bones. This hypothesis posits that thick cortical bone is in part a systemic response to circulating hormones, such as growth hormone and thyroid hormone, possibly related to physical activity or cold climates. Although this hypothesis has gained popular traction, only rarely has robusticity of the cranium and postcranial skeleton been considered jointly. We acquired computed tomographic scans from associated crania, femora and humeri from single individuals representing 11 populations in Africa and North America (n = 228). Cortical thickness in the parietal, frontal and occipital bones and cortical bone area in limb bone diaphyses were analyzed using correlation, multiple regression and general linear models to test the hypothesis. Absolute thickness values from the crania were not correlated with cortical bone area of the femur or humerus, which is at odds with the systemic robusticity hypothesis. However, measures of cortical bone scaled by total vault thickness and limb cross-sectional area were positively correlated between the cranium and postcranium. When accounting for a range of potential confounding variables, including sex, age and body mass, variation in relative postcranial cortical bone area explained ∼20% of variation in the proportion of cortical cranial bone thickness. While these findings provide limited support for the systemic robusticity hypothesis, cranial cortical thickness did not track climate or physical activity across populations. Thus, some of the variation in cranial cortical bone thickness in modern humans is attributable to systemic effects, but the driving force behind this effect remains obscure. Moreover, neither absolute nor proportional measures of cranial cortical bone thickness are positively correlated with total cranial bone thickness, complicating the extrapolation of these findings to extinct species where only cranial

  6. Identification of an O-linked repetitive glycan chain of the polar flagellum flagellin of Azospirillum brasilense Sp7.

    Science.gov (United States)

    Belyakov, Alexei Ye; Burygin, Gennady L; Arbatsky, Nikolai P; Shashkov, Alexander S; Selivanov, Nikolai Yu; Matora, Larisa Yu; Knirel, Yuriy A; Shchyogolev, Sergei Yu

    2012-11-01

    This is the first report to have identified an O-linked repetitive glycan in bacterial flagellin, a structural protein of the flagellum. Studies by sugar analysis, Smith degradation, (1)H and (13)C NMR spectroscopy, and mass spectrometry showed that the glycan chains of the polar flagellum flagellin of the plant-growth-promoting rhizobacterium Azospirillum brasilense Sp7 are represented by a polysaccharide with a molecular mass of 7.7 kDa, which has a branched tetrasaccharide repeating unit of the following structure: Copyright © 2012. Published by Elsevier Ltd.

  7. Repair of Neocortex in a Model of Cortical Dysplasia

    Science.gov (United States)

    2007-03-27

    as dyslexia, intractable epilepsy, and schizophrenia which has been linked to abnormal reelin expression (Grayson et al., 2005; Brigman et al., 2006...exposure to ethanol on glutamate and GABA immunoreactivity in macaque somatosensory and motor cortices: critical timing of exposure. Neuroscience...Rothblat LA (2006) Executive functions in the heterozygous reeler mouse model of schizophrenia . Behav Neurosci 120:984-988. Caldwell MA, He X

  8. Llgl1 Connects Cell Polarity with Cell-Cell Adhesion in Embryonic Neural Stem Cells.

    Science.gov (United States)

    Jossin, Yves; Lee, Minhui; Klezovitch, Olga; Kon, Elif; Cossard, Alexia; Lien, Wen-Hui; Fernandez, Tania E; Cooper, Jonathan A; Vasioukhin, Valera

    2017-06-05

    Malformations of the cerebral cortex (MCCs) are devastating developmental disorders. We report here that mice with embryonic neural stem-cell-specific deletion of Llgl1 (Nestin-Cre/Llgl1 fl/fl ), a mammalian ortholog of the Drosophila cell polarity gene lgl, exhibit MCCs resembling severe periventricular heterotopia (PH). Immunohistochemical analyses and live cortical imaging of PH formation revealed that disruption of apical junctional complexes (AJCs) was responsible for PH in Nestin-Cre/Llgl1 fl/fl brains. While it is well known that cell polarity proteins govern the formation of AJCs, the exact mechanisms remain unclear. We show that LLGL1 directly binds to and promotes internalization of N-cadherin, and N-cadherin/LLGL1 interaction is inhibited by atypical protein kinase C-mediated phosphorylation of LLGL1, restricting the accumulation of AJCs to the basolateral-apical boundary. Disruption of the N-cadherin-LLGL1 interaction during cortical development in vivo is sufficient for PH. These findings reveal a mechanism responsible for the physical and functional connection between cell polarity and cell-cell adhesion machineries in mammalian cells. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. Cortical tremor: a variant of cortical reflex myoclonus.

    Science.gov (United States)

    Ikeda, A; Kakigi, R; Funai, N; Neshige, R; Kuroda, Y; Shibasaki, H

    1990-10-01

    Two patients with action tremor that was thought to originate in the cerebral cortex showed fine shivering-like finger twitching provoked mainly by action and posture. Surface EMG showed relatively rhythmic discharge at a rate of about 9 Hz, which resembled essential tremor. However, electrophysiologic studies revealed giant somatosensory evoked potentials (SEPs) with enhanced long-loop reflex and premovement cortical spike by the jerk-locked averaging method. Treatment with beta-blocker showed no effect, but anticonvulsants such as clonazepam, valproate, and primidone were effective to suppress the tremor and the amplitude of SEPs. We call this involuntary movement "cortical tremor," which is in fact a variant of cortical reflex myoclonus.

  10. Cortical thickness, surface area, and folding alterations in male youths with conduct disorder and varying levels of callous–unemotional traits

    Directory of Open Access Journals (Sweden)

    Graeme Fairchild

    2015-01-01

    Conclusions: Cortical thinning in the superior temporal gyrus may contribute to the social cognitive impairments displayed by youths with CD, whereas reduced OFC SA may lead to impairments in emotion regulation and reward processing in youths with CD. The increased cortical folding observed in the insula may reflect a maturational delay in this region and could mediate the link between CU traits and empathy deficits. Altered cortical folding was observed in childhood-onset and adolescence-onset forms of CD.

  11. The polar mesosphere

    International Nuclear Information System (INIS)

    Morris, Ray; Murphy, Damian

    2008-01-01

    The mesosphere region, which lies at the edge of space, contains the coldest layer of the Earth's atmosphere, with summer temperatures as low as minus 130 °C. In this extreme environment ice aerosol layers have appeared since the dawn of industrialization—whose existence may arguably be linked to human influence—on yet another layer of the Earth's fragile atmosphere. Ground-based and space-based experiments conducted in the Arctic and Antarctic during the International Polar Year (IPY) aim to address limitations in our knowledge and to advance our understanding of thermal and dynamical processes at play in the polar mesosphere

  12. Extent of cortical involvement in amyotrophic lateral sclerosis--an analysis based on cortical thickness.

    Science.gov (United States)

    Thorns, Johannes; Jansma, Henk; Peschel, Thomas; Grosskreutz, Julian; Mohammadi, Bahram; Dengler, Reinhard; Münte, Thomas F

    2013-10-18

    Besides the defining involvement of upper and lower motor neurons, the involvement of extramotor structures has been increasingly acknowledged in amyotrophic lateral sclerosis (ALS). Here we investigated a group of 14 mildly to moderately affected ALS patients and 14 age-matched healthy control participants using cortical thickness analysis. Cortical thickness was determined from high resolution 3D T1 magnetic resonance images and involved semiautomatic segmentation in grey and white matter, cortical alignment and determination of thickness using the Laplace method. In addition to a whole-cortex analysis a region of interest approach was applied. ALS patients showed regions of significant cortical thinning in the pre- and postcentral gyri bilaterally. Further regions of cortical thinning included superior and inferior parietal lobule, angular and supramarginal gyrus, insula, superior frontal, temporal and occipital regions, thus further substantiating extramotor involvement in ALS. A relationship between cortical thickness of the right superior frontal cortex and clinical severity (assessed by the ALS functional rating scale) was also demonstrated. Cortical thickness is reduced in ALS not only in motor areas but in widespread non-motor cortical areas. Cortical thickness is related to clinical severity.

  13. Cortico-cortical communication dynamics

    Directory of Open Access Journals (Sweden)

    Per E Roland

    2014-05-01

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

  14. Collagen and mineral deposition in rabbit cortical bone during maturation and growth: effects on tissue properties.

    Science.gov (United States)

    Isaksson, Hanna; Harjula, Terhi; Koistinen, Arto; Iivarinen, Jarkko; Seppänen, Kari; Arokoski, Jari P A; Brama, Pieter A; Jurvelin, Jukka S; Helminen, Heikki J

    2010-12-01

    We characterized the composition and mechanical properties of cortical bone during maturation and growth and in adult life in the rabbit. We hypothesized that the collagen network develops earlier than the mineralized matrix. Growth was monitored, and the rabbits were euthanized at birth (newborn), and at 1, 3, 6, 9, and 18 months of age. The collagen network was assessed biochemically (collagen content, enzymatic and non-enzymatic cross-links) in specimens from the mid-diaphysis of the tibia and femur and biomechanically (tensile testing) from decalcified whole tibia specimens. The mineralized matrix was analyzed using pQCT and 3-point bend tests from intact femur specimens. The collagen content and the Young's modulus of the collagen matrix increased significantly until the rabbits were 3 months old, and thereafter remained stable. The amount of HP and LP collagen cross-links increased continuously from newborn to 18 months of age, whereas PEN cross-links increased after 6 months of age. Bone mineral density and the Young's modulus of the mineralized bone increased until the rabbits were at least 6 months old. We concluded that substantial changes take place during the normal process of development in both the biochemical and biomechanical properties of rabbit cortical bone. In cortical bone, the collagen network reaches its mature composition and mechanical strength prior to the mineralized matrix. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  15. Comparing the influence of crestal cortical bone and sinus floor cortical bone in posterior maxilla bi-cortical dental implantation: a three-dimensional finite element analysis.

    Science.gov (United States)

    Yan, Xu; Zhang, Xinwen; Chi, Weichao; Ai, Hongjun; Wu, Lin

    2015-05-01

    This study aimed to compare the influence of alveolar ridge cortical bone and sinus floor cortical bone in sinus areabi-cortical dental implantation by means of 3D finite element analysis. Three-dimensional finite element (FE) models in a posterior maxillary region with sinus membrane and the same height of alveolar ridge of 10 mm were generated according to the anatomical data of the sinus area. They were either with fixed thickness of crestal cortical bone and variable thickness of sinus floor cortical bone or vice versa. Ten models were assumed to be under immediate loading or conventional loading. The standard implant model based on the Nobel Biocare implant system was created via computer-aided design software. All materials were assumed to be isotropic and linearly elastic. An inclined force of 129 N was applied. Von Mises stress mainly concentrated on the surface of crestal cortical bone around the implant neck. For all the models, both the axial and buccolingual resonance frequencies of conventional loading were higher than those of immediate loading; however, the difference is less than 5%. The results showed that bi-cortical implant in sinus area increased the stability of the implant, especially for immediately loading implantation. The thickness of both crestal cortical bone and sinus floor cortical bone influenced implant micromotion and stress distribution; however, crestal cortical bone may be more important than sinus floor cortical bone.

  16. Cortical representations of communication sounds.

    Science.gov (United States)

    Heiser, Marc A; Cheung, Steven W

    2008-10-01

    This review summarizes recent research into cortical processing of vocalizations in animals and humans. There has been a resurgent interest in this topic accompanied by an increased number of studies using animal models with complex vocalizations and new methods in human brain imaging. Recent results from such studies are discussed. Experiments have begun to reveal the bilateral cortical fields involved in communication sound processing and the transformations of neural representations that occur among those fields. Advances have also been made in understanding the neuronal basis of interaction between developmental exposures and behavioral experiences with vocalization perception. Exposure to sounds during the developmental period produces large effects on brain responses, as do a variety of specific trained tasks in adults. Studies have also uncovered a neural link between the motor production of vocalizations and the representation of vocalizations in cortex. Parallel experiments in humans and animals are answering important questions about vocalization processing in the central nervous system. This dual approach promises to reveal microscopic, mesoscopic, and macroscopic principles of large-scale dynamic interactions between brain regions that underlie the complex phenomenon of vocalization perception. Such advances will yield a greater understanding of the causes, consequences, and treatment of disorders related to speech processing.

  17. Polarization measurements through space-to-ground atmospheric propagation paths by using a highly polarized laser source in space.

    Science.gov (United States)

    Toyoshima, Morio; Takenaka, Hideki; Shoji, Yozo; Takayama, Yoshihisa; Koyama, Yoshisada; Kunimori, Hiroo

    2009-12-07

    The polarization characteristics of an artificial laser source in space were measured through space-to-ground atmospheric transmission paths. An existing Japanese laser communication satellite and optical ground station were used to measure Stokes parameters and the degree of polarization of the laser beam transmitted from the satellite. As a result, the polarization was preserved within an rms error of 1.6 degrees, and the degree of polarization was 99.4+/-4.4% through the space-to-ground atmosphere. These results contribute to the link estimation for quantum key distribution via space and provide the potential for enhancements in quantum cryptography worldwide in the future.

  18. Cortical microtubule nucleation can organise the cytoskeleton of Drosophila oocytes to define the anteroposterior axis

    Science.gov (United States)

    Khuc Trong, Philipp; Doerflinger, Hélène; Dunkel, Jörn; St Johnston, Daniel; Goldstein, Raymond E

    2015-01-01

    Many cells contain non-centrosomal arrays of microtubules (MTs), but the assembly, organisation and function of these arrays are poorly understood. We present the first theoretical model for the non-centrosomal MT cytoskeleton in Drosophila oocytes, in which bicoid and oskar mRNAs become localised to establish the anterior-posterior body axis. Constrained by experimental measurements, the model shows that a simple gradient of cortical MT nucleation is sufficient to reproduce the observed MT distribution, cytoplasmic flow patterns and localisation of oskar and naive bicoid mRNAs. Our simulations exclude a major role for cytoplasmic flows in localisation and reveal an organisation of the MT cytoskeleton that is more ordered than previously thought. Furthermore, modulating cortical MT nucleation induces a bifurcation in cytoskeletal organisation that accounts for the phenotypes of polarity mutants. Thus, our three-dimensional model explains many features of the MT network and highlights the importance of differential cortical MT nucleation for axis formation. DOI: http://dx.doi.org/10.7554/eLife.06088.001 PMID:26406117

  19. Wide-band polarization controller for Si photonic integrated circuits.

    Science.gov (United States)

    Velha, P; Sorianello, V; Preite, M V; De Angelis, G; Cassese, T; Bianchi, A; Testa, F; Romagnoli, M

    2016-12-15

    A circuit for the management of any arbitrary polarization state of light is demonstrated on an integrated silicon (Si) photonics platform. This circuit allows us to adapt any polarization into the standard fundamental TE mode of a Si waveguide and, conversely, to control the polarization and set it to any arbitrary polarization state. In addition, the integrated thermal tuning allows kilohertz speed which can be used to perform a polarization scrambler. The circuit was used in a WDM link and successfully used to adapt four channels into a standard Si photonic integrated circuit.

  20. Preliminary determination of calcium, phosphorus, and the calcium/phosphorus ratio in cortical bone of Chinstrap penguin using synchrotron X-ray fluorescence analysis

    Institute of Scientific and Technical Information of China (English)

    Xie Zhouqing; Cheng Bangbo; Sun Liguang; Huang Yuying; He Wei; Zhao Sanping

    2006-01-01

    Synchrotron radiation X-ray fluorescence (SR-XRF) approach was applied to analyzing of Chinstrap penguin (Pygoscelis Antarctica) cortical bone. The method enabled the in situ determination of Ca and P concentrations and the Ca/P ratio in cortical bone. The preliminary results show that: (1) there is the bone site-related difference for Ca and P concentrations. The mean values for the investigated parameters ( on a dry-weight basis) are: 30.7% (Ca) and 14.9% (P) for the femoral cortical bone, 21.4% (Ca) and 11.5% (P) for wing cortical bone. (2) The variation for the Ca/P ratio in cortical bone is lower than those for Ca and P separately.This is in agreement with the previous report that the specificity of the Ca/P ratio is better than that of Ca and P concentrations and is more reliable for the diagnosis of bone disorders. The authors suggest that further studies be conducted to establish normal values of Ca, P and Ca/P ratio for polar animals and provide a basis for the diagnosis of bone disorders.

  1. Rab3A, a possible marker of cortical granules, participates in cortical granule exocytosis in mouse eggs

    Energy Technology Data Exchange (ETDEWEB)

    Bello, Oscar Daniel; Cappa, Andrea Isabel; Paola, Matilde de; Zanetti, María Natalia [Instituto de Histología y Embriología, CONICET – Universidad Nacional de Cuyo, Av. Libertador 80, 5500 Mendoza (Argentina); Fukuda, Mitsunori [Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8578 (Japan); Fissore, Rafael A. [Department of Veterinary and Animal Sciences, University of Massachusetts Amherst, 661 North Pleasant Street, Amherst, MA 01003 (United States); Mayorga, Luis S. [Instituto de Histología y Embriología, CONICET – Universidad Nacional de Cuyo, Av. Libertador 80, 5500 Mendoza (Argentina); Michaut, Marcela A., E-mail: mmichaut@gmail.com [Instituto de Histología y Embriología, CONICET – Universidad Nacional de Cuyo, Av. Libertador 80, 5500 Mendoza (Argentina); Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo (Argentina)

    2016-09-10

    Fusion of cortical granules with the oocyte plasma membrane is the most significant event to prevent polyspermy. This particular exocytosis, also known as cortical reaction, is regulated by calcium and its molecular mechanism is still not known. Rab3A, a member of the small GTP-binding protein superfamily, has been implicated in calcium-dependent exocytosis and is not yet clear whether Rab3A participates in cortical granules exocytosis. Here, we examine the involvement of Rab3A in the physiology of cortical granules, particularly, in their distribution during oocyte maturation and activation, and their participation in membrane fusion during cortical granule exocytosis. Immunofluorescence and Western blot analysis showed that Rab3A and cortical granules have a similar migration pattern during oocyte maturation, and that Rab3A is no longer detected after cortical granule exocytosis. These results suggested that Rab3A might be a marker of cortical granules. Overexpression of EGFP-Rab3A colocalized with cortical granules with a Pearson correlation coefficient of +0.967, indicating that Rab3A and cortical granules have almost a perfect colocalization in the egg cortical region. Using a functional assay, we demonstrated that microinjection of recombinant, prenylated and active GST-Rab3A triggered cortical granule exocytosis, indicating that Rab3A has an active role in this secretory pathway. To confirm this active role, we inhibited the function of endogenous Rab3A by microinjecting a polyclonal antibody raised against Rab3A prior to parthenogenetic activation. Our results showed that Rab3A antibody microinjection abolished cortical granule exocytosis in parthenogenetically activated oocytes. Altogether, our findings confirm that Rab3A might function as a marker of cortical granules and participates in cortical granule exocytosis in mouse eggs. - Highlights: • Rab3A has a similar migration pattern to cortical granules in mouse oocytes. • Rab3A can be a marker of

  2. Demineralized Freeze-Dried Bovine Cortical Bone: Its Potential for Guided Bone Regeneration Membrane

    Directory of Open Access Journals (Sweden)

    David B. Kamadjaja

    2017-01-01

    Full Text Available Background. Bovine pericardium collagen membrane (BPCM had been widely used in guided bone regeneration (GBR whose manufacturing process usually required chemical cross-linking to prolong its biodegradation. However, cross-linking of collagen fibrils was associated with poorer tissue integration and delayed vascular invasion. Objective. This study evaluated the potential of bovine cortical bone collagen membrane for GBR by evaluating its antigenicity potential, cytotoxicity, immune and tissue response, and biodegradation behaviors. Material and Methods. Antigenicity potential of demineralized freeze-dried bovine cortical bone membrane (DFDBCBM was done with histology-based anticellularity evaluation, while cytotoxicity was analyzed using MTT Assay. Evaluation of immune response, tissue response, and biodegradation was done by randomly implanting DFDBCBM and BPCM in rat’s subcutaneous dorsum. Samples were collected at 2, 5, and 7 days and 7, 14, 21, and 28 days for biocompatibility and tissue response-biodegradation study, respectively. Result. DFDBCBM, histologically, showed no retained cells; however, it showed some level of in vitro cytotoxicity. In vivo study exhibited increased immune response to DFDBCBM in early healing phase; however, normal tissue response and degradation rate were observed up to 4 weeks after DFDBCBM implantation. Conclusion. Demineralized freeze-dried bovine cortical bone membrane showed potential for clinical application; however, it needs to be optimized in its biocompatibility to fulfill all requirements for GBR membrane.

  3. Cortical Visual Impairment

    Science.gov (United States)

    ... resolves by one year of life. Is “cortical blindness” the same thing as CVI? Cortical blindness is ... What visual characteristics are associated with CVI? • Distinct color preferences • Variable level of vision loss, often demonstrating ...

  4. Qualia could arise from information processing in local cortical networks.

    Science.gov (United States)

    Orpwood, Roger

    2013-01-01

    Re-entrant feedback, either within sensory cortex or arising from prefrontal areas, has been strongly linked to the emergence of consciousness, both in theoretical and experimental work. This idea, together with evidence for local micro-consciousness, suggests the generation of qualia could in some way result from local network activity under re-entrant activation. This paper explores the possibility by examining the processing of information by local cortical networks. It highlights the difference between the information structure (how the information is physically embodied), and the information message (what the information is about). It focuses on the network's ability to recognize information structures amongst its inputs under conditions of extensive local feedback, and to then assign information messages to those structures. It is shown that if the re-entrant feedback enables the network to achieve an attractor state, then the message assigned in any given pass of information through the network is a representation of the message assigned in the previous pass-through of information. Based on this ability the paper argues that as information is repeatedly cycled through the network, the information message that is assigned evolves from a recognition of what the input structure is, to what it is like, to how it appears, to how it seems. It could enable individual networks to be the site of qualia generation. The paper goes on to show networks in cortical layers 2/3 and 5a have the connectivity required for the behavior proposed, and reviews some evidence for a link between such local cortical cyclic activity and conscious percepts. It concludes with some predictions based on the theory discussed.

  5. Aging causes a reorganization of cortical and spinal control of posture

    Directory of Open Access Journals (Sweden)

    Selma ePapegaaij

    2014-03-01

    Full Text Available Classical studies in animal preparations suggest a strong role for spinal control of posture. In young adults it is now established that the cerebral cortex contributes to postural control of unperturbed and perturbed standing. The age-related degeneration and accompanying functional changes in the brain, reported so far mainly in conjunction with simple manual motor tasks, may also affect the mechanisms that control complex motor tasks involving posture. This review outlines the age-related structural and functional changes at spinal and cortical levels and provides a mechanistic analysis of how such changes may be linked to the behaviorally manifest postural deficits in old adults. The emerging picture is that the age-related reorganization in motor control during voluntary tasks, characterized by differential modulation of spinal reflexes, greater cortical activation and cortical disinhibition, is also present during postural tasks. We discuss the possibility that this reorganization underlies the increased coactivation and dual task interference reported in elderly. Finally, we propose a model for future studies to unravel the structure-function-behavior relations in postural control and aging.

  6. Complement is activated in progressive multiple sclerosis cortical grey matter lesions.

    Science.gov (United States)

    Watkins, Lewis M; Neal, James W; Loveless, Sam; Michailidou, Iliana; Ramaglia, Valeria; Rees, Mark I; Reynolds, Richard; Robertson, Neil P; Morgan, B Paul; Howell, Owain W

    2016-06-22

    The symptoms of multiple sclerosis (MS) are caused by damage to myelin and nerve cells in the brain and spinal cord. Inflammation is tightly linked with neurodegeneration, and it is the accumulation of neurodegeneration that underlies increasing neurological disability in progressive MS. Determining pathological mechanisms at play in MS grey matter is therefore a key to our understanding of disease progression. We analysed complement expression and activation by immunocytochemistry and in situ hybridisation in frozen or formalin-fixed paraffin-embedded post-mortem tissue blocks from 22 progressive MS cases and made comparisons to inflammatory central nervous system disease and non-neurological disease controls. Expression of the transcript for C1qA was noted in neurons and the activation fragment and opsonin C3b-labelled neurons and glia in the MS cortical and deep grey matter. The density of immunostained cells positive for the classical complement pathway protein C1q and the alternative complement pathway activation fragment Bb was significantly increased in cortical grey matter lesions in comparison to control grey matter. The number of cells immunostained for the membrane attack complex was elevated in cortical lesions, indicating complement activation to completion. The numbers of classical (C1-inhibitor) and alternative (factor H) pathway regulator-positive cells were unchanged between MS and controls, whilst complement anaphylatoxin receptor-bearing microglia in the MS cortex were found closely apposed to cortical neurons. Complement immunopositive neurons displayed an altered nuclear morphology, indicative of cell stress/damage, supporting our finding of significant neurodegeneration in cortical grey matter lesions. Complement is activated in the MS cortical grey matter lesions in areas of elevated numbers of complement receptor-positive microglia and suggests that complement over-activation may contribute to the worsening pathology that underlies the

  7. Impaired hair follicle morphogenesis and polarized keratinocyte movement upon conditional inactivation of integrin-linked kinase in the epidermis.

    Science.gov (United States)

    Nakrieko, Kerry-Ann; Welch, Ian; Dupuis, Holly; Bryce, Dawn; Pajak, Agnieszka; St Arnaud, René; Dedhar, Shoukat; D'Souza, Sudhir J A; Dagnino, Lina

    2008-04-01

    Integrin-linked kinase (ILK) is key for cell survival, migration, and adhesion, but little is known about its role in epidermal development and homeostasis in vivo. We generated mice with conditional inactivation of the Ilk gene in squamous epithelia. These mice die perinatally and exhibit skin blistering and severe defects in hair follicle morphogenesis, including greatly reduced follicle numbers, failure to progress beyond very early developmental stages, and pronounced defects in follicular keratinocyte proliferation. ILK-deficient epidermis shows abnormalities in adhesion to the basement membrane and in differentiation. ILK-deficient cultured keratinocytes fail to attach and spread efficiently and exhibit multiple abnormalities in actin cytoskeletal organization. Ilk gene inactivation in cultured keratinocytes causes impaired ability to form stable lamellipodia, to directionally migrate, and to polarize. These defects are accompanied by abnormal distribution of active Cdc42 to cell protrusions, as well as reduced activation of Rac1 upon induction of cell migration in scraped keratinocyte monolayers. Significantly, alterations in cell spreading and forward movement in single cells can be rescued by expression of constitutively active Rac1 or RhoG. Our studies underscore a central and distinct role for ILK in hair follicle development and in polarized cell movements, two key aspects of epithelial morphogenesis and function.

  8. SLEEP AND OLFACTORY CORTICAL PLASTICITY

    Directory of Open Access Journals (Sweden)

    Dylan eBarnes

    2014-04-01

    Full Text Available In many systems, sleep plays a vital role in memory consolidation and synaptic homeostasis. These processes together help store information of biological significance and reset synaptic circuits to facilitate acquisition of information in the future. In this review, we describe recent evidence of sleep-dependent changes in olfactory system structure and function which contribute to odor memory and perception. During slow-wave sleep, the piriform cortex becomes hypo-responsive to odor stimulation and instead displays sharp-wave activity similar to that observed within the hippocampal formation. Furthermore, the functional connectivity between the piriform cortex and other cortical and limbic regions is enhanced during slow-wave sleep compared to waking. This combination of conditions may allow odor memory consolidation to occur during a state of reduced external interference and facilitate association of odor memories with stored hedonic and contextual cues. Evidence consistent with sleep-dependent odor replay within olfactory cortical circuits is presented. These data suggest that both the strength and precision of odor memories is sleep-dependent. The work further emphasizes the critical role of synaptic plasticity and memory in not only odor memory but also basic odor perception. The work also suggests a possible link between sleep disturbances that are frequently co-morbid with a wide range of pathologies including Alzheimer’s disease, schizophrenia and depression and the known olfactory impairments associated with those disorders.

  9. Rotational inertia of continents: A proposed link between polar wandering and plate tectonics

    Science.gov (United States)

    Kane, M.F.

    1972-01-01

    A mechanism is proposed whereby displacement between continents and the earth's pole of rotation (polar wandering) gives rise to latitudinal transport of continental plates (continental drift) because of their relatively greater rotational inertia. When extended to short-term polar wobble, the hypothesis predicts an energy change nearly equivalent to the seismic energy rate.

  10. Visual and Motor Recovery After "Cognitive Therapeutic Exercises" in Cortical Blindness: A Case Study.

    Science.gov (United States)

    De Patre, Daniele; Van de Winckel, Ann; Panté, Franca; Rizzello, Carla; Zernitz, Marina; Mansour, Mariam; Zordan, Lara; Zeffiro, Thomas A; OʼConnor, Erin E; Bisson, Teresa; Lupi, Andrea; Perfetti, Carlo

    2017-07-01

    Spontaneous visual recovery is rare after cortical blindness. While visual rehabilitation may improve performance, no visual therapy has been widely adopted, as clinical outcomes are variable and rarely translate into improvements in activities of daily living (ADLs). We explored the potential value of a novel rehabilitation approach "cognitive therapeutic exercises" for cortical blindness. The subject of this case study was 48-year-old woman with cortical blindness and tetraplegia after cardiac arrest. Prior to the intervention, she was dependent in ADLs and poorly distinguished shapes and colors after 19 months of standard visual and motor rehabilitation. Computed tomographic images soon after symptom onset demonstrated acute infarcts in both occipital cortices. The subject underwent 8 months of intensive rehabilitation with "cognitive therapeutic exercises" consisting of discrimination exercises correlating sensory and visual information. Visual fields increased; object recognition improved; it became possible to watch television; voluntary arm movements improved in accuracy and smoothness; walking improved; and ADL independence and self-reliance increased. Subtraction of neuroimaging acquired before and after rehabilitation showed that focal glucose metabolism increases bilaterally in the occipital poles. This study demonstrates feasibility of "cognitive therapeutic exercises" in an individual with cortical blindness, who experienced impressive visual and sensorimotor recovery, with marked ADL improvement, more than 2 years after ischemic cortical damage.Video Abstract available for additional insights from the authors (see Video, Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A173).

  11. Motor activation in SPG4-linked hereditary spastic paraplegia

    DEFF Research Database (Denmark)

    Scheuer, KH; Nielsen, JE; Krabbe, Katja

    2006-01-01

    OBJECTIVE: The aim of this study was to investigate the extent of motor cortical functional reorganisation in patients with SPG4-linked hereditary spastic paraplegia by exploring cortical motor activation related to movements of clinically affected (lower) and unaffected (upper) limbs. METHODS......: Thirteen patients and 13 normal controls matched for age, gender and handedness underwent O15-labelled water positron emission tomography during (1) right ankle flexion-extension, (2) right shoulder flexion-extension and (3) rest. Within-group comparisons of movement vs. rest (simple main effects......, the supplementary motor areas and the right premotor cortex compared to controls. CONCLUSIONS: Motor cortical reorganisation may explain this result, but as no significant differences were recognised in the motor response of the unaffected limb, differences in functional demands should also be considered...

  12. Assessment of cortical maturation with prenatal MRI. Part I: normal cortical maturation

    Energy Technology Data Exchange (ETDEWEB)

    Fogliarini, Celine [Faculte Timone, Centre de Resonance Magnetique Biologique et Medicale, Marseille (France); Chaumoitre, Katia [Hopital Nord, Department of Radiology, Marseille (France); Chapon, Frederique; Levrier, Olivier; Girard, Nadine [Hopital Timone, Department of Neuroradiology, Marseille Cedex 5 (France); Fernandez, Carla; Figarella-Branger, Dominique [Hopital Timone, Department of Pathology, Marseille (France)

    2005-08-01

    Cortical maturation, especially gyral formation, follows a temporospatial schedule and is a good marker of fetal maturation. Although ultrasonography is still the imaging method of choice to evaluate fetal anatomy, MRI has an increasingly important role in the detection of brain abnormalities, especially of cortical development. Knowledge of MRI techniques in utero with the advantages and disadvantages of some sequences is necessary, in order to try to optimize the different magnetic resonance sequences to be able to make an early diagnosis. The different steps of cortical maturation known from histology represent the background necessary for the understanding of maturation in order to be then able to evaluate brain maturation through neuroimaging. Illustrations of the normal cortical maturation are given for each step accessible to MRI for both the cerebral hemispheres and the posterior fossa. (orig.)

  13. Assessment of cortical maturation with prenatal MRI. Part I: normal cortical maturation

    International Nuclear Information System (INIS)

    Fogliarini, Celine; Chaumoitre, Katia; Chapon, Frederique; Levrier, Olivier; Girard, Nadine; Fernandez, Carla; Figarella-Branger, Dominique

    2005-01-01

    Cortical maturation, especially gyral formation, follows a temporospatial schedule and is a good marker of fetal maturation. Although ultrasonography is still the imaging method of choice to evaluate fetal anatomy, MRI has an increasingly important role in the detection of brain abnormalities, especially of cortical development. Knowledge of MRI techniques in utero with the advantages and disadvantages of some sequences is necessary, in order to try to optimize the different magnetic resonance sequences to be able to make an early diagnosis. The different steps of cortical maturation known from histology represent the background necessary for the understanding of maturation in order to be then able to evaluate brain maturation through neuroimaging. Illustrations of the normal cortical maturation are given for each step accessible to MRI for both the cerebral hemispheres and the posterior fossa. (orig.)

  14. The cortical signature of amyotrophic lateral sclerosis.

    Directory of Open Access Journals (Sweden)

    Federica Agosta

    Full Text Available The aim of this study was to explore the pattern of regional cortical thickness in patients with non-familial amyotrophic lateral sclerosis (ALS and to investigate whether cortical thinning is associated with disease progression rate. Cortical thickness analysis was performed in 44 ALS patients and 26 healthy controls. Group differences in cortical thickness and the age-by-group effects were assessed using vertex-by-vertex and multivariate linear models. The discriminatory ability of MRI variables in distinguishing patients from controls was estimated using the Concordance Statistics (C-statistic within logistic regression analyses. Correlations between cortical thickness measures and disease progression rate were tested using the Pearson coefficient. Relative to controls, ALS patients showed a bilateral cortical thinning of the primary motor, prefrontal and ventral frontal cortices, cingulate gyrus, insula, superior and inferior temporal and parietal regions, and medial and lateral occipital areas. There was a significant age-by-group effect in the sensorimotor cortices bilaterally, suggesting a stronger association between age and cortical thinning in ALS patients compared to controls. The mean cortical thickness of the sensorimotor cortices distinguished patients with ALS from controls (C-statistic ≥ 0.74. Cortical thinning of the left sensorimotor cortices was related to a faster clinical progression (r = -0.33, p = 0.03. Cortical thickness measurements allowed the detection and quantification of motor and extramotor involvement in patients with ALS. Cortical thinning of the precentral gyrus might offer a marker of upper motor neuron involvement and disease progression.

  15. The cortical signature of amyotrophic lateral sclerosis.

    Science.gov (United States)

    Agosta, Federica; Valsasina, Paola; Riva, Nilo; Copetti, Massimiliano; Messina, Maria Josè; Prelle, Alessandro; Comi, Giancarlo; Filippi, Massimo

    2012-01-01

    The aim of this study was to explore the pattern of regional cortical thickness in patients with non-familial amyotrophic lateral sclerosis (ALS) and to investigate whether cortical thinning is associated with disease progression rate. Cortical thickness analysis was performed in 44 ALS patients and 26 healthy controls. Group differences in cortical thickness and the age-by-group effects were assessed using vertex-by-vertex and multivariate linear models. The discriminatory ability of MRI variables in distinguishing patients from controls was estimated using the Concordance Statistics (C-statistic) within logistic regression analyses. Correlations between cortical thickness measures and disease progression rate were tested using the Pearson coefficient. Relative to controls, ALS patients showed a bilateral cortical thinning of the primary motor, prefrontal and ventral frontal cortices, cingulate gyrus, insula, superior and inferior temporal and parietal regions, and medial and lateral occipital areas. There was a significant age-by-group effect in the sensorimotor cortices bilaterally, suggesting a stronger association between age and cortical thinning in ALS patients compared to controls. The mean cortical thickness of the sensorimotor cortices distinguished patients with ALS from controls (C-statistic ≥ 0.74). Cortical thinning of the left sensorimotor cortices was related to a faster clinical progression (r = -0.33, p = 0.03). Cortical thickness measurements allowed the detection and quantification of motor and extramotor involvement in patients with ALS. Cortical thinning of the precentral gyrus might offer a marker of upper motor neuron involvement and disease progression.

  16. Cortical bone metastases

    International Nuclear Information System (INIS)

    Davis, T.M. Jr.; Rogers, L.F.; Hendrix, R.W.

    1986-01-01

    Twenty-five cases of bone metastases involving the cortex alone are reviewed. Seven patients had primary lung carcinoma, while 18 had primary tumors not previously reported to produce cortical bone metastases (tumors of the breast, kidney, pancreas, adenocarcinoma of unknown origin, multiple myeloma). Radiographically, these cortical lesions were well circumscribed, osteolytic, and produced soft-tissue swelling and occasional periosteal reaction. A recurrent pattern of metadiaphyseal involvement of the long bones of the lower extremity (particularly the femur) was noted, and is discussed. Findings reported in the literature, review, pathophysiology, and the role of skeletal radiographs, bone scans, and CT scans in evaluating cortical bone metastases are addressed

  17. Alterations in Normal Aging Revealed by Cortical Brain Network Constructed Using IBASPM.

    Science.gov (United States)

    Li, Wan; Yang, Chunlan; Shi, Feng; Wang, Qun; Wu, Shuicai; Lu, Wangsheng; Li, Shaowu; Nie, Yingnan; Zhang, Xin

    2018-04-16

    Normal aging has been linked with the decline of cognitive functions, such as memory and executive skills. One of the prominent approaches to investigate the age-related alterations in the brain is by examining the cortical brain connectome. IBASPM is a toolkit to realize individual atlas-based volume measurement. Hence, this study seeks to determine what further alterations can be revealed by cortical brain networks formed by IBASPM-extracted regional gray matter volumes. We found the reduced strength of connections between the superior temporal pole and middle temporal pole in the right hemisphere, global hubs as the left fusiform gyrus and right Rolandic operculum in the young and aging groups, respectively, and significantly reduced inter-module connection of one module in the aging group. These new findings are consistent with the phenomenon of normal aging mentioned in previous studies and suggest that brain network built with the IBASPM could provide supplementary information to some extent. The individualization of morphometric features extraction deserved to be given more attention in future cortical brain network research.

  18. Electrically polarized PLLA nanofibers as neural tissue engineering scaffolds with improved neuritogenesis.

    Science.gov (United States)

    Barroca, Nathalie; Marote, Ana; Vieira, Sandra I; Almeida, Abílio; Fernandes, Maria H V; Vilarinho, Paula M; da Cruz E Silva, Odete A B

    2018-07-01

    Tissue engineering is evolving towards the production of smart platforms exhibiting stimulatory cues to guide tissue regeneration. This work explores the benefits of electrical polarization to produce more efficient neural tissue engineering platforms. Poly (l-lactic) acid (PLLA)-based scaffolds were prepared as solvent cast films and electrospun aligned nanofibers, and electrically polarized by an in-lab built corona poling device. The characterization of the platforms by thermally stimulated depolarization currents reveals a polarization of 60 × 10 -10 C cm -2 that is stable on poled electrospun nanofibers for up to 6 months. Further in vitro studies using neuroblastoma cells reveals that platforms' polarization potentiates Retinoic Acid-induced neuronal differentiation. Additionally, in differentiating embryonic cortical neurons, poled aligned nanofibers further increased neurite outgrowth by 30% (+70 μm) over non-poled aligned nanofibers, and by 50% (+100 μm) over control conditions. Therefore, the synergy of topographical cues and electrical polarization of poled aligned nanofibers places them as promising biocompatible and bioactive platforms for neural tissue regeneration. Given their long lasting induced polarization, these PLLA poled nanofibrous scaffolds can be envisaged as therapeutic devices of long shelf life for neural repair applications. Copyright © 2018 Elsevier B.V. All rights reserved.

  19. Mapping human brain networks with cortico-cortical evoked potentials

    Science.gov (United States)

    Keller, Corey J.; Honey, Christopher J.; Mégevand, Pierre; Entz, Laszlo; Ulbert, Istvan; Mehta, Ashesh D.

    2014-01-01

    The cerebral cortex forms a sheet of neurons organized into a network of interconnected modules that is highly expanded in humans and presumably enables our most refined sensory and cognitive abilities. The links of this network form a fundamental aspect of its organization, and a great deal of research is focusing on understanding how information flows within and between different regions. However, an often-overlooked element of this connectivity regards a causal, hierarchical structure of regions, whereby certain nodes of the cortical network may exert greater influence over the others. While this is difficult to ascertain non-invasively, patients undergoing invasive electrode monitoring for epilepsy provide a unique window into this aspect of cortical organization. In this review, we highlight the potential for cortico-cortical evoked potential (CCEP) mapping to directly measure neuronal propagation across large-scale brain networks with spatio-temporal resolution that is superior to traditional neuroimaging methods. We first introduce effective connectivity and discuss the mechanisms underlying CCEP generation. Next, we highlight how CCEP mapping has begun to provide insight into the neural basis of non-invasive imaging signals. Finally, we present a novel approach to perturbing and measuring brain network function during cognitive processing. The direct measurement of CCEPs in response to electrical stimulation represents a potentially powerful clinical and basic science tool for probing the large-scale networks of the human cerebral cortex. PMID:25180306

  20. Central-moment description of polarization for quantum states of light

    DEFF Research Database (Denmark)

    Björk, G.; Söderholm, J.; Kim, Y.-S.

    2012-01-01

    We present a moment expansion for the systematic characterization of the polarization properties of quantum states of light. Specifically,we link the method to themeasurements of the Stokes operator in different directions on the Poincar´e sphere and provide a scheme for polarization tomography w...

  1. Intrinsic Connections of the Core Auditory Cortical Regions and Rostral Supratemporal Plane in the Macaque Monkey.

    Science.gov (United States)

    Scott, Brian H; Leccese, Paul A; Saleem, Kadharbatcha S; Kikuchi, Yukiko; Mullarkey, Matthew P; Fukushima, Makoto; Mishkin, Mortimer; Saunders, Richard C

    2017-01-01

    In the ventral stream of the primate auditory cortex, cortico-cortical projections emanate from the primary auditory cortex (AI) along 2 principal axes: one mediolateral, the other caudorostral. Connections in the mediolateral direction from core, to belt, to parabelt, have been well described, but less is known about the flow of information along the supratemporal plane (STP) in the caudorostral dimension. Neuroanatomical tracers were injected throughout the caudorostral extent of the auditory core and rostral STP by direct visualization of the cortical surface. Auditory cortical areas were distinguished by SMI-32 immunostaining for neurofilament, in addition to established cytoarchitectonic criteria. The results describe a pathway comprising step-wise projections from AI through the rostral and rostrotemporal fields of the core (R and RT), continuing to the recently identified rostrotemporal polar field (RTp) and the dorsal temporal pole. Each area was strongly and reciprocally connected with the areas immediately caudal and rostral to it, though deviations from strictly serial connectivity were observed. In RTp, inputs converged from core, belt, parabelt, and the auditory thalamus, as well as higher order cortical regions. The results support a rostrally directed flow of auditory information with complex and recurrent connections, similar to the ventral stream of macaque visual cortex. Published by Oxford University Press 2015. This work is written by (a) US Government employee(s) and is in the public domain in the US.

  2. Motivated malleability: Frontal cortical asymmetry predicts the susceptibility to social influence.

    Science.gov (United States)

    Schnuerch, Robert; Pfattheicher, Stefan

    2017-07-16

    Humans, just as many other animals, regulate their behavior in terms of approaching stimuli associated with pleasure and avoiding stimuli linked to harm. A person's current and chronic motivational direction - that is, approach versus avoidance orientation - is reliably reflected in the asymmetry of frontal cortical low-frequency oscillations. Using resting electroencephalography (EEG), we show that frontal asymmetry is predictive of the tendency to yield to social influence: Stronger right- than left-side frontolateral activation during a resting-state session prior to the experiment was robustly associated with a stronger inclination to adopt a peer group's judgments during perceptual decision-making (Study 1). We posit that this reflects the role of a person's chronic avoidance orientation in socially adjusted behavior. This claim was strongly supported by additional survey investigations (Studies 2a, 2b, 2c), all of which consistently revealed that trait avoidance was positively linked to the susceptibility to social influence. The present contribution thus stresses the relevance of chronic avoidance orientation in social conformity, refining (yet not contradicting) the longstanding view that socially influenced behavior is motivated by approach-related goals. Moreover, our findings valuably underscore and extend our knowledge on the association between frontal cortical asymmetry and a variety of psychological variables.

  3. Censoring distances based on labeled cortical distance maps in cortical morphometry.

    Science.gov (United States)

    Ceyhan, Elvan; Nishino, Tomoyuki; Alexopolous, Dimitrios; Todd, Richard D; Botteron, Kelly N; Miller, Michael I; Ratnanather, J Tilak

    2013-01-01

    It has been demonstrated that shape differences in cortical structures may be manifested in neuropsychiatric disorders. Such morphometric differences can be measured by labeled cortical distance mapping (LCDM) which characterizes the morphometry of the laminar cortical mantle of cortical structures. LCDM data consist of signed/labeled distances of gray matter (GM) voxels with respect to GM/white matter (WM) surface. Volumes and other summary measures for each subject and the pooled distances can help determine the morphometric differences between diagnostic groups, however they do not reveal all the morphometric information contained in LCDM distances. To extract more information from LCDM data, censoring of the pooled distances is introduced for each diagnostic group where the range of LCDM distances is partitioned at a fixed increment size; and at each censoring step, the distances not exceeding the censoring distance are kept. Censored LCDM distances inherit the advantages of the pooled distances but also provide information about the location of morphometric differences which cannot be obtained from the pooled distances. However, at each step, the censored distances aggregate, which might confound the results. The influence of data aggregation is investigated with an extensive Monte Carlo simulation analysis and it is demonstrated that this influence is negligible. As an illustrative example, GM of ventral medial prefrontal cortices (VMPFCs) of subjects with major depressive disorder (MDD), subjects at high risk (HR) of MDD, and healthy control (Ctrl) subjects are used. A significant reduction in laminar thickness of the VMPFC in MDD and HR subjects is observed compared to Ctrl subjects. Moreover, the GM LCDM distances (i.e., locations with respect to the GM/WM surface) for which these differences start to occur are determined. The methodology is also applicable to LCDM-based morphometric measures of other cortical structures affected by disease.

  4. Censoring Distances Based on Labeled Cortical Distance Maps in Cortical Morphometry

    Directory of Open Access Journals (Sweden)

    Elvan eCeyhan

    2013-10-01

    Full Text Available It has been demonstrated that shape differences are manifested in cortical structures due to neuropsychiatric disorders. Such morphometric differences can be measured by labeled cortical distance mapping (LCDM which characterizes the morphometry of the laminar cortical mantle of cortical structures. LCDM data consist of signed/labeled distances of gray matter (GM voxels with respect to GM/white matter (WM surface. Volumes and other summary measures for each subject and the pooled distances can help determine the morphometric differences between diagnostic groups, however they do not reveal all the morphometric information con-tained in LCDM distances. To extract more information from LCDM data, censoring of the pooled distances is introduced for each diagnostic group where the range of LCDM distances is partitioned at a fixed increment size; and at each censoring step, the distances not exceeding the censoring distance are kept. Censored LCDM distances inherit the advantages of the pooled distances but also provide information about the location of morphometric differences which cannot be obtained from the pooled distances. However, at each step, the censored distances aggregate, which might confound the results. The influence of data aggregation is investigated with an extensive Monte Carlo simulation analysis and it is demonstrated that this influence is negligible. As an illustrative example, GM of ventral medial prefrontal cortices (VMPFCs of subjects with major depressive disorder (MDD, subjects at high risk (HR of MDD, and healthy control (Ctrl subjects are used. A significant reduction in laminar thickness of the VMPFC in MDD and HR subjects is observed compared to Ctrl subjects. Moreover, the GM LCDM distances (i.e., locations with respect to the GM/WM surface for which these differences start to occur are determined. The methodology is also applicable to LCDM-based morphometric measures of other cortical structures affected by disease.

  5. Assessment of cortical and sub-cortical function in neonates by electrophysiological monitoring

    NARCIS (Netherlands)

    Jennekens, W.

    2012-01-01

    The aim of this thesis was the assessment of cortical and sub-cortical function in neonates by electrophysiological monitoring, i.e. to evaluate the function of the neonatal cortex and brainstem through quantitative analysis of signals readily available in the NICU. These signals include

  6. Music listening engages specific cortical regions within the temporal lobes: differences between musicians and non-musicians.

    Science.gov (United States)

    Angulo-Perkins, Arafat; Aubé, William; Peretz, Isabelle; Barrios, Fernando A; Armony, Jorge L; Concha, Luis

    2014-10-01

    Music and speech are two of the most relevant and common sounds in the human environment. Perceiving and processing these two complex acoustical signals rely on a hierarchical functional network distributed throughout several brain regions within and beyond the auditory cortices. Given their similarities, the neural bases for processing these two complex sounds overlap to a certain degree, but particular brain regions may show selectivity for one or the other acoustic category, which we aimed to identify. We examined 53 subjects (28 of them professional musicians) by functional magnetic resonance imaging (fMRI), using a paradigm designed to identify regions showing increased activity in response to different types of musical stimuli, compared to different types of complex sounds, such as speech and non-linguistic vocalizations. We found a region in the anterior portion of the superior temporal gyrus (aSTG) (planum polare) that showed preferential activity in response to musical stimuli and was present in all our subjects, regardless of musical training, and invariant across different musical instruments (violin, piano or synthetic piano). Our data show that this cortical region is preferentially involved in processing musical, as compared to other complex sounds, suggesting a functional role as a second-order relay, possibly integrating acoustic characteristics intrinsic to music (e.g., melody extraction). Moreover, we assessed whether musical experience modulates the response of cortical regions involved in music processing and found evidence of functional differences between musicians and non-musicians during music listening. In particular, bilateral activation of the planum polare was more prevalent, but not exclusive, in musicians than non-musicians, and activation of the right posterior portion of the superior temporal gyrus (planum temporale) differed between groups. Our results provide evidence of functional specialization for music processing in specific

  7. Regulator of G protein signaling 5 (RGS5) inhibits sonic hedgehog function in mouse cortical neurons.

    Science.gov (United States)

    Liu, Chuanliang; Hu, Qiongqiong; Jing, Jia; Zhang, Yun; Jin, Jing; Zhang, Liulei; Mu, Lili; Liu, Yumei; Sun, Bo; Zhang, Tongshuai; Kong, Qingfei; Wang, Guangyou; Wang, Dandan; Zhang, Yao; Liu, Xijun; Zhao, Wei; Wang, Jinghua; Feng, Tao; Li, Hulun

    2017-09-01

    Regulator of G protein signaling 5 (RGS5) acts as a GTPase-activating protein (GAP) for the Gαi subunit and negatively regulates G protein-coupled receptor signaling. However, its presence and function in postmitotic differentiated primary neurons remains largely uncharacterized. During neural development, sonic hedgehog (Shh) signaling is involved in cell signaling pathways via Gαi activity. In particular, Shh signaling is essential for embryonic neural tube patterning, which has been implicated in neuronal polarization involving neurite outgrowth. Here, we examined whether RGS5 regulates Shh signaling in neurons. RGS5 transcripts were found to be expressed in cortical neurons and their expression gradually declined in a time-dependent manner in culture system. When an adenovirus expressing RGS5 was introduced into an in vitro cell culture model of cortical neurons, RGS5 overexpression significantly reduced neurite outgrowth and FM4-64 uptake, while cAMP-PKA signaling was also affected. These findings suggest that RGS5 inhibits Shh function during neurite outgrowth and the presynaptic terminals of primary cortical neurons mature via modulation of cAMP. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Frontal cortical control of posterior sensory and association cortices through the claustrum.

    Science.gov (United States)

    White, Michael G; Mathur, Brian N

    2018-04-06

    The claustrum is a telencephalic gray matter nucleus that is richly interconnected with the neocortex. This structure subserves top-down executive functions that require frontal cortical control of posterior cortical regions. However, functional anatomical support for the claustrum allowing for long-range intercortical communication is lacking. To test this, we performed a channelrhodopsin-assisted long-circuit mapping strategy in mouse brain slices. We find that anterior cingulate cortex input to the claustrum is transiently amplified by claustrum neurons that, in turn, project to parietal association cortex or to primary and secondary visual cortices. Additionally, we observe that claustrum drive of cortical neurons in parietal association cortex is layer-specific, eliciting action potential generation briefly in layers II/III, IV, and VI but not V. These data are the first to provide a functional anatomical substrate through claustrum that may underlie top-down functions, such as executive attention or working memory, providing critical insight to this most interconnected and enigmatic nucleus.

  9. Critical fluctuations in cortical models near instability

    Directory of Open Access Journals (Sweden)

    Matthew J. Aburn

    2012-08-01

    Full Text Available Computational studies often proceed from the premise that cortical dynamics operate in a linearly stable domain, where fluctuations dissipate quickly and show only short memory. Studies of human EEG, however, have shown significant autocorrelation at time lags on the scale of minutes, indicating the need to consider regimes where nonlinearities influence the dynamics. Statistical properties such as increased autocorrelation length, increased variance, power-law scaling and bistable switching have been suggested as generic indicators of the approach to bifurcation in nonlinear dynamical systems. We study temporal fluctuations in a widely-employed computational model (the Jansen-Rit model of cortical activity, examining the statistical signatures that accompany bifurcations. Approaching supercritical Hopf bifurcations through tuning of the background excitatory input, we find a dramatic increase in the autocorrelation length that depends sensitively on the direction in phase space of the input fluctuations and hence on which neuronal subpopulation is stochastically perturbed. Similar dependence on the input direction is found in the distribution of fluctuation size and duration, which show power law scaling that extends over four orders of magnitude at the Hopf bifurcation. We conjecture that the alignment in phase space between the input noise vector and the center manifold of the Hopf bifurcation is directly linked to these changes. These results are consistent with the possibility of statistical indicators of linear instability being detectable in real EEG time series. However, even in a simple cortical model, we find that these indicators may not necessarily be visible even when bifurcations are present because their expression can depend sensitively on the neuronal pathway of incoming fluctuations.

  10. Trade-off of cerebello-cortical and cortico-cortical functional networks for planning in 6-year-old children.

    Science.gov (United States)

    Kipping, Judy A; Margulies, Daniel S; Eickhoff, Simon B; Lee, Annie; Qiu, Anqi

    2018-05-03

    Childhood is a critical period for the development of cognitive planning. There is a lack of knowledge on its neural mechanisms in children. This study aimed to examine cerebello-cortical and cortico-cortical functional connectivity in association with planning skills in 6-year-olds (n = 76). We identified the cerebello-cortical and cortico-cortical functional networks related to cognitive planning using activation likelihood estimation (ALE) meta-analysis on existing functional imaging studies on spatial planning, and data-driven independent component analysis (ICA) of children's resting-state functional MRI (rs-fMRI). We investigated associations of cerebello-cortical and cortico-cortical functional connectivity with planning ability in 6-year-olds, as assessed using the Stockings of Cambridge task. Long-range functional connectivity of two cerebellar networks (lobules VI and lateral VIIa) with the prefrontal and premotor cortex were greater in children with poorer planning ability. In contrast, cortico-cortical association networks were not associated with the performance of planning in children. These results highlighted the key contribution of the lateral cerebello-frontal functional connectivity, but not cortico-cortical association functional connectivity, for planning ability in 6-year-olds. Our results suggested that brain adaptation to the acquisition of planning ability during childhood is partially achieved through the engagement of the cerebello-cortical functional connectivity. Copyright © 2018 Elsevier Inc. All rights reserved.

  11. Microtubule dynamics of the centrosome-like polar organizers from the basal land plant Marchantia polymorpha.

    Science.gov (United States)

    Buschmann, Henrik; Holtmannspötter, Michael; Borchers, Agnes; O'Donoghue, Martin-Timothy; Zachgo, Sabine

    2016-02-01

    The liverwort Marchantia employs both modern and ancestral devices during cell division: it forms preprophase bands and in addition it shows centrosome-like polar organizers. We investigated whether polar organizers and preprophase bands cooperate to set up the division plane. To this end, two novel green fluorescent protein-based microtubule markers for dividing cells of Marchantia were developed. Cells of the apical notch formed polar organizers first and subsequently assembled preprophase bands. Polar organizers were formed de novo from multiple mobile microtubule foci localizing to the nuclear envelope. The foci then became concentrated by bipolar aggregation. We determined the comet production rate of polar organizers and show that microtubule plus ends of astral microtubules polymerize faster than those found on cortical microtubules. Importantly, it was observed that conditions increasing polar organizer numbers interfere with preprophase band formation. The data show that polar organizers have much in common with centrosomes, but that they also have specialized features. The results suggest that polar organizers contribute to preprophase band formation and in this way are involved in controlling the division plane. Our analyses of the basal land plant Marchantia shed new light on the evolution of plant cell division. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  12. Increased Cortical Inhibition in Autism-Linked Neuroligin-3R451C Mice Is Due in Part to Loss of Endocannabinoid Signaling.

    Science.gov (United States)

    Speed, Haley E; Masiulis, Irene; Gibson, Jay R; Powell, Craig M

    2015-01-01

    A single, maternally inherited, X-linked point mutation leading to an arginine to cysteine substitution at amino acid 451 (R451C) of Neuroligin 3 (NLGN3R451C) is a likely cause of autism in two brothers. Knockin mice expressing the Nlgn3R451C mutation in place of wild-type Nlgn3 demonstrate increased inhibitory synaptic strength in somatosensory cortex, resulting in an excitatory/inhibitory (E/I) imbalance that is potentially relevant for autism-associated behavioral deficits characteristic of these mice. We have replicated the increase in evoked inhibitory postsynaptic currents (eIPSCs) onto layer II/III cortical pyramidal neurons. We also find that increased frequency of spontaneous mIPSCs in Nlgn3R451C mice occurs in the absence of action potential-driven transmission. This suggests the E/I imbalance is due to changes at the synapse level, as opposed to the network level. Next, we use paired whole-cell recordings in an attempt to identify specific interneuron subtypes affected by the Nlgn3R451C mutation. Curiously, we observe no change in the amplitude of cell-to-cell, unitary IPSCs (uIPSCs) from parvalbumin-positive (PV) or somatostatin-positive (SOM) interneurons onto pyramidal neurons. We also observe no change in the number or density of PV and SOM interneurons in LII/III of somatosensory cortex. This effectively rules out a role for these particular interneurons in the increased inhibitory synaptic transmission, pointing to perhaps alternative interneuron subtypes. Lastly, impaired endocannabinoid signaling has been implicated in hippocampal synaptic dysfunction in Nlgn3R451C mice, but has not been investigated at cortical synapses. We find that bath application of the CB1 antagonist, AM 251 in WT mice eliminates the Nlgn3R451C increase in eIPSC amplitude and mIPSC frequency, indicating that increased inhibitory transmission in mutant mice is due, at least in part, to a loss of endocannabinoid signaling through CB1 receptors likely acting at interneurons

  13. Increased Cortical Inhibition in Autism-Linked Neuroligin-3R451C Mice Is Due in Part to Loss of Endocannabinoid Signaling.

    Directory of Open Access Journals (Sweden)

    Haley E Speed

    Full Text Available A single, maternally inherited, X-linked point mutation leading to an arginine to cysteine substitution at amino acid 451 (R451C of Neuroligin 3 (NLGN3R451C is a likely cause of autism in two brothers. Knockin mice expressing the Nlgn3R451C mutation in place of wild-type Nlgn3 demonstrate increased inhibitory synaptic strength in somatosensory cortex, resulting in an excitatory/inhibitory (E/I imbalance that is potentially relevant for autism-associated behavioral deficits characteristic of these mice. We have replicated the increase in evoked inhibitory postsynaptic currents (eIPSCs onto layer II/III cortical pyramidal neurons. We also find that increased frequency of spontaneous mIPSCs in Nlgn3R451C mice occurs in the absence of action potential-driven transmission. This suggests the E/I imbalance is due to changes at the synapse level, as opposed to the network level. Next, we use paired whole-cell recordings in an attempt to identify specific interneuron subtypes affected by the Nlgn3R451C mutation. Curiously, we observe no change in the amplitude of cell-to-cell, unitary IPSCs (uIPSCs from parvalbumin-positive (PV or somatostatin-positive (SOM interneurons onto pyramidal neurons. We also observe no change in the number or density of PV and SOM interneurons in LII/III of somatosensory cortex. This effectively rules out a role for these particular interneurons in the increased inhibitory synaptic transmission, pointing to perhaps alternative interneuron subtypes. Lastly, impaired endocannabinoid signaling has been implicated in hippocampal synaptic dysfunction in Nlgn3R451C mice, but has not been investigated at cortical synapses. We find that bath application of the CB1 antagonist, AM 251 in WT mice eliminates the Nlgn3R451C increase in eIPSC amplitude and mIPSC frequency, indicating that increased inhibitory transmission in mutant mice is due, at least in part, to a loss of endocannabinoid signaling through CB1 receptors likely acting at

  14. Discrimination of cortical laminae using MEG.

    Science.gov (United States)

    Troebinger, Luzia; López, José David; Lutti, Antoine; Bestmann, Sven; Barnes, Gareth

    2014-11-15

    Typically MEG source reconstruction is used to estimate the distribution of current flow on a single anatomically derived cortical surface model. In this study we use two such models representing superficial and deep cortical laminae. We establish how well we can discriminate between these two different cortical layer models based on the same MEG data in the presence of different levels of co-registration noise, Signal-to-Noise Ratio (SNR) and cortical patch size. We demonstrate that it is possible to make a distinction between superficial and deep cortical laminae for levels of co-registration noise of less than 2mm translation and 2° rotation at SNR > 11 dB. We also show that an incorrect estimate of cortical patch size will tend to bias layer estimates. We then use a 3D printed head-cast (Troebinger et al., 2014) to achieve comparable levels of co-registration noise, in an auditory evoked response paradigm, and show that it is possible to discriminate between these cortical layer models in real data. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

  15. Is cortical bone hip? What determines cortical bone properties?

    Science.gov (United States)

    Epstein, Sol

    2007-07-01

    Increased bone turnover may produce a disturbance in bone structure which may result in fracture. In cortical bone, both reduction in turnover and increase in hip bone mineral density (BMD) may be necessary to decrease hip fracture risk and may require relatively greater proportionate changes than for trabecular bone. It should also be noted that increased porosity produces disproportionate reduction in bone strength, and studies have shown that increased cortical porosity and decreased cortical thickness are associated with hip fracture. Continued studies for determining the causes of bone strength and deterioration show distinct promise. Osteocyte viability has been observed to be an indicator of bone strength, with viability as the result of maintaining physiological levels of loading and osteocyte apoptosis as the result of a decrease in loading. Osteocyte apoptosis and decrease are major factors in the bone loss and fracture associated with aging. Both the osteocyte and periosteal cell layer are assuming greater importance in the process of maintaining skeletal integrity as our knowledge of these cells expand, as well being a target for pharmacological agents to reduce fracture especially in cortical bone. The bisphosphonate alendronate has been seen to have a positive effect on cortical bone by allowing customary periosteal growth, while reducing the rate of endocortical bone remodeling and slowing bone loss from the endocortical surface. Risedronate treatment effects were attributed to decrease in bone resorption and thus a decrease in fracture risk. Ibandronate has been seen to increase BMD as the spine and femur as well as a reduced incidence of new vertebral fractures and non vertebral on subset post hoc analysis. And treatment with the anabolic agent PTH(1-34) documented modeling and remodelling of quiescent and active bone surfaces. Receptor activator of nuclear factor kappa B ligand (RANKL) plays a key role in bone destruction, and the human monoclonal

  16. Acute hypothalamic suppression significantly affects trabecular bone but not cortical bone following recovery and ovariectomy surgery in a rat model

    Directory of Open Access Journals (Sweden)

    Vanessa R. Yingling

    2016-01-01

    Full Text Available Background. Osteoporosis is “a pediatric disease with geriatric consequences.” Bone morphology and tissue quality co-adapt during ontogeny for sufficient bone stiffness. Altered bone morphology from hypothalamic amenorrhea, a risk factor for low bone mass in women, may affect bone strength later in life. Our purpose was to determine if altered morphology following hypothalamic suppression during development affects cortical bone strength and trabecular bone volume (BV/TV at maturity.Methods. Female rats (25 days old were assigned to a control (C group (n = 45 that received saline injections (.2 cc or an experimental group (GnRH-a (n = 45 that received gonadotropin releasing hormone antagonist injections (.24 mg per dose for 25 days. Fifteen animals from each group were sacrificed immediately after the injection protocol at Day 50 (C, GnRH-a. The remaining animals recovered for 135 days and a subset of each group was sacrificed at Day 185 ((C-R (n = 15 and (G-R (n = 15. The remaining animals had an ovariectomy surgery (OVX at 185 days of age and were sacrificed 40 days later (C-OVX (n = 15 and (G-OVX (n = 15. After sacrifice femurs were mechanically tested and scanned using micro CT. Serum C-terminal telopeptides (CTX and insulin-like growth factor 1 (IGF-1 were measured. Two-way ANOVA (2 groups (GnRH-a and Control X 3 time points (Injection Protocol, Recovery, post-OVX was computed.Results. GnRH-a injections suppressed uterine weights (72% and increased CTX levels by 59%. Bone stiffness was greater in the GnRH-a groups compared to C. Ash content and cortical bone area were similar between groups at all time points. Polar moment of inertia, a measure of bone architecture, was 15% larger in the GnRH-a group and remained larger than C (19% following recovery. Both the polar moment of inertia and cortical area increased linearly with the increases in body weight. Following the injection protocol, trabecular BV/TV was 31% lower in the Gn

  17. Effect of age at onset on cortical thickness and cognition in posterior cortical atrophy

    Science.gov (United States)

    Suárez-González, Aida; Lehmann, Manja; Shakespeare, Timothy J.; Yong, Keir X.X.; Paterson, Ross W.; Slattery, Catherine F.; Foulkes, Alexander J.M.; Rabinovici, Gil D.; Gil-Néciga, Eulogio; Roldán-Lora, Florinda; Schott, Jonathan M.; Fox, Nick C.; Crutch, Sebastian J.

    2016-01-01

    Age at onset (AAO) has been shown to influence the phenotype of Alzheimer’s disease (AD), but how it affects atypical presentations of AD remains unknown. Posterior cortical atrophy (PCA) is the most common form of atypical AD. In this study, we aimed to investigate the effect of AAO on cortical thickness and cognitive function in 98 PCA patients. We used Freesurfer (v5.3.0) to compare cortical thickness with AAO both as a continuous variable, and by dichotomizing the groups based on median age (58 years). In both the continuous and dichotomized analyses, we found a pattern suggestive of thinner cortex in precuneus and parietal areas in earlier-onset PCA, and lower cortical thickness in anterior cingulate and prefrontal cortex in later-onset PCA. These cortical thickness differences between PCA subgroups were consistent with earlier-onset PCA patients performing worse on cognitive tests involving parietal functions. Our results provide a suggestion that AAO may not only affect the clinico-anatomical characteristics in AD but may also affect atrophy patterns and cognition within atypical AD phenotypes. PMID:27318138

  18. Trajectories of cortical surface area and cortical volume maturation in normal brain development

    Directory of Open Access Journals (Sweden)

    Simon Ducharme

    2015-12-01

    Full Text Available This is a report of developmental trajectories of cortical surface area and cortical volume in the NIH MRI Study of Normal Brain Development. The quality-controlled sample included 384 individual typically-developing subjects with repeated scanning (1–3 per subject, total scans n=753 from 4.9 to 22.3 years of age. The best-fit model (cubic, quadratic, or first-order linear was identified at each vertex using mixed-effects models, with statistical correction for multiple comparisons using random field theory. Analyses were performed with and without controlling for total brain volume. These data are provided for reference and comparison with other databases. Further discussion and interpretation on cortical developmental trajectories can be found in the associated Ducharme et al.׳s article “Trajectories of cortical thickness maturation in normal brain development – the importance of quality control procedures” (Ducharme et al., 2015 [1].

  19. Focal cortical dysplasia – review

    International Nuclear Information System (INIS)

    Kabat, Joanna; Król, Przemysław

    2012-01-01

    Focal cortical dysplasia is a malformation of cortical development, which is the most common cause of medically refractory epilepsy in the pediatric population and the second/third most common etiology of medically intractable seizures in adults. Both genetic and acquired factors are involved in the pathogenesis of cortical dysplasia. Numerous classifications of the complex structural abnormalities of focal cortical dysplasia have been proposed – from Taylor et al. in 1971 to the last modification of Palmini classification made by Blumcke in 2011. In general, three types of cortical dysplasia are recognized. Type I focal cortical dysplasia with mild symptomatic expression and late onset, is more often seen in adults, with changes present in the temporal lobe. Clinical symptoms are more severe in type II of cortical dysplasia usually seen in children. In this type, more extensive changes occur outside the temporal lobe with predilection for the frontal lobes. New type III is one of the above dysplasias with associated another principal lesion as hippocampal sclerosis, tumor, vascular malformation or acquired pathology during early life. Brain MRI imaging shows abnormalities in the majority of type II dysplasias and in only some of type I cortical dysplasias. The most common findings on MRI imaging include: focal cortical thickening or thinning, areas of focal brain atrophy, blurring of the gray-white junction, increased signal on T2- and FLAIR-weighted images in the gray and subcortical white matter often tapering toward the ventricle. On the basis of the MRI findings, it is possible to differentiate between type I and type II cortical dysplasia. A complete resection of the epileptogenic zone is required for seizure-free life. MRI imaging is very helpful to identify those patients who are likely to benefit from surgical treatment in a group of patients with drug-resistant epilepsy. However, in type I cortical dysplasia, MR imaging is often normal, and also in both

  20. Polarization study of spiral galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Ward-Thompson, D

    1987-01-01

    Optical polarimetry results are presented for four spiral galaxies: NGC 5194 (M51), NGC 1068, NGC 4565 and NGC 4594 (M104). M51 and NGC 1068 show spiral polarization patterns interpreted as indicating a spiral magnetic field in each case. NGC 4565 and M104 show polarizations in their dust lanes which are parallel to their galactic planes, and which are interpreted in terms of a magnetic field in the plane of each. It is hypothesized that the observed magnetic fields may be linked to galactic shocks. A discussion of the origin of galactic magnetic fields concludes that there is not evidence that necessitates a primordial magnetic field.

  1. The hominoid-specific gene TBC1D3 promotes generation of basal neural progenitors and induces cortical folding in mice

    Science.gov (United States)

    Ju, Xiang-Chun; Hou, Qiong-Qiong; Sheng, Ai-Li; Wu, Kong-Yan; Zhou, Yang; Jin, Ying; Wen, Tieqiao; Yang, Zhengang; Wang, Xiaoqun; Luo, Zhen-Ge

    2016-01-01

    Cortical expansion and folding are often linked to the evolution of higher intelligence, but molecular and cellular mechanisms underlying cortical folding remain poorly understood. The hominoid-specific gene TBC1D3 undergoes segmental duplications during hominoid evolution, but its role in brain development has not been explored. Here, we found that expression of TBC1D3 in ventricular cortical progenitors of mice via in utero electroporation caused delamination of ventricular radial glia cells (vRGs) and promoted generation of self-renewing basal progenitors with typical morphology of outer radial glia (oRG), which are most abundant in primates. Furthermore, down-regulation of TBC1D3 in cultured human brain slices decreased generation of oRGs. Interestingly, localized oRG proliferation resulting from either in utero electroporation or transgenic expression of TBC1D3, was often found to underlie cortical regions exhibiting folding. Thus, we have identified a hominoid gene that is required for oRG generation in regulating the cortical expansion and folding. DOI: http://dx.doi.org/10.7554/eLife.18197.001 PMID:27504805

  2. PolarTREC: Successful Methods and Tools for Attaining Broad Educational Impacts with Interdisciplinary Polar Science

    Science.gov (United States)

    Timm, K. M.; Warburton, J.; Owens, R.; Warnick, W. K.

    2008-12-01

    PolarTREC--Teachers and Researchers Exploring and Collaborating, a program of the Arctic Research Consortium of the U.S. (ARCUS), is a National Science Foundation (NSF)-funded International Polar Year (IPY) project in which K-12 educators participate in hands-on field experiences in the polar regions, working closely with IPY scientists as a pathway to improving science education. Developing long-term teacher- researcher collaborations through PolarTREC ensures up-to-date climate change science content will permeate the K-12 education system long after the IPY. By infusing education with the cutting edge science from the polar regions, PolarTREC has already shown an increase in student and public knowledge of and interest in the polar regions and global climate change. Preliminary evaluations have shown that PolarTREC's program activities have many positive impacts on educators and their ability to teach science concepts and improve their teaching methods. Additionally, K-12 students polled in interest surveys showed significant changes regarding the importance of understanding the polar regions as a person in today's world. Researchers have been overwhelmingly satisfied with PolarTREC and cited several specific strengths, including the program's crucial link between the teachers' field research experiences and their classroom and the extensive training provided to teachers prior to their expedition. This presentation will focus on other successful components of the PolarTREC program and how researchers and organizations might use these tools to reach out to the public for long-term impacts. Best practices include strategies for working with educators and the development of an internet-based platform for teachers and researchers to interact with the public, combining several communication tools such as online journals and forums, real-time Internet seminars, lesson plans, activities, audio, and other educational resources that address a broad range of scientific

  3. Communication and Wiring in the Cortical Connectome

    Directory of Open Access Journals (Sweden)

    Julian eBudd

    2012-10-01

    Full Text Available In cerebral cortex, the huge mass of axonal wiring that carries information between near and distant neurons is thought to provide the neural substrate for cognitive and perceptual function. The goal of mapping the connectivity of cortical axons at different spatial scales, the cortical connectome, is to trace the paths of information flow in cerebral cortex. To appreciate the relationship between the connectome and cortical function, we need to discover the nature and purpose of the wiring principles underlying cortical connectivity. A popular explanation has been that axonal length is strictly minimized both within and between cortical regions. In contrast, we have hypothesized the existence of a multi-scale principle of cortical wiring where to optimise communication there is a trade-off between spatial (construction and temporal (routing costs. Here, using recent evidence concerning cortical spatial networks we critically evaluate this hypothesis at neuron, local circuit, and pathway scales. We report three main conclusions. First, the axonal and dendritic arbor morphology of single neocortical neurons may be governed by a similar wiring principle, one that balances the conservation of cellular material and conduction delay. Second, the same principle may be observed for fibre tracts connecting cortical regions. Third, the absence of sufficient local circuit data currently prohibits any meaningful assessment of the hypothesis at this scale of cortical organization. To avoid neglecting neuron and microcircuit levels of cortical organization, the connectome framework should incorporate more morphological description. In addition, structural analyses of temporal cost for cortical circuits should take account of both axonal conduction and neuronal integration delays, which appear mostly of the same order of magnitude. We conclude the hypothesized trade-off between spatial and temporal costs may potentially offer a powerful explanation for

  4. Perceptual learning and adult cortical plasticity.

    Science.gov (United States)

    Gilbert, Charles D; Li, Wu; Piech, Valentin

    2009-06-15

    The visual cortex retains the capacity for experience-dependent changes, or plasticity, of cortical function and cortical circuitry, throughout life. These changes constitute the mechanism of perceptual learning in normal visual experience and in recovery of function after CNS damage. Such plasticity can be seen at multiple stages in the visual pathway, including primary visual cortex. The manifestation of the functional changes associated with perceptual learning involve both long term modification of cortical circuits during the course of learning, and short term dynamics in the functional properties of cortical neurons. These dynamics are subject to top-down influences of attention, expectation and perceptual task. As a consequence, each cortical area is an adaptive processor, altering its function in accordance to immediate perceptual demands.

  5. Recognition of facial expressions by cortical multi-scale line and edge coding

    OpenAIRE

    Sousa, R.; Rodrigues, J. M. F.; du Buf, J. M. H.

    2010-01-01

    Face-to-face communications between humans involve emotions, which often are unconsciously conveyed by facial expressions and body gestures. Intelligent human-machine interfaces, for example in cognitive robotics, need to recognize emotions. This paper addresses facial expressions and their neural correlates on the basis of a model of the visual cortex: the multi-scale line and edge coding. The recognition model links the cortical representation with Paul Ekman's Action Units which are relate...

  6. A PKC-MARCKS-PI3K regulatory module links Ca2+ and PIP3 signals at the leading edge of polarized macrophages.

    Directory of Open Access Journals (Sweden)

    Brian P Ziemba

    Full Text Available The leukocyte chemosensory pathway detects attractant gradients and directs cell migration to sites of inflammation, infection, tissue damage, and carcinogenesis. Previous studies have revealed that local Ca2+ and PIP3 signals at the leading edge of polarized leukocytes play central roles in positive feedback loop essential to cell polarization and chemotaxis. These prior studies showed that stimulation of the leading edge Ca2+ signal can strongly activate PI3K, thereby triggering a larger PIP3 signal, but did not elucidate the mechanistic link between Ca2+ and PIP3 signaling. A hypothesis explaining this link emerged, postulating that Ca2+-activated PKC displaces the MARCKS protein from plasma membrane PIP2, thereby releasing sequestered PIP2 to serve as the target and substrate lipid of PI3K in PIP3 production. In vitro single molecule studies of the reconstituted pathway on lipid bilayers demonstrated the feasibility of this PKC-MARCKS-PI3K regulatory module linking Ca2+ and PIP3 signals in the reconstituted system. The present study tests the model predictions in live macrophages by quantifying the effects of: (a two pathway activators-PDGF and ATP that stimulate chemoreceptors and Ca2+ influx, respectively; and (b three pathway inhibitors-wortmannin, EGTA, and Go6976 that inhibit PI3K, Ca2+ influx, and PKC, respectively; on (c four leading edge activity sensors-AKT-PH-mRFP, CKAR, MARCKSp-mRFP, and leading edge area that report on PIP3 density, PKC activity, MARCKS membrane binding, and leading edge expansion/contraction, respectively. The results provide additional evidence that PKC and PI3K are both essential elements of the leading edge positive feedback loop, and strongly support the existence of a PKC-MARCKS-PI3K regulatory module linking the leading edge Ca2+ and PIP3 signals. As predicted, activators stimulate leading edge PKC activity, displacement of MARCKS from the leading edge membrane and increased leading edge PIP3 levels, while

  7. A PKC-MARCKS-PI3K regulatory module links Ca2+ and PIP3 signals at the leading edge of polarized macrophages.

    Science.gov (United States)

    Ziemba, Brian P; Falke, Joseph J

    2018-01-01

    The leukocyte chemosensory pathway detects attractant gradients and directs cell migration to sites of inflammation, infection, tissue damage, and carcinogenesis. Previous studies have revealed that local Ca2+ and PIP3 signals at the leading edge of polarized leukocytes play central roles in positive feedback loop essential to cell polarization and chemotaxis. These prior studies showed that stimulation of the leading edge Ca2+ signal can strongly activate PI3K, thereby triggering a larger PIP3 signal, but did not elucidate the mechanistic link between Ca2+ and PIP3 signaling. A hypothesis explaining this link emerged, postulating that Ca2+-activated PKC displaces the MARCKS protein from plasma membrane PIP2, thereby releasing sequestered PIP2 to serve as the target and substrate lipid of PI3K in PIP3 production. In vitro single molecule studies of the reconstituted pathway on lipid bilayers demonstrated the feasibility of this PKC-MARCKS-PI3K regulatory module linking Ca2+ and PIP3 signals in the reconstituted system. The present study tests the model predictions in live macrophages by quantifying the effects of: (a) two pathway activators-PDGF and ATP that stimulate chemoreceptors and Ca2+ influx, respectively; and (b) three pathway inhibitors-wortmannin, EGTA, and Go6976 that inhibit PI3K, Ca2+ influx, and PKC, respectively; on (c) four leading edge activity sensors-AKT-PH-mRFP, CKAR, MARCKSp-mRFP, and leading edge area that report on PIP3 density, PKC activity, MARCKS membrane binding, and leading edge expansion/contraction, respectively. The results provide additional evidence that PKC and PI3K are both essential elements of the leading edge positive feedback loop, and strongly support the existence of a PKC-MARCKS-PI3K regulatory module linking the leading edge Ca2+ and PIP3 signals. As predicted, activators stimulate leading edge PKC activity, displacement of MARCKS from the leading edge membrane and increased leading edge PIP3 levels, while inhibitors

  8. Basic visual function and cortical thickness patterns in posterior cortical atrophy.

    Science.gov (United States)

    Lehmann, Manja; Barnes, Josephine; Ridgway, Gerard R; Wattam-Bell, John; Warrington, Elizabeth K; Fox, Nick C; Crutch, Sebastian J

    2011-09-01

    Posterior cortical atrophy (PCA) is characterized by a progressive decline in higher-visual object and space processing, but the extent to which these deficits are underpinned by basic visual impairments is unknown. This study aimed to assess basic and higher-order visual deficits in 21 PCA patients. Basic visual skills including form detection and discrimination, color discrimination, motion coherence, and point localization were measured, and associations and dissociations between specific basic visual functions and measures of higher-order object and space perception were identified. All participants showed impairment in at least one aspect of basic visual processing. However, a number of dissociations between basic visual skills indicated a heterogeneous pattern of visual impairment among the PCA patients. Furthermore, basic visual impairments were associated with particular higher-order object and space perception deficits, but not with nonvisual parietal tasks, suggesting the specific involvement of visual networks in PCA. Cortical thickness analysis revealed trends toward lower cortical thickness in occipitotemporal (ventral) and occipitoparietal (dorsal) regions in patients with visuoperceptual and visuospatial deficits, respectively. However, there was also a lot of overlap in their patterns of cortical thinning. These findings suggest that different presentations of PCA represent points in a continuum of phenotypical variation.

  9. Effects of Aging on Cortical Neural Dynamics and Local Sleep Homeostasis in Mice.

    Science.gov (United States)

    McKillop, Laura E; Fisher, Simon P; Cui, Nanyi; Peirson, Stuart N; Foster, Russell G; Wafford, Keith A; Vyazovskiy, Vladyslav V

    2018-04-18

    Healthy aging is associated with marked effects on sleep, including its daily amount and architecture, as well as the specific EEG oscillations. Neither the neurophysiological underpinnings nor the biological significance of these changes are understood, and crucially the question remains whether aging is associated with reduced sleep need or a diminished capacity to generate sufficient sleep. Here we tested the hypothesis that aging may affect local cortical networks, disrupting the capacity to generate and sustain sleep oscillations, and with it the local homeostatic response to sleep loss. We performed chronic recordings of cortical neural activity and local field potentials from the motor cortex in young and older male C57BL/6J mice, during spontaneous waking and sleep, as well as during sleep after sleep deprivation. In older animals, we observed an increase in the incidence of non-rapid eye movement sleep local field potential slow waves and their associated neuronal silent (OFF) periods, whereas the overall pattern of state-dependent cortical neuronal firing was generally similar between ages. Furthermore, we observed that the response to sleep deprivation at the level of local cortical network activity was not affected by aging. Our data thus suggest that the local cortical neural dynamics and local sleep homeostatic mechanisms, at least in the motor cortex, are not impaired during healthy senescence in mice. This indicates that powerful protective or compensatory mechanisms may exist to maintain neuronal function stable across the life span, counteracting global changes in sleep amount and architecture. SIGNIFICANCE STATEMENT The biological significance of age-dependent changes in sleep is unknown but may reflect either a diminished sleep need or a reduced capacity to generate deep sleep stages. As aging has been linked to profound disruptions in cortical sleep oscillations and because sleep need is reflected in specific patterns of cortical activity, we

  10. Effect of age at onset on cortical thickness and cognition in posterior cortical atrophy.

    Science.gov (United States)

    Suárez-González, Aida; Lehmann, Manja; Shakespeare, Timothy J; Yong, Keir X X; Paterson, Ross W; Slattery, Catherine F; Foulkes, Alexander J M; Rabinovici, Gil D; Gil-Néciga, Eulogio; Roldán-Lora, Florinda; Schott, Jonathan M; Fox, Nick C; Crutch, Sebastian J

    2016-08-01

    Age at onset (AAO) has been shown to influence the phenotype of Alzheimer's disease (AD), but how it affects atypical presentations of AD remains unknown. Posterior cortical atrophy (PCA) is the most common form of atypical AD. In this study, we aimed to investigate the effect of AAO on cortical thickness and cognitive function in 98 PCA patients. We used Freesurfer (v5.3.0) to compare cortical thickness with AAO both as a continuous variable, and by dichotomizing the groups based on median age (58 years). In both the continuous and dichotomized analyses, we found a pattern suggestive of thinner cortex in precuneus and parietal areas in earlier-onset PCA, and lower cortical thickness in anterior cingulate and prefrontal cortex in later-onset PCA. These cortical thickness differences between PCA subgroups were consistent with earlier-onset PCA patients performing worse on cognitive tests involving parietal functions. Our results provide a suggestion that AAO may not only affect the clinico-anatomical characteristics in AD but may also affect atrophy patterns and cognition within atypical AD phenotypes. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  11. Reverse polarity optical-OFDM (RPO-OFDM): dimming compatible OFDM for gigabit VLC links.

    Science.gov (United States)

    Elgala, Hany; Little, Thomas D C

    2013-10-07

    Visible light communications (VLC) technology permits the exploitation of light-emitting diode (LED) luminaries for simultaneous illumination and broadband wireless communication. Optical orthogonal frequency-division multiplexing (O-OFDM) is a promising modulation technique for VLC systems, in which the real-valued O-OFDM baseband signal is used to modulate the instantaneous power of the optical carrier to achieve gigabit data rates. However, a major design challenge that limits the commercialization of VLC is how to incorporate the industry-preferred pulse-width modulation (PWM) light dimming technique while maintaining a broadband and reliable communication link. In this work, a novel signal format, reverse polarity O-OFDM (RPO-OFDM), is proposed to combine the fast O-OFDM communication signal with the relatively slow PWM dimming signal, where both signals contribute to the effective LED brightness. The advantages of using RPO-OFDM include, (1) the data rate is not limited by the frequency of the PWM signal, (2) the LED dynamic range is fully utilized to minimize the nonlinear distortion of the O-OFDM communication signal, and (3) the bit-error performance is sustained over a large fraction of the luminaire dimming range. In addition, RPO-OFDM offers a practical approach to utilize off-the-shelf LED drivers. We show results of numerical simulations to study the trade-offs between the PWM duty cycle, average electrical O-OFDM signal power, radiated optical flux as well as human perceived light.

  12. SynGAP regulates protein synthesis and homeostatic synaptic plasticity in developing cortical networks.

    Directory of Open Access Journals (Sweden)

    Chih-Chieh Wang

    Full Text Available Disrupting the balance between excitatory and inhibitory neurotransmission in the developing brain has been causally linked with intellectual disability (ID and autism spectrum disorders (ASD. Excitatory synapse strength is regulated in the central nervous system by controlling the number of postsynaptic α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs. De novo genetic mutations of the synaptic GTPase-activating protein (SynGAP are associated with ID and ASD. SynGAP is enriched at excitatory synapses and genetic suppression of SynGAP increases excitatory synaptic strength. However, exactly how SynGAP acts to maintain synaptic AMPAR content is unclear. We show here that SynGAP limits excitatory synaptic strength, in part, by suppressing protein synthesis in cortical neurons. The data presented here from in vitro, rat and mouse cortical networks, demonstrate that regulation of translation by SynGAP involves ERK, mTOR, and the small GTP-binding protein Rheb. Furthermore, these data show that GluN2B-containing NMDARs and the cognitive kinase CaMKII act upstream of SynGAP and that this signaling cascade is required for proper translation-dependent homeostatic synaptic plasticity of excitatory synapses in developing cortical networks.

  13. Microtubule-targeting drugs rescue axonal swellings in cortical neurons from spastin knockout mice

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    Coralie Fassier

    2013-01-01

    Mutations in SPG4, encoding the microtubule-severing protein spastin, are responsible for the most frequent form of hereditary spastic paraplegia (HSP, a heterogeneous group of genetic diseases characterized by degeneration of the corticospinal tracts. We previously reported that mice harboring a deletion in Spg4, generating a premature stop codon, develop progressive axonal degeneration characterized by focal axonal swellings associated with impaired axonal transport. To further characterize the molecular and cellular mechanisms underlying this mutant phenotype, we have assessed microtubule dynamics and axonal transport in primary cultures of cortical neurons from spastin-mutant mice. We show an early and marked impairment of microtubule dynamics all along the axons of spastin-deficient cortical neurons, which is likely to be responsible for the occurrence of axonal swellings and cargo stalling. Our analysis also reveals that a modulation of microtubule dynamics by microtubule-targeting drugs rescues the mutant phenotype of cortical neurons. Together, these results contribute to a better understanding of the pathogenesis of SPG4-linked HSP and ascertain the influence of microtubule-targeted drugs on the early axonal phenotype in a mouse model of the disease.

  14. A genome-wide search for quantitative trait loci affecting the cortical surface area and thickness of Heschl's gyrus

    NARCIS (Netherlands)

    Cai, D.C.; Fonteijn, H.M.; Guadalupe, T.M.; Zwiers, M.P.; Wittfeld, K.; Teumer, A.; Hoogman, M.; Arias Vasquez, A.; Yang, Y; Buitelaar, J.K.; Fernandez, G.S.E.; Brunner, H.G.; Bokhoven, H. van; Franke, B.; Hegenscheid, K.; Homuth, G.; Fisher, S.E.; Grabe, H.J.; Francks, C.; Hagoort, P.

    2014-01-01

    Heschl's gyrus (HG) is a core region of the auditory cortex whose morphology is highly variable across individuals. This variability has been linked to sound perception ability in both speech and music domains. Previous studies show that variations in morphological features of HG, such as cortical

  15. Inferior frontal gyrus links visual and motor cortices during a visuomotor precision grip force task.

    Science.gov (United States)

    Papadelis, Christos; Arfeller, Carola; Erla, Silvia; Nollo, Giandomenico; Cattaneo, Luigi; Braun, Christoph

    2016-11-01

    Coordination between vision and action relies on a fronto-parietal network that receives visual and proprioceptive sensory input in order to compute motor control signals. Here, we investigated with magnetoencephalography (MEG) which cortical areas are functionally coupled on the basis of synchronization during visuomotor integration. MEG signals were recorded from twelve healthy adults while performing a unimanual visuomotor (VM) task and control conditions. The VM task required the integration of pinch motor commands with visual sensory feedback. By using a beamformer, we localized the neural activity in the frequency range of 1-30Hz during the VM compared to rest. Virtual sensors were estimated at the active locations. A multivariate autoregressive model was used to estimate the power and coherence of estimated activity at the virtual sensors. Event-related desynchronisation (ERD) during VM was observed in early visual areas, the rostral part of the left inferior frontal gyrus (IFG), the right IFG, the superior parietal lobules, and the left hand motor cortex (M1). Functional coupling in the alpha frequency band bridged the regional activities observed in motor and visual cortices (the start and the end points in the visuomotor loop) through the left or right IFG. Coherence between the left IFG and left M1 correlated inversely with the task performance. Our results indicate that an occipital-prefrontal-motor functional network facilitates the modulation of instructed motor responses to visual cues. This network may supplement the mechanism for guiding actions that is fully incorporated into the dorsal visual stream. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Cortical feedback control of olfactory bulb circuits.

    Science.gov (United States)

    Boyd, Alison M; Sturgill, James F; Poo, Cindy; Isaacson, Jeffry S

    2012-12-20

    Olfactory cortex pyramidal cells integrate sensory input from olfactory bulb mitral and tufted (M/T) cells and project axons back to the bulb. However, the impact of cortical feedback projections on olfactory bulb circuits is unclear. Here, we selectively express channelrhodopsin-2 in olfactory cortex pyramidal cells and show that cortical feedback projections excite diverse populations of bulb interneurons. Activation of cortical fibers directly excites GABAergic granule cells, which in turn inhibit M/T cells. However, we show that cortical inputs preferentially target short axon cells that drive feedforward inhibition of granule cells. In vivo, activation of olfactory cortex that only weakly affects spontaneous M/T cell firing strongly gates odor-evoked M/T cell responses: cortical activity suppresses odor-evoked excitation and enhances odor-evoked inhibition. Together, these results indicate that although cortical projections have diverse actions on olfactory bulb microcircuits, the net effect of cortical feedback on M/T cells is an amplification of odor-evoked inhibition. Copyright © 2012 Elsevier Inc. All rights reserved.

  17. Cortical myoclonus and cerebellar pathology

    NARCIS (Netherlands)

    Tijssen, MAJ; Thom, M; Ellison, DW; Wilkins, P; Barnes, D; Thompson, PD; Brown, P

    2000-01-01

    Objective To study the electrophysiologic and pathologic findings in three patients with cortical myoclonus. In two patients the myoclonic ataxic syndrome was associated with proven celiac disease. Background: The pathologic findings in conditions associated with cortical myoclonus commonly involve

  18. Cortical myoclonus and cerebellar pathology

    NARCIS (Netherlands)

    Tijssen, M. A.; Thom, M.; Ellison, D. W.; Wilkins, P.; Barnes, D.; Thompson, P. D.; Brown, P.

    2000-01-01

    OBJECTIVE: To study the electrophysiologic and pathologic findings in three patients with cortical myoclonus. In two patients the myoclonic ataxic syndrome was associated with proven celiac disease. BACKGROUND: The pathologic findings in conditions associated with cortical myoclonus commonly involve

  19. Trichinella and polar bears: a limited risk for humans.

    Science.gov (United States)

    Dupouy-Camet, J; Bourée, P; Yera, H

    2017-07-01

    In this review, we identified 63 cases reported since World War II of human trichinellosis linked to the consumption of parasitized polar bear (Ursus maritimus) meat. This low number contrasts to the numerous cases of human trichinellosis related to consumption of the meat of black (U. americanus) or brown bears (U. arctos). The prevalence of Trichinella infection is high in bears, but larval muscular burden is usually lower in polar bears compared to other bear species. Polar bears, therefore, seem to play a limited role in the transmission of trichinellosis to humans, as native residents living in the Arctic traditionally consume well-cooked bear meat, and travellers and foreign hunters have only limited access to this protected species due to the declining polar bear population.

  20. Dynamics of myosin II organization into cortical contractile networks and fibers

    Science.gov (United States)

    Nie, Wei; Wei, Ming-Tzo; Ou-Yang, Daniel; Jedlicka, Sabrina; Vavylonis, Dimitrios

    2014-03-01

    The morphology of adhered cells critically depends on the formation of a contractile meshwork of parallel and cross-linked stress fibers along the contacting surface. The motor activity and mini-filament assembly of non-muscle myosin II is an important component of cell-level cytoskeletal remodeling during mechanosensing. To monitor the dynamics of myosin II, we used confocal microscopy to image cultured HeLa cells that stably express myosin regulatory light chain tagged with GFP (MRLC-GFP). MRLC-GFP was monitored in time-lapse movies at steady state and during the response of cells to varying concentrations of blebbistatin which disrupts actomyosin stress fibers. Using image correlation spectroscopy analysis, we quantified the kinetics of disassembly and reassembly of actomyosin networks and compared them to studies by other groups. This analysis suggested that the following processes contribute to the assembly of cortical actomyosin into fibers: random myosin mini-filament assembly and disassembly along the cortex; myosin mini-filament aligning and contraction; stabilization of cortical myosin upon increasing contractile tension. We developed simple numerical simulations that include those processes. The results of simulations of cells at steady state and in response to blebbistatin capture some of the main features observed in the experiments. This study provides a framework to help interpret how different cortical myosin remodeling kinetics may contribute to different cell shape and rigidity depending on substrate stiffness.

  1. Development of cortical asymmetry in typically developing children and its disruption in attention-deficit/hyperactivity disorder.

    Science.gov (United States)

    Shaw, Philip; Lalonde, Francois; Lepage, Claude; Rabin, Cara; Eckstrand, Kristen; Sharp, Wendy; Greenstein, Deanna; Evans, Alan; Giedd, J N; Rapoport, Judith

    2009-08-01

    Just as typical development of anatomical asymmetries in the human brain has been linked with normal lateralization of motor and cognitive functions, disruption of asymmetry has been implicated in the pathogenesis of neurodevelopmental disorders such as attention-deficit/hyperactivity disorder (ADHD). No study has examined the development of cortical asymmetry using longitudinal neuroanatomical data. To delineate the development of cortical asymmetry in children with and without ADHD. Longitudinal study. Government Clinical Research Institute. A total of 218 children with ADHD and 358 typically developing children, from whom 1133 neuroanatomical magnetic resonance images were acquired prospectively. Cortical thickness was estimated at 40 962 homologous points in the left and right hemispheres, and the trajectory of change in asymmetry was defined using mixed-model regression. In right-handed typically developing individuals, a mean (SE) increase in the relative thickness of the right orbitofrontal and inferior frontal cortex with age of 0.011 (0.0018) mm per year (t(337) = 6.2, P left-hemispheric increase in the occipital cortical regions of 0.013 (0.0015) mm per year (t(337) = 8.1, P right-handed typically developing individuals was less extensive and was localized to different cortical regions. In ADHD, the posterior component of this evolving asymmetry was intact, but the prefrontal component was lost. These findings explain the way that, in typical development, the increased dimensions of the right frontal and left occipital cortical regions emerge in adulthood from the reversed pattern of childhood cortical asymmetries. Loss of the prefrontal component of this evolving asymmetry in ADHD is compatible with disruption of prefrontal function in the disorder and demonstrates the way that disruption of typical processes of asymmetry can inform our understanding of neurodevelopmental disorders.

  2. Uncovering the link between malfunctions in Drosophila neuroblast asymmetric cell division and tumorigenesis

    Directory of Open Access Journals (Sweden)

    Kelsom Corey

    2012-11-01

    Full Text Available Abstract Asymmetric cell division is a developmental process utilized by several organisms. On the most basic level, an asymmetric division produces two daughter cells, each possessing a different identity or fate. Drosophila melanogaster progenitor cells, referred to as neuroblasts, undergo asymmetric division to produce a daughter neuroblast and another cell known as a ganglion mother cell (GMC. There are several features of asymmetric division in Drosophila that make it a very complex process, and these aspects will be discussed at length. The cell fate determinants that play a role in specifying daughter cell fate, as well as the mechanisms behind setting up cortical polarity within neuroblasts, have proved to be essential to ensuring that neurogenesis occurs properly. The role that mitotic spindle orientation plays in coordinating asymmetric division, as well as how cell cycle regulators influence asymmetric division machinery, will also be addressed. Most significantly, malfunctions during asymmetric cell division have shown to be causally linked with neoplastic growth and tumor formation. Therefore, it is imperative that the developmental repercussions as a result of asymmetric cell division gone awry be understood.

  3. Cortical thickness, surface area, and folding alterations in male youths with conduct disorder and varying levels of callous-unemotional traits.

    Science.gov (United States)

    Fairchild, Graeme; Toschi, Nicola; Hagan, Cindy C; Goodyer, Ian M; Calder, Andrew J; Passamonti, Luca

    2015-01-01

    Previous studies have reported changes in gray matter volume in youths with conduct disorder (CD), although these differences are difficult to interpret as they may have been driven by alterations in cortical thickness, surface area (SA), or folding. The objective of this study was to use surface-based morphometry (SBM) methods to compare male youths with CD and age and sex-matched healthy controls (HCs) in cortical thickness, SA, and folding. We also tested for structural differences between the childhood-onset and adolescence-onset subtypes of CD and performed regression analyses to assess for relationships between CD symptoms and callous-unemotional (CU) traits and SBM-derived measures. We acquired structural neuroimaging data from 20 HCs and 36 CD participants (18 with childhood-onset CD and 18 with adolescence-onset CD) and analyzed the data using FreeSurfer. Relative to HCs, youths with CD showed reduced cortical thickness in the superior temporal gyrus, reduced SA in the orbitofrontal cortex (OFC), and increased cortical folding in the insula. There were no significant differences between the childhood-onset and adolescence-onset CD subgroups in cortical thickness or SA, but several frontal and temporal regions showed increased cortical folding in childhood-onset relative to adolescence-onset CD participants. Both CD subgroups also showed increased cortical folding relative to HCs. CD symptoms were negatively correlated with OFC SA whereas CU traits were positively correlated with insula folding. Cortical thinning in the superior temporal gyrus may contribute to the social cognitive impairments displayed by youths with CD, whereas reduced OFC SA may lead to impairments in emotion regulation and reward processing in youths with CD. The increased cortical folding observed in the insula may reflect a maturational delay in this region and could mediate the link between CU traits and empathy deficits. Altered cortical folding was observed in childhood-onset and

  4. Pharmacological modulation of cortical excitability shifts induced by transcranial direct current stimulation in humans.

    Science.gov (United States)

    Nitsche, M A; Fricke, K; Henschke, U; Schlitterlau, A; Liebetanz, D; Lang, N; Henning, S; Tergau, F; Paulus, W

    2003-11-15

    Transcranial direct current stimulation (tDCS) of the human motor cortex results in polarity-specific shifts of cortical excitability during and after stimulation. Anodal tDCS enhances and cathodal stimulation reduces excitability. Animal experiments have demonstrated that the effect of anodal tDCS is caused by neuronal depolarisation, while cathodal tDCS hyperpolarises cortical neurones. However, not much is known about the ion channels and receptors involved in these effects. Thus, the impact of the sodium channel blocker carbamazepine, the calcium channel blocker flunarizine and the NMDA receptor antagonist dextromethorphane on tDCS-elicited motor cortical excitability changes of healthy human subjects were tested. tDCS-protocols inducing excitability alterations (1) only during tDCS and (2) eliciting long-lasting after-effects were applied after drug administration. Carbamazepine selectively eliminated the excitability enhancement induced by anodal stimulation during and after tDCS. Flunarizine resulted in similar changes. Antagonising NMDA receptors did not alter current-generated excitability changes during a short stimulation, which elicits no after-effects, but prevented the induction of long-lasting after-effects independent of their direction. These results suggest that, like in other animals, cortical excitability shifts induced during tDCS in humans also depend on membrane polarisation, thus modulating the conductance of sodium and calcium channels. Moreover, they suggest that the after-effects may be NMDA receptor dependent. Since NMDA receptors are involved in neuroplastic changes, the results suggest a possible application of tDCS in the modulation or induction of these processes in a clinical setting. The selective elimination of tDCS-driven excitability enhancements by carbamazepine proposes a role for this drug in focussing the effects of cathodal tDCS, which may have important future clinical applications.

  5. Measured results of polarization crosstalk cancellation using LMS control. [Least Mean Square

    Science.gov (United States)

    Baird, C. A.; Rassweiler, G. G.

    1977-01-01

    This paper discusses the use of wideband decoupling networks for the cancellation of polarization crosstalk in dual-polarized communication links. Measured cancellation performance for an all-electronic IF network and an RF electro-mechanical waveguide network are presented. Each of these networks utilizes LMS-type adaptive control techniques to adjust the cancellation network.

  6. Evolving Models of Pavlovian Conditioning: Cerebellar Cortical Dynamics in Awake Behaving Mice

    Directory of Open Access Journals (Sweden)

    Michiel M. ten Brinke

    2015-12-01

    Full Text Available Three decades of electrophysiological research on cerebellar cortical activity underlying Pavlovian conditioning have expanded our understanding of motor learning in the brain. Purkinje cell simple spike suppression is considered to be crucial in the expression of conditional blink responses (CRs. However, trial-by-trial quantification of this link in awake behaving animals is lacking, and current hypotheses regarding the underlying plasticity mechanisms have diverged from the classical parallel fiber one to the Purkinje cell synapse LTD hypothesis. Here, we establish that acquired simple spike suppression, acquired conditioned stimulus (CS-related complex spike responses, and molecular layer interneuron (MLI activity predict the expression of CRs on a trial-by-trial basis using awake behaving mice. Additionally, we show that two independent transgenic mouse mutants with impaired MLI function exhibit motor learning deficits. Our findings suggest multiple cerebellar cortical plasticity mechanisms underlying simple spike suppression, and they implicate the broader involvement of the olivocerebellar module within the interstimulus interval.

  7. Luminance and chromatic contributions to a hyperacuity task: isolation by contrast polarity and target separation.

    Science.gov (United States)

    Sun, Hao; Cooper, Bonnie; Lee, Barry B

    2012-03-01

    Vernier thresholds are known to be elevated when a target pair has opposite contrast polarity. Polarity reversal is used to assess the role of luminance and chromatic pathways in hyperacuity performance. Psychophysical hyperacuity thresholds were measured for pairs of gratings of various combinations of luminance (Lum) and chromatic (Chr) contrast polarities, at different ratios of luminance to chromatic contrast. With two red-green gratings of matched luminance and chromatic polarity (+Lum+Chr), there was an elevation of threshold at isoluminance. When both luminance and chromatic polarity were mismatched (-Lum-Chr), thresholds were substantially elevated under all conditions. With the same luminance contrast polarity and opposite chromatic polarity (+Lum-Chr) thresholds were only elevated close to isoluminance; in the reverse condition (-Lum+Chr), thresholds were elevated as in the -Lum-Chr condition except close to equiluminance. Similar data were obtained for gratings isolating the short-wavelength cone mechanism. Further psychophysical measurements assessed the role of target separation with matched or mismatched contrast polarity; similar results were found for luminance and chromatic gratings. Comparison physiological data were collected from parafoveal ganglion cells of the macaque retina. Positional precision of ganglion cell signals was assessed under conditions related to the psychophysical measurements. On the basis of these combined observations, it is argued that both magnocellular, parvocellular, and koniocellular pathways have access to cortical positional mechanisms associated with vernier acuity. Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. Adaptations in the Microarchitecture and Load Distribution of Maternal Cortical and Trabecular Bone in Response to Multiple Reproductive Cycles in Rats

    Science.gov (United States)

    de Bakker, Chantal M. J.; Altman-Singles, Allison R.; Li, Yihan; Tseng, Wei-Ju; Li, Connie; Liu, X. Sherry

    2017-01-01

    Pregnancy, lactation, and weaning result in dramatic changes in maternal calcium metabolism. In particular, the increased calcium demand during lactation causes a substantial degree of maternal bone loss. This reproductive bone loss has been suggested to be largely reversible, as multiple clinical studies have found that parity and lactation history have no adverse effect on post-menopausal fracture risk. However, the precise effects of pregnancy, lactation, and post-weaning recovery on maternal bone structure are not well understood. Our study aimed to address this question by longitudinally tracking changes in trabecular and cortical bone microarchitecture at the proximal tibia in rats throughout three cycles of pregnancy, lactation, and post-weaning using in vivo μCT. We found that the trabecular thickness underwent a reversible deterioration during pregnancy and lactation, which was fully recovered after weaning, while other parameters of trabecular microarchitecture (including trabecular number, spacing, connectivity density, and structure model index) underwent a more permanent deterioration which recovered minimally. Thus, pregnancy and lactation resulted in both transient and long-lasting alterations in trabecular microstructure. In the meantime, multiple reproductive cycles appeared to improve the robustness of cortical bone (resulting in an elevated cortical area and polar moment of inertia), as well as increase the proportion of the total load carried by the cortical bone at the proximal tibia. Taken together, changes in the cortical and trabecular compartments suggest that while rat tibial trabecular bone appears to be highly involved in maintaining calcium homeostasis during female reproduction, cortical bone adapts to increase its load-bearing capacity, allowing the overall mechanical function of the tibia to be maintained. PMID:28109138

  9. Cortical dendritic activity correlates with spindle-rich oscillations during sleep in rodents.

    Science.gov (United States)

    Seibt, Julie; Richard, Clément J; Sigl-Glöckner, Johanna; Takahashi, Naoya; Kaplan, David I; Doron, Guy; de Limoges, Denis; Bocklisch, Christina; Larkum, Matthew E

    2017-09-25

    How sleep influences brain plasticity is not known. In particular, why certain electroencephalographic (EEG) rhythms are linked to memory consolidation is poorly understood. Calcium activity in dendrites is known to be necessary for structural plasticity changes, but this has never been carefully examined during sleep. Here, we report that calcium activity in populations of neocortical dendrites is increased and synchronised during oscillations in the spindle range in naturally sleeping rodents. Remarkably, the same relationship is not found in cell bodies of the same neurons and throughout the cortical column. Spindles during sleep have been suggested to be important for brain development and plasticity. Our results provide evidence for a physiological link of spindles in the cortex specific to dendrites, the main site of synaptic plasticity.Different stages of sleep, marked by particular electroencephalographic (EEG) signatures, have been linked to memory consolidation, but underlying mechanisms are poorly understood. Here, the authors show that dendritic calcium synchronisation correlates with spindle-rich sleep phases.

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

    Science.gov (United States)

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

    2017-06-06

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

  11. Rehabilitation-triggered cortical plasticity after stroke: in vivo imaging at multiple scales (Conference Presentation)

    Science.gov (United States)

    Allegra Mascaro, Anna Letizia; Conti, Emilia; Lai, Stefano; Spalletti, Cristina; Di Giovanna, Antonino Paolo; Alia, Claudia; Panarese, Alessandro; Sacconi, Leonardo; Micera, Silvestro; Caleo, Matteo; Pavone, Francesco S.

    2017-02-01

    Neurorehabilitation protocols based on the use of robotic devices provide a highly repeatable therapy and have recently shown promising clinical results. Little is known about how rehabilitation molds the brain to promote motor recovery of the affected limb. We used a custom-made robotic platform that provides quantitative assessment of forelimb function in a retraction test. Complementary imaging techniques allowed us to access to the multiple facets of robotic rehabilitation-induced cortical plasticity after unilateral photothrombotic stroke in mice Primary Motor Cortex (Caudal Forelimb Area - CFA). First, we analyzed structural features of vasculature and dendritic reshaping in the peri-infarct area with two-photon fluorescence microscopy. Longitudinal analysis of dendritic branches and spines of pyramidal neurons suggests that robotic rehabilitation promotes the stabilization of peri-infarct cortical excitatory circuits, which is not accompanied by consistent vascular reorganization towards pre-stroke conditions. To investigate if this structural stabilization was linked to functional remapping, we performed mesoscale wide-field imaging on GCaMP6 mice while performing the motor task on the robotic platform. We revealed temporal and spatial features of the motor-triggered cortical activation, shining new light on rehabilitation-induced functional remapping of the ipsilesional cortex. Finally, by using an all-optical approach that combines optogenetic activation of the contralesional hemisphere and wide-field functional imaging of peri-infarct area, we dissected the effect of robotic rehabilitation on inter-hemispheric cortico-cortical connectivity.

  12. Hypothesis-driven methods to augment human cognition by optimizing cortical oscillations

    Directory of Open Access Journals (Sweden)

    Jörn M. Horschig

    2014-06-01

    Full Text Available Cortical oscillations have been shown to represent fundamental functions of a working brain, e.g. communication, stimulus binding, error monitoring, and inhibition, and are directly linked to behavior. Recent studies intervening with these oscillations have demonstrated effective modulation of both the oscillations and behavior. In this review, we collect evidence in favor of how hypothesis-driven methods can be used to augment cognition by optimizing cortical oscillations. We elaborate their potential usefulness for three target groups: healthy elderly, patients with attention deficit/hyperactivity disorder, and healthy young adults. We discuss the relevance of neuronal oscillations in each group and show how each of them can benefit from the manipulation of functionally-related oscillations. Further, we describe methods for manipulation of neuronal oscillations including direct brain stimulation as well as indirect task alterations. We also discuss practical considerations about the proposed techniques. In conclusion, we propose that insights from neuroscience should guide techniques to augment human cognition, which in turn can provide a better understanding of how the human brain works.

  13. Axons Pull on the Brain, But Tension Does Not Drive Cortical Folding

    Science.gov (United States)

    Xu, Gang; Knutsen, Andrew K.; Dikranian, Krikor; Kroenke, Christopher D.; Bayly, Philip V.; Taber, Larry A.

    2011-01-01

    During human brain development, the cerebral cortex undergoes substantial folding, leading to its characteristic highly convoluted form. Folding is necessary to accommodate the expansion of the cerbral cortex; abnormal cortical folding is linked to various neurological disorders, including schizophrenia, epilepsy, autism and mental retardation. Although this process requires mechanical forces, the specific force-generating mechanisms that drive folding remain unclear. The two most widely accepted hypotheses are (1) folding is caused by differential growth of the cortex and (2) folding is caused by mechanical tension generated in axons. Direct evidence supporting either theory, however, is lacking. Here we show that axons are indeed under considerable tension in the developing ferret brain, but the patterns of tissue stress are not consistent with a causal role for axonal tension. In particular, microdissection assays reveal that significant tension exists along axons aligned circumferentially in subcortical white matter tracts, as well as those aligned radially inside developing gyri (outward folds). Contrary to previous speculation, however, axonal tension is not directed across developing gyri, suggesting that axon tension does not drive folding. On the other hand, using computational (finite element) models, we show that differential cortical growth accompanied by remodeling of the subplate leads to outward folds and stress fields that are consistent with our microdissection experiments, supporting a mechanism involving differential growth. Local perturbations, such as temporal differences in the initiation of cortical growth, can ensure consistent folding patterns. This study shows that a combination of experimental and computational mechanics can be used to evaluate competing hypotheses of morphogenesis, and illuminate the biomechanics of cortical folding. PMID:20590291

  14. State-dependent intrinsic predictability of cortical network dynamics.

    Directory of Open Access Journals (Sweden)

    Leila Fakhraei

    Full Text Available The information encoded in cortical circuit dynamics is fleeting, changing from moment to moment as new input arrives and ongoing intracortical interactions progress. A combination of deterministic and stochastic biophysical mechanisms governs how cortical dynamics at one moment evolve from cortical dynamics in recently preceding moments. Such temporal continuity of cortical dynamics is fundamental to many aspects of cortex function but is not well understood. Here we study temporal continuity by attempting to predict cortical population dynamics (multisite local field potential based on its own recent history in somatosensory cortex of anesthetized rats and in a computational network-level model. We found that the intrinsic predictability of cortical dynamics was dependent on multiple factors including cortical state, synaptic inhibition, and how far into the future the prediction extends. By pharmacologically tuning synaptic inhibition, we obtained a continuum of cortical states with asynchronous population activity at one extreme and stronger, spatially extended synchrony at the other extreme. Intermediate between these extremes we observed evidence for a special regime of population dynamics called criticality. Predictability of the near future (10-100 ms increased as the cortical state was tuned from asynchronous to synchronous. Predictability of the more distant future (>1 s was generally poor, but, surprisingly, was higher for asynchronous states compared to synchronous states. These experimental results were confirmed in a computational network model of spiking excitatory and inhibitory neurons. Our findings demonstrate that determinism and predictability of network dynamics depend on cortical state and the time-scale of the dynamics.

  15. Polarization-Resolved Study of High Harmonics from Bulk Semiconductors

    Science.gov (United States)

    Kaneshima, Keisuke; Shinohara, Yasushi; Takeuchi, Kengo; Ishii, Nobuhisa; Imasaka, Kotaro; Kaji, Tomohiro; Ashihara, Satoshi; Ishikawa, Kenichi L.; Itatani, Jiro

    2018-06-01

    The polarization property of high harmonics from gallium selenide is investigated using linearly polarized midinfrared laser pulses. With a high electric field, the perpendicular polarization component of the odd harmonics emerges, which is not present with a low electric field and cannot be explained by the perturbative nonlinear optics. A two-dimensional single-band model is developed to show that the anisotropic curvature of an energy band of solids, which is pronounced in an outer part of the Brillouin zone, induces the generation of the perpendicular odd harmonics. This model is validated by three-dimensional quantum mechanical simulations, which reproduce the orientation dependence of the odd-order harmonics. The quantum mechanical simulations also reveal that the odd- and even-order harmonics are produced predominantly by the intraband current and interband polarization, respectively. These experimental and theoretical demonstrations clearly show a strong link between the band structure of a solid and the polarization property of the odd-order harmonics.

  16. Frequency and Polarization Diversity Jamming of Communications in Urban Environments

    National Research Council Canada - National Science Library

    Ulama, Tuncay

    2005-01-01

    The purpose of this research is to investigate how to exploit frequency and polarization techniques in reducing the effects of jamming against UAV relay communication links in an urban warfare environment...

  17. Positive Association between Cognitive Ability and Cortical Thickness in a Representative US Sample of Healthy 6 to 18 Year-Olds

    Science.gov (United States)

    Karama, S.; Ad-Dab'bagh, Y.; Haier, R. J.; Deary, I. J.; Lyttelton, O. C.; Lepage, C.; Evans, A. C.

    2009-01-01

    Neuroimaging studies, using various modalities, have evidenced a link between the general intelligence factor (g) and regional brain function and structure in several multimodal association areas. While in the last few years, developments in computational neuroanatomy have made possible the "in vivo" quantification of cortical thickness, the…

  18. The biology and dynamics of mammalian cortical granules

    Directory of Open Access Journals (Sweden)

    Liu Min

    2011-11-01

    Full Text Available Abstract Cortical granules are membrane bound organelles located in the cortex of unfertilized oocytes. Following fertilization, cortical granules undergo exocytosis to release their contents into the perivitelline space. This secretory process, which is calcium dependent and SNARE protein-mediated pathway, is known as the cortical reaction. After exocytosis, the released cortical granule proteins are responsible for blocking polyspermy by modifying the oocytes' extracellular matrices, such as the zona pellucida in mammals. Mammalian cortical granules range in size from 0.2 um to 0.6 um in diameter and different from most other regulatory secretory organelles in that they are not renewed once released. These granules are only synthesized in female germ cells and transform an egg upon sperm entry; therefore, this unique cellular structure has inherent interest for our understanding of the biology of fertilization. Cortical granules are long thought to be static and awaiting in the cortex of unfertilized oocytes to be stimulated undergoing exocytosis upon gamete fusion. Not till recently, the dynamic nature of cortical granules is appreciated and understood. The latest studies of mammalian cortical granules document that this organelle is not only biochemically heterogeneous, but also displays complex distribution during oocyte development. Interestingly, some cortical granules undergo exocytosis prior to fertilization; and a number of granule components function beyond the time of fertilization in regulating embryonic cleavage and preimplantation development, demonstrating their functional significance in fertilization as well as early embryonic development. The following review will present studies that investigate the biology of cortical granules and will also discuss new findings that uncover the dynamic aspect of this organelle in mammals.

  19. Increased Cortical Thickness in Professional On-Line Gamers

    Science.gov (United States)

    Hyun, Gi Jung; Shin, Yong Wook; Kim, Bung-Nyun; Cheong, Jae Hoon; Jin, Seong Nam

    2013-01-01

    Objective The bulk of recent studies have tested whether video games change the brain in terms of activity and cortical volume. However, such studies are limited by several factors including cross-sectional comparisons, co-morbidity, and short-term follow-up periods. In the present study, we hypothesized that cognitive flexibility and the volume of brain cortex would be correlated with the career length of on-line pro-gamers. Methods High-resolution magnetic resonance scans were acquired in twenty-three pro-gamers recruited from StarCraft pro-game teams. We measured cortical thickness in each individual using FreeSurfer and the cortical thickness was correlated with the career length and the performance of the pro-gamers. Results Career length was positively correlated with cortical thickness in three brain regions: right superior frontal gyrus, right superior parietal gyrus, and right precentral gyrus. Additionally, increased cortical thickness in the prefrontal cortex was correlated with winning rates of the pro-game league. Increased cortical thickness in the prefrontal and parietal cortices was also associated with higher performance of Wisconsin Card Sorting Test. Conclusion Our results suggest that in individuals without pathologic conditions, regular, long-term playing of on-line games is associated with volume changes in the prefrontal and parietal cortices, which are associated with cognitive flexibility. PMID:24474988

  20. The impact of occipital lobe cortical thickness on cognitive task performance: An investigation in Huntington's Disease.

    Science.gov (United States)

    Johnson, Eileanoir B; Rees, Elin M; Labuschagne, Izelle; Durr, Alexandra; Leavitt, Blair R; Roos, Raymund A C; Reilmann, Ralf; Johnson, Hans; Hobbs, Nicola Z; Langbehn, Douglas R; Stout, Julie C; Tabrizi, Sarah J; Scahill, Rachael I

    2015-12-01

    The occipital lobe is an important visual processing region of the brain. Following consistent findings of early neural changes in the occipital lobe in Huntington's Disease (HD), we examined cortical thickness across four occipital regions in premanifest (preHD) and early HD groups compared with controls. Associations between cortical thickness in gene positive individuals and performance on six cognitive tasks, each with a visual component, were examined. In addition, the association between cortical thickness in gene positive participants and one non-visual motor task was also examined for comparison. Cortical thickness was determined using FreeSurfer on T1-weighted 3T MR datasets from controls (N=97), preHD (N=109) and HD (N=69) from the TRACK-HD study. Regression models were fitted to assess between-group differences in cortical thickness, and relationships between performance on the cognitive tasks, the motor task and occipital thickness were examined in a subset of gene-positive participants (N=141). Thickness of the occipital cortex in preHD and early HD participants was reduced compared with controls. Regionally-specific associations between reduced cortical thickness and poorer performance were found for five of the six cognitive tasks, with the strongest associations in lateral occipital and lingual regions. No associations were found with the cuneus. The non-visual motor task was not associated with thickness of any region. The heterogeneous pattern of associations found in the present study suggests that occipital thickness negatively impacts cognition, but only in regions that are linked to relatively advanced visual processing (e.g., lateral occipital, lingual regions), rather than in basic visual processing regions such as the cuneus. Our results show, for the first time, the functional implications of occipital atrophy highlighted in recent studies in HD. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. The Computational Properties of a Simplified Cortical Column Model.

    Science.gov (United States)

    Cain, Nicholas; Iyer, Ramakrishnan; Koch, Christof; Mihalas, Stefan

    2016-09-01

    The mammalian neocortex has a repetitious, laminar structure and performs functions integral to higher cognitive processes, including sensory perception, memory, and coordinated motor output. What computations does this circuitry subserve that link these unique structural elements to their function? Potjans and Diesmann (2014) parameterized a four-layer, two cell type (i.e. excitatory and inhibitory) model of a cortical column with homogeneous populations and cell type dependent connection probabilities. We implement a version of their model using a displacement integro-partial differential equation (DiPDE) population density model. This approach, exact in the limit of large homogeneous populations, provides a fast numerical method to solve equations describing the full probability density distribution of neuronal membrane potentials. It lends itself to quickly analyzing the mean response properties of population-scale firing rate dynamics. We use this strategy to examine the input-output relationship of the Potjans and Diesmann cortical column model to understand its computational properties. When inputs are constrained to jointly and equally target excitatory and inhibitory neurons, we find a large linear regime where the effect of a multi-layer input signal can be reduced to a linear combination of component signals. One of these, a simple subtractive operation, can act as an error signal passed between hierarchical processing stages.

  2. Cell-specific gain modulation by synaptically released zinc in cortical circuits of audition.

    Science.gov (United States)

    Anderson, Charles T; Kumar, Manoj; Xiong, Shanshan; Tzounopoulos, Thanos

    2017-09-09

    In many excitatory synapses, mobile zinc is found within glutamatergic vesicles and is coreleased with glutamate. Ex vivo studies established that synaptically released (synaptic) zinc inhibits excitatory neurotransmission at lower frequencies of synaptic activity but enhances steady state synaptic responses during higher frequencies of activity. However, it remains unknown how synaptic zinc affects neuronal processing in vivo. Here, we imaged the sound-evoked neuronal activity of the primary auditory cortex in awake mice. We discovered that synaptic zinc enhanced the gain of sound-evoked responses in CaMKII-expressing principal neurons, but it reduced the gain of parvalbumin- and somatostatin-expressing interneurons. This modulation was sound intensity-dependent and, in part, NMDA receptor-independent. By establishing a previously unknown link between synaptic zinc and gain control of auditory cortical processing, our findings advance understanding about cortical synaptic mechanisms and create a new framework for approaching and interpreting the role of the auditory cortex in sound processing.

  3. Direct cortical hemodynamic mapping of somatotopy of pig nostril sensation by functional near-infrared cortical imaging (fNCI).

    Science.gov (United States)

    Uga, Minako; Saito, Toshiyuki; Sano, Toshifumi; Yokota, Hidenori; Oguro, Keiji; Rizki, Edmi Edison; Mizutani, Tsutomu; Katura, Takusige; Dan, Ippeita; Watanabe, Eiju

    2014-05-01

    Functional near-infrared spectroscopy (fNIRS) is a neuroimaging technique for the noninvasive monitoring of human brain activation states utilizing the coupling between neural activity and regional cerebral hemodynamics. Illuminators and detectors, together constituting optodes, are placed on the scalp, but due to the presence of head tissues, an inter-optode distance of more than 2.5cm is necessary to detect cortical signals. Although direct cortical monitoring with fNIRS has been pursued, a high-resolution visualization of hemodynamic changes associated with sensory, motor and cognitive neural responses directly from the cortical surface has yet to be realized. To acquire robust information on the hemodynamics of the cortex, devoid of signal complications in transcranial measurement, we devised a functional near-infrared cortical imaging (fNCI) technique. Here we demonstrate the first direct functional measurement of temporal and spatial patterns of cortical hemodynamics using the fNCI technique. For fNCI, inter-optode distance was set at 5mm, and light leakage from illuminators was prevented by a special optode holder made of a light-shielding rubber sheet. fNCI successfully detected the somatotopy of pig nostril sensation, as assessed in comparison with concurrent and sequential somatosensory-evoked potential (SEP) measurements on the same stimulation sites. Accordingly, the fNCI system realized a direct cortical hemodynamic measurement with a spatial resolution comparable to that of SEP mapping on the rostral region of the pig brain. This study provides an important initial step toward realizing functional cortical hemodynamic monitoring during neurosurgery of human brains. Copyright © 2014. Published by Elsevier Inc.

  4. Genome-Wide Search Identifies 1.9 Mb from the Polar Bear Y Chromosome for Evolutionary Analyses

    Science.gov (United States)

    Bidon, Tobias; Schreck, Nancy; Hailer, Frank; Nilsson, Maria A.; Janke, Axel

    2015-01-01

    The male-inherited Y chromosome is the major haploid fraction of the mammalian genome, rendering Y-linked sequences an indispensable resource for evolutionary research. However, despite recent large-scale genome sequencing approaches, only a handful of Y chromosome sequences have been characterized to date, mainly in model organisms. Using polar bear (Ursus maritimus) genomes, we compare two different in silico approaches to identify Y-linked sequences: 1) Similarity to known Y-linked genes and 2) difference in the average read depth of autosomal versus sex chromosomal scaffolds. Specifically, we mapped available genomic sequencing short reads from a male and a female polar bear against the reference genome and identify 112 Y-chromosomal scaffolds with a combined length of 1.9 Mb. We verified the in silico findings for the longer polar bear scaffolds by male-specific in vitro amplification, demonstrating the reliability of the average read depth approach. The obtained Y chromosome sequences contain protein-coding sequences, single nucleotide polymorphisms, microsatellites, and transposable elements that are useful for evolutionary studies. A high-resolution phylogeny of the polar bear patriline shows two highly divergent Y chromosome lineages, obtained from analysis of the identified Y scaffolds in 12 previously published male polar bear genomes. Moreover, we find evidence of gene conversion among ZFX and ZFY sequences in the giant panda lineage and in the ancestor of ursine and tremarctine bears. Thus, the identification of Y-linked scaffold sequences from unordered genome sequences yields valuable data to infer phylogenomic and population-genomic patterns in bears. PMID:26019166

  5. Discretization of 3d gravity in different polarizations

    Science.gov (United States)

    Dupuis, Maïté; Freidel, Laurent; Girelli, Florian

    2017-10-01

    We study the discretization of three-dimensional gravity with Λ =0 following the loop quantum gravity framework. In the process, we realize that different choices of polarization are possible. This allows us to introduce a new discretization based on the triad as opposed to the connection as in the standard loop quantum gravity framework. We also identify the classical nontrivial symmetries of discrete gravity, namely the Drinfeld double, given in terms of momentum maps. Another choice of polarization is given by the Chern-Simons formulation of gravity. Our framework also provides a new discretization scheme of Chern-Simons, which keeps track of the link between the continuum variables and the discrete ones. We show how the Poisson bracket we recover between the Chern-Simons holonomies allows us to recover the Goldman bracket. There is also a transparent link between the discrete Chern-Simons formulation and the discretization of gravity based on the connection (loop gravity) or triad variables (dual loop gravity).

  6. Polarization measurement for internal polarized gaseous targets

    International Nuclear Information System (INIS)

    Ye Zhenyu; Ye Yunxiu; Lv Haijiang; Mao Yajun

    2004-01-01

    The authors present an introduction to internal polarized gaseous targets, polarization method, polarization measurement method and procedure. To get the total nuclear polarization of hydrogen atoms (including the polarization of the recombined hydrogen molecules) in the target cell, authors have measured the parameters relating to atomic polarization and polarized hydrogen atoms and molecules. The total polarization of the target during our measurement is P T =0.853 ± 0.036. (authors)

  7. Disruption of the Cdc42/Par6/aPKC or Dlg/Scrib/Lgl Polarity Complex Promotes Epithelial Proliferation via Overlapping Mechanisms.

    Science.gov (United States)

    Schimizzi, Gregory V; Maher, Meghan T; Loza, Andrew J; Longmore, Gregory D

    2016-01-01

    The establishment and maintenance of apical-basal polarity is a defining characteristic and essential feature of functioning epithelia. Apical-basal polarity (ABP) proteins are also tumor suppressors that are targeted for disruption by oncogenic viruses and are commonly mutated in human carcinomas. Disruption of these ABP proteins is an early event in cancer development that results in increased proliferation and epithelial disorganization through means not fully characterized. Using the proliferating Drosophila melanogaster wing disc epithelium, we demonstrate that disruption of the junctional vs. basal polarity complexes results in increased epithelial proliferation via distinct downstream signaling pathways. Disruption of the basal polarity complex results in JNK-dependent proliferation, while disruption of the junctional complex primarily results in p38-dependent proliferation. Surprisingly, the Rho-Rok-Myosin contractility apparatus appears to play opposite roles in the regulation of the proliferative phenotype based on which polarity complex is disrupted. In contrast, non-autonomous Tumor Necrosis Factor (TNF) signaling appears to suppress the proliferation that results from apical-basal polarity disruption, regardless of which complex is disrupted. Finally we demonstrate that disruption of the junctional polarity complex activates JNK via the Rho-Rok-Myosin contractility apparatus independent of the cortical actin regulator, Moesin.

  8. Cerebellar cortical infarct cavities and vertebral artery disease

    Energy Technology Data Exchange (ETDEWEB)

    Cocker, Laurens J.L. de [University Medical Center Utrecht, Department of Radiology, Utrecht (Netherlands); Kliniek Sint-Jan Radiologie, Brussels (Belgium); Compter, A.; Kappelle, L.J.; Worp, H.B. van der [University Medical Center Utrecht, Department of Neurology and Neurosurgery, Brain Center Rudolf Magnus, Utrecht (Netherlands); Luijten, P.R.; Hendrikse, J. [University Medical Center Utrecht, Department of Radiology, Utrecht (Netherlands)

    2016-09-15

    Cerebellar cortical infarct cavities are a newly recognised entity associated with atherothromboembolic cerebrovascular disease and worse physical functioning. We aimed to investigate the relationship of cerebellar cortical infarct cavities with symptomatic vertebrobasilar ischaemia and with vascular risk factors. We evaluated the MR images of 46 patients with a recent vertebrobasilar TIA or stroke and a symptomatic vertebral artery stenosis ≥50 % from the Vertebral Artery Stenting Trial (VAST) for the presence of cerebellar cortical infarct cavities ≤1.5 cm. At inclusion in VAST, data were obtained on age, sex, history of vertebrobasilar TIA or stroke, and vascular risk factors. Adjusted risk ratios were calculated with Poisson regression analyses for the relation between cerebellar cortical infarct cavities and vascular risk factors. Sixteen out of 46 (35 %) patients showed cerebellar cortical infarct cavities on the initial MRI, and only one of these 16 patients was known with a previous vertebrobasilar TIA or stroke. In patients with symptomatic vertebrobasilar ischaemia, risk factor profiles of patients with cerebellar cortical infarct cavities were not different from patients without these cavities. Cerebellar cortical infarct cavities are seen on MRI in as much as one third of patients with recently symptomatic vertebral artery stenosis. Since patients usually have no prior history of vertebrobasilar TIA or stroke, cerebellar cortical infarct cavities should be added to the spectrum of common incidental brain infarcts visible on routine MRI. (orig.)

  9. Association of In Vivo [18F]AV-1451 Tau PET Imaging Results With Cortical Atrophy and Symptoms in Typical and Atypical Alzheimer Disease.

    Science.gov (United States)

    Xia, Chenjie; Makaretz, Sara J; Caso, Christina; McGinnis, Scott; Gomperts, Stephen N; Sepulcre, Jorge; Gomez-Isla, Teresa; Hyman, Bradley T; Schultz, Aaron; Vasdev, Neil; Johnson, Keith A; Dickerson, Bradford C

    2017-04-01

    Previous postmortem studies have long demonstrated that neurofibrillary tangles made of hyperphosphorylated tau proteins are closely associated with Alzheimer disease clinical phenotype and neurodegeneration pattern. Validating these associations in vivo will lead to new diagnostic tools for Alzheimer disease and better understanding of its neurobiology. To examine whether topographical distribution and severity of hyperphosphorylated tau pathologic findings measured by fluorine 18-labeled AV-1451 ([18F]AV-1451) positron emission tomographic (PET) imaging are linked with clinical phenotype and cortical atrophy in patients with Alzheimer disease. This observational case series, conducted from July 1, 2012, to July 30, 2015, in an outpatient referral center for patients with neurodegenerative diseases, included 6 patients: 3 with typical amnesic Alzheimer disease and 3 with atypical variants (posterior cortical atrophy, logopenic variant primary progressive aphasia, and corticobasal syndrome). Patients underwent [18F]AV-1451 PET imaging to measure tau burden, carbon 11-labeled Pittsburgh Compound B ([11C]PiB) PET imaging to measure amyloid burden, and structural magnetic resonance imaging to measure cortical thickness. Seventy-seven age-matched controls with normal cognitive function also underwent structural magnetic resonance imaging but not tau or amyloid PET imaging. Tau burden, amyloid burden, and cortical thickness. In all 6 patients (3 women and 3 men; mean age 61.8 years), the underlying clinical phenotype was associated with the regional distribution of the [18F]AV-1451 signal. Furthermore, within 68 cortical regions of interest measured from each patient, the magnitude of cortical atrophy was strongly correlated with the magnitude of [18F]AV-1451 binding (3 patients with amnesic Alzheimer disease, r = -0.82; P localizing and quantifying hyperphosphorylated tau in vivo, results of tau PET imaging will likely serve as a key biomarker that links a

  10. SKA2 Methylation is associated with Decreased Prefrontal Cortical Thickness and Greater PTSD Severity among Trauma-Exposed Veterans

    Science.gov (United States)

    Sadeh, Naomi; Spielberg, Jeffrey M.; Logue, Mark W.; Wolf, Erika J.; Smith, Alicia K.; Lusk, Joanna; Hayes, Jasmeet P.; Sperbeck, Emily; Milberg, William P.; McGlinchey, Regina E.; Salat, David H.; Carter, Weleetka C.; Stone, Annjanette; Schichman, Steven A.; Humphries, Donald E.; Miller, Mark W.

    2015-01-01

    Methylation of the SKA2 gene has recently been identified as a promising biomarker of suicide risk. Based on this finding, we examined associations between SKA2 methylation, cortical thickness, and psychiatric phenotypes linked to suicide in trauma-exposed veterans. 200 trauma-exposed white non-Hispanic veterans of the recent conflicts in Iraq and Afghanistan (91% male) underwent clinical assessment and had blood drawn for genotyping and methylation analysis. 145 participants also had neuroimaging data available. Based on previous research, we examined DNA methylation at the CpG locus cg13989295 as well as DNA methylation adjusted for genotype at the methylation-associated SNP (rs7208505) in relationship to whole-brain cortical thickness, posttraumatic stress disorder symptoms (PTSD), and depression symptoms. Whole-brain vertex-wise analyses identified three clusters in prefrontal cortex that were associated with genotype-adjusted SKA2 DNA methylation (methylationadj). Specifically, DNA methylationadj was associated with bilateral reductions of cortical thickness in frontal pole and superior frontal gyrus, and similar effects were found in the right orbitofrontal cortex and right inferior frontal gyrus. PTSD symptom severity was positively correlated with SKA2 DNA methylationadj and negatively correlated with cortical thickness in these regions. Mediation analyses showed a significant indirect effect of PTSD on cortical thickness via SKA2 methylation status. Results suggest that DNA methylationadj of SKA2 in blood indexes stress-related psychiatric phenotypes and neurobiology, pointing to its potential value as a biomarker of stress exposure and susceptibility. PMID:26324104

  11. Perceived Occupational Stress is associated with Decreased Cortical Activity of the Prefrontal Cortex: A Multichannel Near-infrared Spectroscopy Study.

    Science.gov (United States)

    Chou, Po-Han; Lin, Wei-Hao; Hung, Chao-An; Chang, Chiung-Chih; Li, Wan-Rung; Lan, Tsuo-Hung; Huang, Min-Wei

    2016-12-13

    Despite an increasing number of reports on the associations between chronic occupational stress and structural and functional changes of the brain, the underlying neural correlates of perceived occupational stress is still not clear. Perceived stress reflects the extents to which situations are appraised as stressful at a given point in one's life. Using near-infrared spectroscopy, we investigated the associations between perceived occupational stress and cortical activity over the bilateral frontotemporal regions during a verbal fluency test. Sixty-eight participants (17 men, 51 women), 20-62 years of age were recruited. Perceived occupational stress was measured using the Chinese version of Job Content Questionnaire, and the Chinese version of the Copenhagen Burnout Inventory. We found statistically significant negative associations between occupational burnout and brain cortical activity over the fronto-polar and dorsolateral prefrontal cortex during the VFT (r = -0.343 to -0.464). In conclusion, our research demonstrated a possible neural basis of perceived occupational stress that are distributed across the prefrontal cortex.

  12. Cortical thickness patterns as state biomarker of anorexia nervosa.

    Science.gov (United States)

    Lavagnino, Luca; Mwangi, Benson; Cao, Bo; Shott, Megan E; Soares, Jair C; Frank, Guido K W

    2018-03-01

    Only few studies have investigated cortical thickness in anorexia nervosa (AN), and it is unclear whether patterns of altered cortical thickness can be identified as biomarkers for AN. Cortical thickness was measured in 19 adult women with restricting-type AN, 24 individuals recovered from restricting-type AN (REC-AN) and 24 healthy controls. Those individuals with current or recovered from AN had previously shown altered regional cortical volumes across orbitofrontal cortex and insula. A linear relevance vector machine-learning algorithm estimated patterns of regional thickness across 24 subdivisions of those regions. Region-based analysis showed higher cortical thickness in AN and REC-AN, compared to controls, in the right medial orbital (olfactory) sulcus, and greater cortical thickness for short insular gyri in REC-AN versus controls bilaterally. The machine-learning algorithm identified a pattern of relatively higher right orbital, right insular and left middle frontal cortical thickness, but lower left orbital, right middle and inferior frontal, and bilateral superior frontal cortical thickness specific to AN versus controls (74% specificity and 74% sensitivity, χ 2 p < .004); predicted probabilities differed significantly between AN and controls (p < .023). No pattern significantly distinguished the REC-AN group from controls. Higher cortical thickness in medial orbitofrontal cortex and insula probably contributes to higher gray matter volume in AN in those regions. The machine-learning algorithm identified a mixed pattern of mostly higher orbital and insular, but relatively lower superior frontal cortical thickness in individuals with current AN. These novel results suggest that regional cortical thickness patterns could be state markers for AN. © 2018 Wiley Periodicals, Inc.

  13. Slow-oscillatory transcranial direct current stimulation can induce bidirectional shifts in motor cortical excitability in awake humans

    DEFF Research Database (Denmark)

    Groppa, S; Bergmann, T O; Siems, C

    2010-01-01

    Constant transcranial direct stimulation (c-tDCS) of the primary motor hand area (M1(HAND)) can induce bidirectional shifts in motor cortical excitability depending on the polarity of tDCS. Recently, anodal slow oscillation stimulation at a frequency of 0.75 Hz has been shown to augment intrinsic...... slow oscillations during sleep and theta oscillations during wakefulness. To embed this new type of stimulation into the existing tDCS literature, we aimed to characterize the after effects of slowly oscillating stimulation (so-tDCS) on M1(HAND) excitability and to compare them to those of c-tDCS. Here...

  14. Do not resonate with actions: sentence polarity modulates cortico-spinal excitability during action-related sentence reading.

    Directory of Open Access Journals (Sweden)

    Marco Tullio Liuzza

    Full Text Available BACKGROUND: Theories of embodied language suggest that the motor system is differentially called into action when processing motor-related versus abstract content words or sentences. It has been recently shown that processing negative polarity action-related sentences modulates neural activity of premotor and motor cortices. METHODS AND FINDINGS: We sought to determine whether reading negative polarity sentences brought about differential modulation of cortico-spinal motor excitability depending on processing hand-action related or abstract sentences. Facilitatory paired-pulses Transcranial Magnetic Stimulation (pp-TMS was applied to the primary motor representation of the right-hand and the recorded amplitude of induced motor-evoked potentials (MEP was used to index M1 activity during passive reading of either hand-action related or abstract content sentences presented in both negative and affirmative polarity. Results showed that the cortico-spinal excitability was affected by sentence polarity only in the hand-action related condition. Indeed, in keeping with previous TMS studies, reading positive polarity, hand action-related sentences suppressed cortico-spinal reactivity. This effect was absent when reading hand action-related negative polarity sentences. Moreover, no modulation of cortico-spinal reactivity was associated with either negative or positive polarity abstract sentences. CONCLUSIONS: Our results indicate that grammatical cues prompting motor negation reduce the cortico-spinal suppression associated with affirmative action sentences reading and thus suggest that motor simulative processes underlying the embodiment may involve even syntactic features of language.

  15. Retrieving the polarization information for satellite-to-ground light communication

    International Nuclear Information System (INIS)

    Tao, Qiangqiang; Guo, Zhongyi; Xu, Qiang; Gao, Jun; Jiao, Weiyan; Wang, Xinshun; Qu, Shiliang

    2015-01-01

    In this paper, we have investigated the reconstruction of the polarization states (degree of polarization (DoP) and angle of polarization (AoP)) of the incident light which passed through a 10 km atmospheric medium between the satellite and the Earth. Here, we proposed a more practical atmospheric model in which the 10 km atmospheric medium is divided into ten layers to be appropriate for the Monte Carlo simulation algorithm. Based on this model, the polarization retrieve (PR) method can be used for reconstructing the initial polarization information effectively, and the simulated results demonstrate that the mean errors of the retrieved DoP and AoP are very close to zero. Moreover, the results also show that although the atmospheric medium system is fixed, the Mueller matrices for the downlink and uplink are completely different, which shows that the light transmissions in the two links are irreversible in the layered atmospheric medium system. (paper)

  16. Modeling neurodevelopment and cortical dysfunction in SPG11-linked hereditary spastic paraplegia using human induced pluripotent stem cells

    OpenAIRE

    Mishra, Himanshu Kumar

    2016-01-01

    Hereditary spastic paraplegias (HSPs) are a heterogeneous group of inherited motor neuron diseases characterized by progressive spasticity and weakness of the lower limbs. Mutations in the Spastic Paraplegia Gene11 (SPG11), encoding spatacsin, cause the most frequent form of autosomal recessive HSP. SPG11 patients are clinically distinguishable from most other HSPs, by severe cortical atrophy and presence of a thin corpus callosum (TCC), associated with cognitive deficits. Partly due to l...

  17. Loss of Function Studies in Mice and Genetic Association Link Receptor Protein Tyrosine Phosphatase a to Schizophrenia

    DEFF Research Database (Denmark)

    Takahashi, Nagahide; Nielsen, Karin Sandager; Aleksic, Branko

    2011-01-01

    Solid evidence links schizophrenia (SZ) susceptibility to neurodevelopmental processes involving tyrosine phosphorylation-mediated signaling. Mouse studies implicate the Ptpra gene, encoding protein tyrosine phosphatase RPTPa, in the control of radial neuronal migration, cortical cytoarchitecture...

  18. Widespread cortical thinning in patients with neuromyelitis optica spectrum disorder.

    Science.gov (United States)

    Kim, S-H; Kwak, K; Hyun, J-W; Jeong, I H; Jo, H-J; Joung, A; Kim, J-H; Lee, S H; Yun, S; Joo, J; Lee, J-M; Kim, H J

    2016-07-01

    Studies on cortical involvement and its relationship with cognitive function in patients with neuromyelitis optica spectrum disorder (NMOSD) remain scarce. The objective of this study was to compare cortical thickness on magnetic resonance imaging (MRI) between patients with NMOSD and multiple sclerosis (MS) and to investigate its relationship with clinical features and cognitive function. This observational clinical imaging study of 91 patients with NMOSD, 52 patients with MS and 44 healthy controls was conducted from 1 December 2013 to 30 April 2015 at the institutional referral center. Three tesla MRI of the brain and neuropsychological tests were performed. Cortical thickness was measured using three-dimensional surface-based analysis. Both sets of patients exhibited cortical thinning throughout the entire brain cortex. Patients with MS showed a significantly greater reduction in cortical thickness over broad regions of the bilateral frontal and parieto-temporal cortices and the left precuneus compared to those with NMOSD. Memory functions in patients with MS were correlated with broad regional cortical thinning, whereas no significant associations were observed between cortical thickness and cognitive function in patients with NMOSD. Widespread cortical thinning was observed in patients with NMOSD and MS, but the extent of cortical thinning was greater in patients with MS. The more severe cortical atrophy may contribute to memory impairment in patients with MS but not in those with NMOSD. These results provide in vivo evidence that the severity and clinical relevance of cortical thinning differ between NMOSD and MS. © 2016 EAN.

  19. The Diversity of Cortical Inhibitory Synapses

    Directory of Open Access Journals (Sweden)

    Yoshiyuki eKubota

    2016-04-01

    Full Text Available The most typical and well known inhibitory action in the cortical microcircuit is a strong inhibition on the target neuron by axo-somatic synapses. However, it has become clear that synaptic inhibition in the cortex is much more diverse and complicated. Firstly, at least ten or more inhibitory non-pyramidal cell subtypes engage in diverse inhibitory functions to produce the elaborate activity characteristic of the different cortical states. Each distinct non-pyramidal cell subtype has its own independent inhibitory function. Secondly, the inhibitory synapses innervate different neuronal domains, such as axons, spines, dendrites and soma, and their IPSP size is not uniform. Thus cortical inhibition is highly complex, with a wide variety of anatomical and physiological modes. Moreover, the functional significance of the various inhibitory synapse innervation styles and their unique structural dynamic behaviors differ from those of excitatory synapses. In this review, we summarize our current understanding of the inhibitory mechanisms of the cortical microcircuit.

  20. Cortical Plasticity Induction by Pairing Subthalamic Nucleus Deep-Brain Stimulation and Primary Motor Cortical Transcranial Magnetic Stimulation in Parkinson's Disease.

    Science.gov (United States)

    Udupa, Kaviraja; Bahl, Nina; Ni, Zhen; Gunraj, Carolyn; Mazzella, Filomena; Moro, Elena; Hodaie, Mojgan; Lozano, Andres M; Lang, Anthony E; Chen, Robert

    2016-01-13

    Noninvasive brain stimulation studies have shown abnormal motor cortical plasticity in Parkinson's disease (PD). These studies used peripheral nerve stimulation paired with transcranial magnetic stimulation (TMS) to primary motor cortex (M1) at specific intervals to induce plasticity. Induction of cortical plasticity through stimulation of the basal ganglia (BG)-M1 connections has not been studied. In the present study, we used a novel technique of plasticity induction by repeated pairing of deep-brain stimulation (DBS) of the BG with M1 stimulation using TMS. We hypothesize that repeated pairing of subthalamic nucleus (STN)-DBS and M1-TMS at specific time intervals will lead to plasticity in the M1. Ten PD human patients with STN-DBS were studied in the on-medication state with DBS set to 3 Hz. The interstimulus intervals (ISIs) between STN-DBS and TMS that produced cortical facilitation were determined individually for each patient. Three plasticity induction conditions with repeated pairings (180 times) at specific ISIs (∼ 3 and ∼ 23 ms) that produced cortical facilitation and a control ISI of 167 ms were tested in random order. Repeated pairing of STN-DBS and M1-TMS at short (∼ 3 ms) and medium (∼ 23 ms) latencies increased M1 excitability that lasted for at least 45 min, whereas the control condition (fixed ISI of 167 ms) had no effect. There were no specific changes in motor thresholds, intracortical circuits, or recruitment curves. Our results indicate that paired-associative cortical plasticity can be induced by repeated STN and M1 stimulation at specific intervals. These results show that STN-DBS can modulate cortical plasticity. We introduced a new experimental paradigm to test the hypothesis that pairing subthalamic nucleus deep-brain stimulation (STN-DBS) with motor cortical transcranial magnetic stimulation (M1-TMS) at specific times can induce cortical plasticity in patients with Parkinson's disease (PD). We found that repeated pairing of STN

  1. Dynamics of Ionic Shifts in Cortical Spreading Depression.

    Science.gov (United States)

    Enger, Rune; Tang, Wannan; Vindedal, Gry Fluge; Jensen, Vidar; Johannes Helm, P; Sprengel, Rolf; Looger, Loren L; Nagelhus, Erlend A

    2015-11-01

    Cortical spreading depression is a slowly propagating wave of near-complete depolarization of brain cells followed by temporary suppression of neuronal activity. Accumulating evidence indicates that cortical spreading depression underlies the migraine aura and that similar waves promote tissue damage in stroke, trauma, and hemorrhage. Cortical spreading depression is characterized by neuronal swelling, profound elevation of extracellular potassium and glutamate, multiphasic blood flow changes, and drop in tissue oxygen tension. The slow speed of the cortical spreading depression wave implies that it is mediated by diffusion of a chemical substance, yet the identity of this substance and the pathway it follows are unknown. Intercellular spread between gap junction-coupled neurons or glial cells and interstitial diffusion of K(+) or glutamate have been proposed. Here we use extracellular direct current potential recordings, K(+)-sensitive microelectrodes, and 2-photon imaging with ultrasensitive Ca(2+) and glutamate fluorescent probes to elucidate the spatiotemporal dynamics of ionic shifts associated with the propagation of cortical spreading depression in the visual cortex of adult living mice. Our data argue against intercellular spread of Ca(2+) carrying the cortical spreading depression wavefront and are in favor of interstitial K(+) diffusion, rather than glutamate diffusion, as the leading event in cortical spreading depression. © The Author 2015. Published by Oxford University Press.

  2. Axi-symmetric patterns of active polar filaments on spherical and composite surfaces

    Science.gov (United States)

    Srivastava, Pragya; Rao, Madan

    2014-03-01

    Experiments performed on Fission Yeast cells of cylindrical and spherical shapes, rod-shaped bacteria and reconstituted cylindrical liposomes suggest the influence of cell geometry on patterning of cortical actin. A theoretical model based on active hydrodynamic description of cortical actin that includes curvature-orientation coupling predicts spontaneous formation of acto-myosin rings, cables and nodes on cylindrical and spherical geometries [P. Srivastava et al, PRL 110, 168104(2013)]. Stability and dynamics of these patterns is also affected by the cellular shape and has been observed in experiments performed on Fission Yeast cells of spherical shape. Motivated by this, we study the stability and dynamics of axi-symmetric patterns of active polar filaments on the surfaces of spherical, saddle shaped and conical geometry and classify the stable steady state patterns on these surfaces. Based on the analysis of the fluorescence images of Myosin-II during ring slippage we propose a simple mechanical model for ring-sliding based on force balance and make quantitative comparison with the experiments performed on Fission Yeast cells. NSF Grant DMR-1004789 and Syracuse Soft Matter Program.

  3. Catarata polar anterior piramidal deslocada para a câmara anterior causando edema de córnea: relato de caso Corneal edema caused by a pyramidal anterior polar cataract dislocated to the anterior chamber: case report

    Directory of Open Access Journals (Sweden)

    Ramon Coral Ghanem

    2004-08-01

    Full Text Available Cataratas polares anteriores piramidais são opacidades cônicas que se projetam para a câmara anterior a partir da cápsula anterior do cristalino. Na grande maioria dos pacientes a opacidade permanece aderida e estável durante toda a vida. O objetivo deste trabalho é documentar uma manifestação incomum desse tipo de catarata: a deiscência espontânea das pirâmides para a câmara anterior causando descompensação endotelial e edema corneal bilateral. Relatamos o caso de uma paciente feminina, de 66 anos, branca, que apresentava edema corneal localizado inferiormente no olho direito associado à lesão nodular branco-esclerótica compatível com a pirâmide anterior da catarata polar. O olho esquerdo apresentava edema corneal difuso intenso e presença de uma catarata polar anterior com a região piramidal deslocada para a câmara anterior. Sabe-se que a pirâmide anterior pode permanecer inabsorvida na câmara anterior por longo período, pois é composta de tecido colágeno denso. Isto causa perda endotelial progressiva e edema corneal e deve ser considerada indicação de remoção cirúrgica da catarata polar anterior e de seu fragmento. Ressalta-se, também, a importância do bom senso no julgamento das cataratas polares anteriores, considerando-se tamanho da opacidade, simetria das opacidades e componente cortical associado, na tentativa de se evitar ambliopia.Pyramidal anterior polar cataracts are conical opacities that project into the anterior chamber from the anterior capsule of the lens. In the vast majority of patients the opacity remains bound and stable throughout life. We report an unusual complication of this type of cataract: spontaneous dehiscence of the pyramids to the anterior chamber causing bilateral endothelial damage and corneal edema. 66-year-old white woman presented with inferior corneal edema in the right eye and diffuse corneal edema in the left eye. A white nodular lesion was observed in the inferior angle

  4. Genome-Wide Search Identifies 1.9 Mb from the Polar Bear Y Chromosome for Evolutionary Analyses.

    Science.gov (United States)

    Bidon, Tobias; Schreck, Nancy; Hailer, Frank; Nilsson, Maria A; Janke, Axel

    2015-05-27

    The male-inherited Y chromosome is the major haploid fraction of the mammalian genome, rendering Y-linked sequences an indispensable resource for evolutionary research. However, despite recent large-scale genome sequencing approaches, only a handful of Y chromosome sequences have been characterized to date, mainly in model organisms. Using polar bear (Ursus maritimus) genomes, we compare two different in silico approaches to identify Y-linked sequences: 1) Similarity to known Y-linked genes and 2) difference in the average read depth of autosomal versus sex chromosomal scaffolds. Specifically, we mapped available genomic sequencing short reads from a male and a female polar bear against the reference genome and identify 112 Y-chromosomal scaffolds with a combined length of 1.9 Mb. We verified the in silico findings for the longer polar bear scaffolds by male-specific in vitro amplification, demonstrating the reliability of the average read depth approach. The obtained Y chromosome sequences contain protein-coding sequences, single nucleotide polymorphisms, microsatellites, and transposable elements that are useful for evolutionary studies. A high-resolution phylogeny of the polar bear patriline shows two highly divergent Y chromosome lineages, obtained from analysis of the identified Y scaffolds in 12 previously published male polar bear genomes. Moreover, we find evidence of gene conversion among ZFX and ZFY sequences in the giant panda lineage and in the ancestor of ursine and tremarctine bears. Thus, the identification of Y-linked scaffold sequences from unordered genome sequences yields valuable data to infer phylogenomic and population-genomic patterns in bears. © The Author(s) 2015. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  5. Age Effects on Cortical Thickness in Cognitively Normal Elderly Individuals

    Directory of Open Access Journals (Sweden)

    Sona Hurtz

    2014-07-01

    Full Text Available Background/Aims: Atrophy in both grey and white matter is found in normal aging. The prefrontal cortex and the frontal lobe white matter are thought to be the most affected regions. Our aim was to examine the effects of normal aging on cortical grey matter using a 3D quantitative cortical mapping method. Methods: We analyzed 1.5-tesla brain magnetic resonance imaging data from 44 cognitively normal elderly subjects using cortical pattern matching and cortical thickness analyses. Linear regression analysis was used to study the effect of age on cortical thickness. 3D map-wide correction for multiple comparisons was conducted with permutation analyses using a threshold of p Results: We found a significant negative association between age and cortical thickness in the right hemisphere (pcorrected = 0.009 and a trend level association in the left hemisphere (pcorrected = 0.081. Age-related changes were greatest in the sensorimotor, bilateral dorsal anterior cingulate and supplementary motor cortices, and the right posterior middle and inferior frontal gyri. Age effects greater in the medial than lateral visual association cortices were also seen bilaterally. Conclusion: Our novel method further validates that normal aging results in diffuse cortical thinning that is most pronounced in the frontal and visual association cortices.

  6. Doubling transmission capacity in optical wireless system by antenna horizontal- and vertical-polarization multiplexing.

    Science.gov (United States)

    Li, Xinying; Yu, Jianjun; Zhang, Junwen; Dong, Ze; Chi, Nan

    2013-06-15

    We experimentally demonstrate 2×56 Gb/s two-channel polarization-division-multiplexing quadrature-phase-shift-keying signal delivery over 80 km single-mode fiber-28 and 2 m Q-band (33-50 GHz) wireless link, adopting antenna horizontal- (H-) and vertical-polarization (V-polarization) multiplexing. At the wireless receiver, classic constant-modulus-algorithm equalization based on digital signal processing can realize polarization demultiplexing and remove the crosstalk at the same antenna polarization. By adopting antenna polarization multiplexing, the signal baud rate and performance requirements for optical and wireless devices can be reduced but at the cost of double antennas and devices, while wireless transmission capacity can also be increased but at the cost of stricter requirements for V-polarization. The isolation is only about 19 dB when V-polarization deviation approaches 10°, which will affect high-speed (>50 Gb/s) wireless delivery.

  7. Cortical changes in cerebral small vessel diseases: a 3D MRI study of cortical morphology in CADASIL

    International Nuclear Information System (INIS)

    Jouvent, E.; Bousser, M.G.; Chabriat, H.; Jouvent, E.; Bousser, M.G.; Chabriat, H.; Porcher, R.; Viswanathan, A.; Viswanathan, A.; Viswanathan, A.; O'Sullivan, M.; Dichgans, M.; Guichard, J.P.

    2008-01-01

    Brain atrophy represents a key marker of disease progression in cerebrovascular disorders. The 3D changes of cortex morphology occurring during the course of small vessel diseases of the brain (SVDB) remain poorly understood. The objective of this study was to assess the changes affecting depth and surface area of cortical sulci and their clinical and radiological correlates in a cohort of patients with cerebral autosomal dominant arteriolopathy with subcortical infarcts and leukoencephalopathy (CADASIL), a genetic SVDB. Data were obtained from a series of 69 CADASIL patients. Validated methods were used to determine depth and surface area of four cortical sulci. The ratio of brain to intracranial cavity volumes (brain parenchymal fraction-BPF), volume of lacunar lesions (LL) and of white matter hyper-intensities, number of cerebral micro-haemorrhages, and mean apparent diffusion coefficient were also measured. Association between depth and surface area of the cortical sulci and BPF, clinical status and subcortical MRI lesions were tested. Depth and surface area of cortical sulci obtained in 54 patients were strongly correlated with both cognitive score and disability scales. Depth was related to the extent of subcortical lesions, surface area was related only to age. In additional analyses, the depth of the cingular sulcus was independently associated with the volume of LL (P 0.001), and that of the superior frontal sulcus with the mean apparent diffusion coefficient (P 0.003). In CADASIL, important morphological changes of cortical sulci occur in association with clinical worsening,extension of subcortical tissue damage and progression of global cerebral atrophy. These results suggest that the examination of cortical morphology may be of high clinical relevance in SVDB. (authors)

  8. Prominent microglial activation in cortical white matter is selectively associated with cortical atrophy in primary progressive aphasia.

    Science.gov (United States)

    Ohm, Daniel T; Kim, Garam; Gefen, Tamar; Rademaker, Alfred; Weintraub, Sandra; Bigio, Eileen; Mesulam, M-Marsel; Rogalski, Emily; Geula, Changiz

    2018-04-21

    Primary progressive aphasia (PPA) is a clinical syndrome characterized by selective language impairments associated with focal cortical atrophy favouring the language dominant hemisphere. PPA is associated with Alzheimer's disease (AD), frontotemporal lobar degeneration (FTLD), and significant accumulation of activated microglia. Activated microglia can initiate an inflammatory cascade that may contribute to neurodegeneration, but their quantitative distribution in cortical white matter and their relationship with cortical atrophy are unknown. We investigated white matter activated microglia and their association with grey matter atrophy in 10 PPA cases with either AD or FTLD-TDP pathology. Activated microglia were quantified with optical density measures of HLA-DR immunoreactivity in two regions with peak cortical atrophy, and one non-atrophied region within the language dominant hemisphere of each PPA case. Non-atrophied contralateral homologues of the language dominant regions were examined for hemispheric asymmetry. Qualitatively, greater densities of activated microglia were observed in cortical white matter when compared to grey matter. Quantitative analyses revealed significantly greater densities of activated microglia in the white matter of atrophied regions compared to non-atrophied regions in the language dominant hemisphere (p<0.05). Atrophied regions of the language dominant hemisphere also showed significantly more activated microglia compared to contralateral homologues (p<0.05). White matter activated microglia accumulate more in atrophied regions in the language dominant hemisphere of PPA. While microglial activation may constitute a response to neurodegenerative processes in white matter, the resultant inflammatory processes may also exacerbate disease progression and contribute to cortical atrophy. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  9. Acute hepatic encephalopathy with diffuse cortical lesions

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, S.M.; Spreer, J.; Schumacher, M. [Section of Neuroradiology, Univ. of Freiburg (Germany); Els, T. [Dept. of Neurology, University of Freiburg (Germany)

    2001-07-01

    Acute hepatic encephalopathy is a poorly defined syndrome of heterogeneous aetiology. We report a 49-year-old woman with alcoholic cirrhosis and hereditary haemorrhagic telangiectasia who developed acute hepatic coma induced by severe gastrointestinal bleeding. Laboratory analysis revealed excessively elevated blood ammonia. MRI showed lesions compatible with chronic hepatic encephalopathy and widespread cortical signal change sparing the perirolandic and occipital cortex. The cortical lesions resembled those of hypoxic brain damage and were interpreted as acute toxic cortical laminar necrosis. (orig.)

  10. Acute hepatic encephalopathy with diffuse cortical lesions

    International Nuclear Information System (INIS)

    Arnold, S.M.; Spreer, J.; Schumacher, M.; Els, T.

    2001-01-01

    Acute hepatic encephalopathy is a poorly defined syndrome of heterogeneous aetiology. We report a 49-year-old woman with alcoholic cirrhosis and hereditary haemorrhagic telangiectasia who developed acute hepatic coma induced by severe gastrointestinal bleeding. Laboratory analysis revealed excessively elevated blood ammonia. MRI showed lesions compatible with chronic hepatic encephalopathy and widespread cortical signal change sparing the perirolandic and occipital cortex. The cortical lesions resembled those of hypoxic brain damage and were interpreted as acute toxic cortical laminar necrosis. (orig.)

  11. Post-adolescent developmental changes in cortical complexity.

    Science.gov (United States)

    Sandu, Anca-Larisa; Izard, Edouard; Specht, Karsten; Beneventi, Harald; Lundervold, Arvid; Ystad, Martin

    2014-11-27

    Post-adolescence is known to be a period of general maturation and development in the human brain. In brain imaging, volumetric and morphologic cortical grey-matter changes can easily be assessed, but the analysis of cortical complexity seems to have been broadly neglected for this age interval. Magnetic resonance imaging (MRI) was used to acquire structural brain images. The study involved 17 adolescents (mean age 14.1 ± 0.27, 11 girls) who were compared with 14 young adults (mean age 24.24 ± 2.76, 7 women) for measures of brain complexity (fractal dimension--FD), grey matter (GM) volume and surface-area of cortical ribbon. FD was calculated using box-counting and Minkowski-Bouligand methods; FD and GM volume were measured for the whole brain, each hemisphere and lobes: frontal, occipital, parietal and temporal. The results show that the adults have a lower cortical complexity than the adolescents, which was significant for whole brain, left and right hemisphere, frontal and parietal lobes for both genders; and only for males in left temporal lobe. The GM volume was smaller in men than in boys for almost all measurements, and smaller in women than in girls just for right parietal lobe. A significant Pearson correlation was found between FD and GM volume for whole brain and each hemisphere in both genders. The decrease of the GM surface-area was significant in post-adolescence for males, not for females. During post-adolescence there are common changes in cortical complexity in the same regions for both genders, but there are also gender specific changes in some cortical areas. The sex differences from different cortical measurements (FD, GM volume and surface-area of cortical ribbon) could suggest a maturation delay in specific brain regions for each gender in relation to the other and might be explained through the functional role of the corresponding regions reflected in gender difference of developed abilities.

  12. Cortical areas involved in Arabic number reading.

    Science.gov (United States)

    Roux, F-E; Lubrano, V; Lauwers-Cances, V; Giussani, C; Démonet, J-F

    2008-01-15

    Distinct functional pathways for processing words and numbers have been hypothesized from the observation of dissociated impairments of these categories in brain-damaged patients. We aimed to identify the cortical areas involved in Arabic number reading process in patients operated on for various brain lesions. Direct cortical electrostimulation was prospectively used in 60 brain mappings. We used object naming and two reading tasks: alphabetic script (sentences and number words) and Arabic number reading. Cortical areas involved in Arabic number reading were identified according to location, type of interference, and distinctness from areas associated with other language tasks. Arabic number reading was sustained by small cortical areas, often extremely well localized (area (Brodmann area 45), the anterior part of the dominant supramarginal gyrus (Brodmann area 40; p area (Brodmann area 37; p areas.

  13. Emerging Translational Variance: Vacuum Polarization Energy of the ϕ6 Kink

    Directory of Open Access Journals (Sweden)

    H. Weigel

    2017-01-01

    Full Text Available We propose an efficient method to compute the vacuum polarization energy of static field configurations that do not allow decomposition into symmetric and antisymmetric channels in one space dimension. In particular, we compute the vacuum polarization energy of the kink soliton in the ϕ6 model. We link the dependence of this energy on the position of the center of the soliton to the different masses of the quantum fluctuations at negative and positive spatial infinity.

  14. Prickle isoforms control the direction of tissue polarity by microtubule independent and dependent mechanisms

    Directory of Open Access Journals (Sweden)

    Katherine A. Sharp

    2016-03-01

    Full Text Available Planar cell polarity signaling directs the polarization of cells within the plane of many epithelia. While these tissues exhibit asymmetric localization of a set of core module proteins, in Drosophila, more than one mechanism links the direction of core module polarization to the tissue axes. One signaling system establishes a polarity bias in the parallel, apical microtubules upon which vesicles containing core proteins traffic. Swapping expression of the differentially expressed Prickle isoforms, Prickle and Spiny-legs, reverses the direction of core module polarization. Studies in the proximal wing and the anterior abdomen indicated that this results from their differential control of microtubule polarity. Prickle and Spiny-legs also control the direction of polarization in the distal wing (D-wing and the posterior abdomen (P-abd. We report here that this occurs without affecting microtubule polarity in these tissues. The direction of polarity in the D-wing is therefore likely determined by a novel mechanism independent of microtubule polarity. In the P-abd, Prickle and Spiny-legs interpret at least two directional cues through a microtubule-polarity-independent mechanism.

  15. Cortical and sub-cortical effects in primate models of cocaine use: implications for addiction and the increased risk of psychiatric illness.

    Science.gov (United States)

    Bradberry, Charles W

    2011-02-01

    Drug abuse is a serious risk factor for the incidence and severity of multiple psychiatric illnesses. Understanding the neurobiological consequences of repeated exposure to abused drugs can help to inform how those risks are manifested in terms of specific neurochemical mechanisms and brain networks. This review examines selective studies in non-human primates that employed a cocaine self-administration model. Neurochemical consequences of chronic exposure appear to differ from observations in rodent studies. Whereas chronic intermittent exposure in the rodent is usually associated with a dose-dependent increase in dopaminergic response to a cocaine challenge, in the rhesus monkey, high cumulative exposure was not observed to cause a sensitized dopamine response. These non-human primate observations are concordant with clinical findings in human users. The results of cue exposure studies on dopaminergic transmission are also reviewed. Direct microdialysis measurements indicate that there is not a sustained increase in dopamine associated with cocaine-linked cues. As an alternative to striatal dopaminergic mechanisms mediating cue effects, single unit studies in prefrontal cortex during self-administration in monkeys suggests the orbitofrontal and anterior cingulate cortex are strongly engaged by cocaine cues. Based on the strong clinical imaging literature on cortical and cognitive dysfunction associated with addiction, it is proposed that the strong engagement of cortical systems during repeated cocaine reinforcement results in maladaptive changes that contribute to the risks of drug use for exacerbation of other psychiatric disorders.

  16. Polar crane

    International Nuclear Information System (INIS)

    Makosinski, S.

    1981-01-01

    In many applications polar cranes have to be repeatedly positioned with high accuracy. A guidance system is disclosed which has two pairs of guides. Each guide consists of two rollers carried by a sheave rotatable mounted on the crane bridge, the rollers being locatable one on each side of a guideway, e.g. the circular track on which the bridge runs. The pairs of guides are interconnected by respective rope loops which pass around and are locked to the respective pairs of sheaves in such a manner that movement of one guide results in equal movement of the other guide in a sense to maintain the repeatability of positioning of the centre of the bridge. A hydraulically-linked guide system is also described. (author)

  17. Cortical enhancement in chronic subdural hematoma

    International Nuclear Information System (INIS)

    Taguchi, Yoshio; Sato, Jun; Makita, Tadatoshi; Hayashi, Shigetoshi; Nakamura, Norio.

    1981-01-01

    In the CT findings of chronic subdural hematoma, brain enhancement adjacent to a subdural hematoma was seen occasionally after the injection of a contrast material. The authors called this finding ''cortical enhancement'', and 35 cases of chronic subdural hematoma were studied concerning cortical enhancement in relation to age, clinical signs and symptoms, hematoma density, and volume of the hematoma. Eight cases out of the 35 were subjected to measurements of the regional cerebral blood flow preoperatively by the method of the carotid injection of Xe-133. Cortical enhancement was apt to be seen in the cases which revealed intracranial hypertension or disturbance of consciousness, in isodensity or mixed-density hematomas, and in huge subdural hematomas. There was no specific correlation with age distribution. The pathogenesis of cortical enhancement seemed to be the result of cerebral compression with an increase in the contrast material per unit of volume and a prolonged venous outflow from the hemisphere, but no characteristic feature was detected in the average regional cerebral blood flow in our cases. (author)

  18. Somatostatin-expressing inhibitory interneurons in cortical circuits

    Directory of Open Access Journals (Sweden)

    Iryna Yavorska

    2016-09-01

    Full Text Available Cortical inhibitory neurons exhibit remarkable diversity in their morphology, connectivity, and synaptic properties. Here, we review the function of somatostatin-expressing (SOM inhibitory interneurons, focusing largely on sensory cortex. SOM neurons also comprise a number of subpopulations that can be distinguished by their morphology, input and output connectivity, laminar location, firing properties, and expression of molecular markers. Several of these classes of SOM neurons show unique dynamics and characteristics, such as facilitating synapses, specific axonal projections, intralaminar input, and top-down modulation, which suggest possible computational roles. SOM cells can be differentially modulated by behavioral state depending on their class, sensory system, and behavioral paradigm. The functional effects of such modulation have been studied with optogenetic manipulation of SOM cells, which produces effects on learning and memory, task performance, and the integration of cortical activity. Different classes of SOM cells participate in distinct disinhibitory circuits with different inhibitory partners and in different cortical layers. Through these disinhibitory circuits, SOM cells help encode the behavioral relevance of sensory stimuli by regulating the activity of cortical neurons based on subcortical and intracortical modulatory input. Associative learning leads to long-term changes in the strength of connectivity of SOM cells with other neurons, often influencing the strength of inhibitory input they receive. Thus despite their heterogeneity and variability across cortical areas, current evidence shows that SOM neurons perform unique neural computations, forming not only distinct molecular but also functional subclasses of cortical inhibitory interneurons.

  19. Vector Monte Carlo simulations on atmospheric scattering of polarization qubits.

    Science.gov (United States)

    Li, Ming; Lu, Pengfei; Yu, Zhongyuan; Yan, Lei; Chen, Zhihui; Yang, Chuanghua; Luo, Xiao

    2013-03-01

    In this paper, a vector Monte Carlo (MC) method is proposed to study the influence of atmospheric scattering on polarization qubits for satellite-based quantum communication. The vector MC method utilizes a transmittance method to solve the photon free path for an inhomogeneous atmosphere and random number sampling to determine whether the type of scattering is aerosol scattering or molecule scattering. Simulations are performed for downlink and uplink. The degrees and the rotations of polarization are qualitatively and quantitatively obtained, which agree well with the measured results in the previous experiments. The results show that polarization qubits are well preserved in the downlink and uplink, while the number of received single photons is less than half of the total transmitted single photons for both links. Moreover, our vector MC method can be applied for the scattering of polarized light in other inhomogeneous random media.

  20. Coding and decoding in a point-to-point communication using the polarization of the light beam.

    Science.gov (United States)

    Kavehvash, Z; Massoumian, F

    2008-05-10

    A new technique for coding and decoding of optical signals through the use of polarization is described. In this technique the concept of coding is translated to polarization. In other words, coding is done in such a way that each code represents a unique polarization. This is done by implementing a binary pattern on a spatial light modulator in such a way that the reflected light has the required polarization. Decoding is done by the detection of the received beam's polarization. By linking the concept of coding to polarization we can use each of these concepts in measuring the other one, attaining some gains. In this paper the construction of a simple point-to-point communication where coding and decoding is done through polarization will be discussed.

  1. Broadband polarized emission from P(NDI2OD-T2) polymer.

    Science.gov (United States)

    Ulrich, Steve; Sutch, Tabitha; Szulczewski, Greg; Schweizer, Matthias; Barbosa, Newton; Araujo, Paulo

    2018-05-18

    We investigate the P(NDI2OD-T2) photophysical properties via absorbance and fluorescence spectroscopy, in association with the experimental approach baptized Stokes Spectroscopy, which provides valuable material information through the acquisition and analysis of the fluorescence polarization degree. By changing solvents and using different samples such as solutions, thick, and thin films, it is possible to control the polarization degree spectrum associated to the fluorescence emitted by the polymer's isolated chains and aggregates. We show that the polarization degree could become a powerful tool to obtain information related to the samples morphology, which is connected to their microscopic structure. Moreover, the polarization degree spectra suggest that depolarization effects linked to energy and charge transfer mechanisms are likely taking place. Our findings indicate that P(NDI2OD-T2) polymers are excellent candidates for the advancement of organic technologies that rely on the emission and detection of polarized lights. © 2018 IOP Publishing Ltd.

  2. Reye's syndrome with cortical laminar necrosis: MRI

    International Nuclear Information System (INIS)

    Kinoshita, T.; Takahashi, S.; Ishii, K.; Higano, S.; Matsumoto, K.; Sakamoto, K.; Haginoya, K.; Iinuma, K.

    1996-01-01

    Serial MRI findings are described in two patients with Reye's syndrome, demonstrating diffuse cortical and white matter changes. In the acute stage, T2-weighted images showed subtle but definite laminar high signal and contrast-enhanced T1-weighted images laminar enhancement, along the entire cerebral cortex bilaterally. In the chronic stage, unenhanced T1-weighted images showed diffuse cortical laminar high signal. These characteristic MRI features seemed very similar to those of laminar cortical necrosis in hypoxic brain damage. MRI also displayed delayed white matter changes with cerebral atrophy. (orig.)

  3. CNTF-ACM promotes mitochondrial respiration and oxidative stress in cortical neurons through upregulating L-type calcium channel activity.

    Science.gov (United States)

    Sun, Meiqun; Liu, Hongli; Xu, Huanbai; Wang, Hongtao; Wang, Xiaojing

    2016-09-01

    A specialized culture medium termed ciliary neurotrophic factor-treated astrocyte-conditioned medium (CNTF-ACM) allows investigators to assess the peripheral effects of CNTF-induced activated astrocytes upon cultured neurons. CNTF-ACM has been shown to upregulate neuronal L-type calcium channel current activity, which has been previously linked to changes in mitochondrial respiration and oxidative stress. Therefore, the aim of this study was to evaluate CNTF-ACM's effects upon mitochondrial respiration and oxidative stress in rat cortical neurons. Cortical neurons, CNTF-ACM, and untreated control astrocyte-conditioned medium (UC-ACM) were prepared from neonatal Sprague-Dawley rat cortical tissue. Neurons were cultured in either CNTF-ACM or UC-ACM for a 48-h period. Changes in the following parameters before and after treatment with the L-type calcium channel blocker isradipine were assessed: (i) intracellular calcium levels, (ii) mitochondrial membrane potential (ΔΨm), (iii) oxygen consumption rate (OCR) and adenosine triphosphate (ATP) formation, (iv) intracellular nitric oxide (NO) levels, (v) mitochondrial reactive oxygen species (ROS) production, and (vi) susceptibility to the mitochondrial complex I toxin rotenone. CNTF-ACM neurons displayed the following significant changes relative to UC-ACM neurons: (i) increased intracellular calcium levels (p ACM (p ACM promotes mitochondrial respiration and oxidative stress in cortical neurons through elevating L-type calcium channel activity.

  4. Cortical thickness abnormalities in late adolescence with online gaming addiction.

    Science.gov (United States)

    Yuan, Kai; Cheng, Ping; Dong, Tao; Bi, Yanzhi; Xing, Lihong; Yu, Dahua; Zhao, Limei; Dong, Minghao; von Deneen, Karen M; Liu, Yijun; Qin, Wei; Tian, Jie

    2013-01-01

    Online gaming addiction, as the most popular subtype of Internet addiction, had gained more and more attention from the whole world. However, the structural differences in cortical thickness of the brain between adolescents with online gaming addiction and healthy controls are not well unknown; neither was its association with the impaired cognitive control ability. High-resolution magnetic resonance imaging scans from late adolescence with online gaming addiction (n = 18) and age-, education- and gender-matched controls (n = 18) were acquired. The cortical thickness measurement method was employed to investigate alterations of cortical thickness in individuals with online gaming addiction. The color-word Stroop task was employed to investigate the functional implications of the cortical thickness abnormalities. Imaging data revealed increased cortical thickness in the left precentral cortex, precuneus, middle frontal cortex, inferior temporal and middle temporal cortices in late adolescence with online gaming addiction; meanwhile, the cortical thicknesses of the left lateral orbitofrontal cortex (OFC), insula, lingual gyrus, the right postcentral gyrus, entorhinal cortex and inferior parietal cortex were decreased. Correlation analysis demonstrated that the cortical thicknesses of the left precentral cortex, precuneus and lingual gyrus correlated with duration of online gaming addiction and the cortical thickness of the OFC correlated with the impaired task performance during the color-word Stroop task in adolescents with online gaming addiction. The findings in the current study suggested that the cortical thickness abnormalities of these regions may be implicated in the underlying pathophysiology of online gaming addiction.

  5. Dynamic Causal Modeling of the Cortical Responses to Wrist Perturbations

    Directory of Open Access Journals (Sweden)

    Yuan Yang

    2017-09-01

    Full Text Available Mechanical perturbations applied to the wrist joint typically evoke a stereotypical sequence of cortical and muscle responses. The early cortical responses (<100 ms are thought be involved in the “rapid” transcortical reaction to the perturbation while the late cortical responses (>100 ms are related to the “slow” transcortical reaction. Although previous studies indicated that both responses involve the primary motor cortex, it remains unclear if both responses are engaged by the same effective connectivity in the cortical network. To answer this question, we investigated the effective connectivity cortical network after a “ramp-and-hold” mechanical perturbation, in both the early (<100 ms and late (>100 ms periods, using dynamic causal modeling. Ramp-and-hold perturbations were applied to the wrist joint while the subject maintained an isometric wrist flexion. Cortical activity was recorded using a 128-channel electroencephalogram (EEG. We investigated how the perturbation modulated the effective connectivity for the early and late periods. Bayesian model comparisons suggested that different effective connectivity networks are engaged in these two periods. For the early period, we found that only a few cortico-cortical connections were modulated, while more complicated connectivity was identified in the cortical network during the late period with multiple modulated cortico-cortical connections. The limited early cortical network likely allows for a rapid muscle response without involving high-level cognitive processes, while the complexity of the late network may facilitate coordinated responses.

  6. Human cerebral cortices: signal variation on diffusion-weighted MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Asao, Chiaki [Kumamoto Regional Medical Center, Department of Radiology, Kumamoto (Japan); National Hospital Organization Kumamoto Medical Center, Department of Radiology, Kumamoto (Japan); Hirai, Toshinori; Yamashita, Yasuyuki [Kumamoto University Graduate School of Medical Sciences, Department of Diagnostic Radiology, Kumamoto (Japan); Yoshimatsu, Shunji [National Hospital Organization Kumamoto Medical Center, Department of Radiology, Kumamoto (Japan); Matsukawa, Tetsuya; Imuta, Masanori [Kumamoto Regional Medical Center, Department of Radiology, Kumamoto (Japan); Sagara, Katsuro [Kumamoto Regional Medical Center, Department of Internal Medicine, Kumamoto (Japan)

    2008-03-15

    We have often encountered high signal intensity (SI) of the cingulate gyrus and insula during diffusion-weighted magnetic resonance imaging (DW-MRI) on neurologically healthy adults. To date, cortical signal heterogeneity on DW images has not been investigated systematically. The purpose of our study was to determine whether there is regional signal variation in the brain cortices of neurologically healthy adults on DW-MR images. The SI of the cerebral cortices on DW-MR images at 1.5 T was evaluated in 50 neurologically healthy subjects (34 men, 16 women; age range 33-84 years; mean age 57.6 years). The cortical SI in the cingulate gyrus, insula, and temporal, occipital, and parietal lobes was graded relative to the SI of the frontal lobe. Contrast-to-noise ratios (CNRs) on DW-MR images were compared for each cortical area. Diffusion changes were analyzed by visually assessment of the differences in appearance among the cortices on apparent diffusion coefficient (ADC) maps. Increased SI was frequently seen in the cingulate gyrus and insula regardless of patient age. There were no significant gender- or laterality-related differences. The CNR was significantly higher in the cingulate gyrus and insula than in the other cortices (p <.01), and significant differences existed among the cortical regions (p <.001). There were no apparent ADC differences among the cortices on ADC maps. Regional signal variation of the brain cortices was observed on DW-MR images of healthy subjects, and the cingulate gyrus and insula frequently manifested high SI. These findings may help in the recognition of cortical signal abnormalities as visualized on DW-MR images. (orig.)

  7. Human cerebral cortices: signal variation on diffusion-weighted MR imaging

    International Nuclear Information System (INIS)

    Asao, Chiaki; Hirai, Toshinori; Yamashita, Yasuyuki; Yoshimatsu, Shunji; Matsukawa, Tetsuya; Imuta, Masanori; Sagara, Katsuro

    2008-01-01

    We have often encountered high signal intensity (SI) of the cingulate gyrus and insula during diffusion-weighted magnetic resonance imaging (DW-MRI) on neurologically healthy adults. To date, cortical signal heterogeneity on DW images has not been investigated systematically. The purpose of our study was to determine whether there is regional signal variation in the brain cortices of neurologically healthy adults on DW-MR images. The SI of the cerebral cortices on DW-MR images at 1.5 T was evaluated in 50 neurologically healthy subjects (34 men, 16 women; age range 33-84 years; mean age 57.6 years). The cortical SI in the cingulate gyrus, insula, and temporal, occipital, and parietal lobes was graded relative to the SI of the frontal lobe. Contrast-to-noise ratios (CNRs) on DW-MR images were compared for each cortical area. Diffusion changes were analyzed by visually assessment of the differences in appearance among the cortices on apparent diffusion coefficient (ADC) maps. Increased SI was frequently seen in the cingulate gyrus and insula regardless of patient age. There were no significant gender- or laterality-related differences. The CNR was significantly higher in the cingulate gyrus and insula than in the other cortices (p <.01), and significant differences existed among the cortical regions (p <.001). There were no apparent ADC differences among the cortices on ADC maps. Regional signal variation of the brain cortices was observed on DW-MR images of healthy subjects, and the cingulate gyrus and insula frequently manifested high SI. These findings may help in the recognition of cortical signal abnormalities as visualized on DW-MR images. (orig.)

  8. Are the Symptoms of Parkinsonism Cortical in Origin?

    Directory of Open Access Journals (Sweden)

    Gordon W. Arbuthnott

    Full Text Available We present three reasons to suspect that the major deleterious consequence of dopamine loss from the striatum is a cortical malfunction. We suggest that it is cortex, rather than striatum, that should be considered as the source of the debilitating symptoms of Parkinson's disease (PD since: 1. Cortical synapses onto striatal dendritic spines are lost in PD. 2. All known treatments of the symptoms of PD disrupt beta oscillations. Oscillations that are also disrupted following antidromic activation of cortical neurons. 3. The final output of basal ganglia directly modulates thalamic connections to layer I of frontal cortical areas, regions intimately associated with motor behaviour.These three reasons combined with evidence that the current summary diagram of the basal ganglia involvement in PD is imprecise at best, suggest that a re-orientation of the treatment strategies towards cortical, rather than striatal malfunction, is overdue. Keywords: Parkinson's disease, Deep brain stimulation, Layer I, Motor cortex

  9. Probing the corticospinal link between the motor cortex and motoneurones: some neglected aspects of human motor cortical function

    DEFF Research Database (Denmark)

    Petersen, Nicolas Caesar; Butler, Jane E.; Taylor, Janet L.

    2010-01-01

    of the discharge of motor units have revealed that the rapidly conducting corticospinal axons (stimulated at higher intensities) contribute to drive motoneurones in normal voluntary contractions. There are also major non-linearities generated at a spinal level in the relation between corticospinal output...... magnetic stimulation of the human motor cortex have highlighted the capacity of the cortex to modify its apparent excitability in response to altered afferent inputs, training and various pathologies. Studies using cortical stimulation at 'very low' intensities which elicit only short-latency suppression...

  10. Bipolar Plasma Membrane Distribution of Phosphoinositides and Their Requirement for Auxin-Mediated Cell Polarity and Patterning in Arabidopsis

    NARCIS (Netherlands)

    Tejos, R.; Sauer, M.; Vanneste, S.; Palacios-Gomez, M.; Li, H.; Heilmann, M.; van Wijk, R.; Vermeer, J.E.M.; Heilmann, I.; Munnik, T.; Friml, J.

    2014-01-01

    Cell polarity manifested by asymmetric distribution of cargoes, such as receptors and transporters, within the plasma membrane (PM) is crucial for essential functions in multicellular organisms. In plants, cell polarity (re)establishment is intimately linked to patterning processes. Despite the

  11. Relating Cortical Wave Dynamics to Learning and Remembering

    Directory of Open Access Journals (Sweden)

    Eduardo Mercado III

    2014-12-01

    Full Text Available Electrical waves propagate across sensory and motor cortices in stereotypical patterns. These waves have been described as potentially facilitating sensory processing when they travel through sensory cortex, as guiding movement preparation and performance when they travel across motor cortex, and as possibly promoting synaptic plasticity and the consolidation of memory traces, especially during sleep. Here, an alternative theoretical framework is suggested that integrates Pavlovian hypotheses about learning and cortical function with concepts from contemporary proceduralist theories of memory. The proposed framework postulates that sensory-evoked cortical waves are gradually modified across repeated experiences such that the waves more effectively differentiate sensory events, and so that the waves are more likely to reverberate. It is argued that the qualities of cortical waves—their origins, form, intensity, speed, periodicity, extent, and trajectories —are a function of both the structural organization of neural circuits and ongoing reverberations resulting from previously experienced events. It is hypothesized that experience-dependent cortical plasticity, both in the short- and long-term, modulates the qualities of cortical waves, thereby enabling individuals to make progressively more precise distinctions between complex sensory events, and to reconstruct components of previously experienced events. Unlike most current neurobiological theories of learning and memory mechanisms, this hypothesis does not assume that synaptic plasticity, or any other form of neural plasticity, serves to store physical records of previously experienced events for later reactivation. Rather, the reorganization of cortical circuits may alter the potential for certain wave patterns to arise and persist. Understanding what factors determine the spatiotemporal dynamics of cortical waves, how structural changes affect their qualities, and how wave dynamics

  12. The stability of mandibular prognathism corrected by bilateral sagittal split osteotomies: a comparison of bi-cortical osteosynthesis and mono-cortical osteosynthesis.

    Science.gov (United States)

    Hsu, S S-P; Huang, C-S; Chen, P K-T; Ko, E W-C; Chen, Y-R

    2012-02-01

    This study evaluated the differences in surgical changes and post-surgical changes between bi-cortical and mono-cortical osteosynthesis (MCO) in the correction of skeletal Class III malocclusion with bilateral sagittal split osteotomies (BSSOs). Twenty-five patients had bi-cortical osteosynthesis (BCO), 32 patients had mono-cortical fixation. Lateral and postero-anterior cephalometric radiographs, taken at the time of surgery, before surgery, 1 month after surgery, and on completion of orthodontic treatment (mean 9.9 months after surgery), were obtained for evaluation. Cephalometric analysis and superimposition were used to investigate the surgical and post-surgical changes. Independent t-test was performed to compare the difference between the two groups. Pearson's correlations were tested to evaluate the factors related to the relapse of the mandible. The sagittal relapse rate was 20% in the bi-cortical and 25% in the mono-cortical group. The forward-upward rotation of the mandible in the post-surgical period contributed most of the sagittal relapse. There were no statistically significant differences in sagittal and vertical changes between the two groups during surgery and in the post-surgical period. No factors were found to correlate with post-surgical relapse, but the intergonial width increased more in the bi-cortical group. The study suggested that both methods of skeletal fixation had similar postoperative stability. Copyright © 2011 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  13. Deficits in Beam-Walking After Neonatal Motor Cortical Lesions are not Spared by Fetal Cortical Transplants in Rats

    OpenAIRE

    Swenson, R. S.; Danielsen, E. H.; Klausen, B. S.; Erlich, E.; Zimmer, J.; Castro, A. J.

    1989-01-01

    Adult rats that sustained unilateral motor cortical lesions at birth demonstrated deficits in traversing an elevated narrow beam. These deficits, manifested by hindlimb slips off the edge of the beam, were not spared in animals that received fetal cortical transplants into the lesion cavity immediately after lesion placement.

  14. Effects of vitamin K2 on cortical and cancellous bone mass, cortical osteocyte and lacunar system, and porosity in sciatic neurectomized rats.

    Science.gov (United States)

    Iwamoto, Jun; Matsumoto, Hideo; Takeda, Tsuyoshi; Sato, Yoshihiro; Yeh, James K

    2010-09-01

    The purpose of the present study was to examine the effects of vitamin K2 on cortical and cancellous bone mass, cortical osteocyte and lacunar system, and porosity in sciatic neurectomized rats. Thirty-four female Sprague-Dawley retired breeder rats were randomized into three groups: age-matched control, sciatic neurectomy (NX), and NX + vitamin K2 administration (menatetrenone, 30 mg/kg/day p.o., three times a week). At the end of the 8-week experiment, bone histomorphometric analysis was performed on cortical and cancellous bone of the tibial diaphysis and proximal metaphysis, respectively, and osteocyte lacunar system and porosity were evaluated on cortical bone of the tibial diaphysis. NX decreased cortical and cancellous bone mass compared with age-matched controls as a result of increased endocortical and trabecular bone erosion and decreased trabecular mineral apposition rate (MAR). Vitamin K2 ameliorated the NX-induced increase in bone erosion, prevented the NX-induced decrease in MAR, and increased bone formation rate (BFR/bone surface) in cancellous bone, resulting in an attenuation of NX-induced cancellous bone loss. However, vitamin K2 did not significantly influence cortical bone mass. NX also decreased osteocyte density and lacunar occupancy and increased porosity in cortical bone compared with age-matched controls. Vitamin K2 ameliorated the NX-induced decrease in lacunar occupancy by viable osteocytes and the NX-induced increase in porosity. The present study showed the efficacy of vitamin K2 for cancellous bone mass and cortical lacunar occupancy by viable osteocytes and porosity in sciatic NX rats.

  15. Control of Somatosensory Cortical Processing by Thalamic Posterior Medial Nucleus: A New Role of Thalamus in Cortical Function.

    Directory of Open Access Journals (Sweden)

    Carlos Castejon

    Full Text Available Current knowledge of thalamocortical interaction comes mainly from studying lemniscal thalamic systems. Less is known about paralemniscal thalamic nuclei function. In the vibrissae system, the posterior medial nucleus (POm is the corresponding paralemniscal nucleus. POm neurons project to L1 and L5A of the primary somatosensory cortex (S1 in the rat brain. It is known that L1 modifies sensory-evoked responses through control of intracortical excitability suggesting that L1 exerts an influence on whisker responses. Therefore, thalamocortical pathways targeting L1 could modulate cortical firing. Here, using a combination of electrophysiology and pharmacology in vivo, we have sought to determine how POm influences cortical processing. In our experiments, single unit recordings performed in urethane-anesthetized rats showed that POm imposes precise control on the magnitude and duration of supra- and infragranular barrel cortex whisker responses. Our findings demonstrated that L1 inputs from POm imposed a time and intensity dependent regulation on cortical sensory processing. Moreover, we found that blocking L1 GABAergic inhibition or blocking P/Q-type Ca2+ channels in L1 prevents POm adjustment of whisker responses in the barrel cortex. Additionally, we found that POm was also controlling the sensory processing in S2 and this regulation was modulated by corticofugal activity from L5 in S1. Taken together, our data demonstrate the determinant role exerted by the POm in the adjustment of somatosensory cortical processing and in the regulation of cortical processing between S1 and S2. We propose that this adjustment could be a thalamocortical gain regulation mechanism also present in the processing of information between cortical areas.

  16. A laminar cortical model of stereopsis and 3D surface perception: closure and da Vinci stereopsis.

    Science.gov (United States)

    Cao, Yongqiang; Grossberg, Stephen

    2005-01-01

    A laminar cortical model of stereopsis and 3D surface perception is developed and simulated. The model describes how monocular and binocular oriented filtering interact with later stages of 3D boundary formation and surface filling-in in the LGN and cortical areas V1, V2, and V4. It proposes how interactions between layers 4, 3B, and 2/3 in V1 and V2 contribute to stereopsis, and how binocular and monocular information combine to form 3D boundary and surface representations. The model includes two main new developments: (1) It clarifies how surface-to-boundary feedback from V2 thin stripes to pale stripes helps to explain data about stereopsis. This feedback has previously been used to explain data about 3D figure-ground perception. (2) It proposes that the binocular false match problem is subsumed under the Gestalt grouping problem. In particular, the disparity filter, which helps to solve the correspondence problem by eliminating false matches, is realized using inhibitory interneurons as part of the perceptual grouping process by horizontal connections in layer 2/3 of cortical area V2. The enhanced model explains all the psychophysical data previously simulated by Grossberg and Howe (2003), such as contrast variations of dichoptic masking and the correspondence problem, the effect of interocular contrast differences on stereoacuity, Panum's limiting case, the Venetian blind illusion, stereopsis with polarity-reversed stereograms, and da Vinci stereopsis. It also explains psychophysical data about perceptual closure and variations of da Vinci stereopsis that previous models cannot yet explain.

  17. Reduced cortical thickness in gambling disorder

    DEFF Research Database (Denmark)

    Grant, Jon E; Odlaug, Brian Lawrence; Chamberlain, Samuel R

    2015-01-01

    with significant reductions (average 15.8-19.9 %) in cortical thickness, versus controls, predominantly in right frontal cortical regions. Pronounced right frontal morphometric brain abnormalities occur in gambling disorder, supporting neurobiological overlap with substance disorders and its recent......Gambling disorder has recently been recognized as a prototype 'behavioral addiction' by virtue of its inclusion in the DSM-5 category of 'Substance-Related and Addictive Disorders.' Despite its newly acquired status and prevalence rate of 1-3 % globally, relatively little is known regarding...... the neurobiology of this disorder. The aim of this study was to explore cortical morphometry in untreated gambling disorder, for the first time. Subjects with gambling disorder (N = 16) free from current psychotropic medication or psychiatric comorbidities, and healthy controls (N = 17), were entered...

  18. Autosomal dominant cortical tremor, myoclonus and epilepsy.

    Science.gov (United States)

    Striano, Pasquale; Zara, Federico

    2016-09-01

    The term 'cortical tremor' was first introduced by Ikeda and colleagues to indicate a postural and action-induced shivering movement of the hands which mimics essential tremor, but presents with the electrophysiological findings of cortical reflex myoclonus. The association between autosomal dominant cortical tremor, myoclonus and epilepsy (ADCME) was first recognized in Japanese families and is now increasingly reported worldwide, although it is described using different acronyms (BAFME, FAME, FEME, FCTE and others). The disease usually takes a benign course, although drug-resistant focal seizures or slight intellectual disability occur in some cases. Moreover, a worsening of cortical tremor and myoclonus is common in advanced age. Although not yet recognized by the International League Against Epilepsy (ILAE), this is a well-delineated epilepsy syndrome with remarkable features that clearly distinguishes it from other myoclonus epilepsies. Moreover, genetic studies of these families show heterogeneity and different susceptible chromosomal loci have been identified.

  19. Person identification based on multiscale matching of cortical images

    NARCIS (Netherlands)

    Kruizinga, P; Petkov, N; Hertzberger, B; Serazzi, G

    1995-01-01

    A set of so-called cortical images, motivated by the function of simple cells in the primary visual cortex of mammals, is computed from each of two input images and an image pyramid is constructed for each cortical image. The two sets of cortical image pyramids are matched synchronously and an

  20. Pitch-Responsive Cortical Regions in Congenital Amusia.

    Science.gov (United States)

    Norman-Haignere, Sam V; Albouy, Philippe; Caclin, Anne; McDermott, Josh H; Kanwisher, Nancy G; Tillmann, Barbara

    2016-03-09

    Congenital amusia is a lifelong deficit in music perception thought to reflect an underlying impairment in the perception and memory of pitch. The neural basis of amusic impairments is actively debated. Some prior studies have suggested that amusia stems from impaired connectivity between auditory and frontal cortex. However, it remains possible that impairments in pitch coding within auditory cortex also contribute to the disorder, in part because prior studies have not measured responses from the cortical regions most implicated in pitch perception in normal individuals. We addressed this question by measuring fMRI responses in 11 subjects with amusia and 11 age- and education-matched controls to a stimulus contrast that reliably identifies pitch-responsive regions in normal individuals: harmonic tones versus frequency-matched noise. Our findings demonstrate that amusic individuals with a substantial pitch perception deficit exhibit clusters of pitch-responsive voxels that are comparable in extent, selectivity, and anatomical location to those of control participants. We discuss possible explanations for why amusics might be impaired at perceiving pitch relations despite exhibiting normal fMRI responses to pitch in their auditory cortex: (1) individual neurons within the pitch-responsive region might exhibit abnormal tuning or temporal coding not detectable with fMRI, (2) anatomical tracts that link pitch-responsive regions to other brain areas (e.g., frontal cortex) might be altered, and (3) cortical regions outside of pitch-responsive cortex might be abnormal. The ability to identify pitch-responsive regions in individual amusic subjects will make it possible to ask more precise questions about their role in amusia in future work. Copyright © 2016 the authors 0270-6474/16/362986-09$15.00/0.

  1. Exploring Science Through Polar Exploration

    Science.gov (United States)

    Pfirman, S. L.; Bell, R. E.; Zadoff, L.; Kelsey, R.

    2003-12-01

    Exploring the Poles is a First Year Seminar course taught at Barnard College, Columbia University. First Year Seminars are required of incoming students and are designed to encourage critical analysis in a small class setting with focused discussion. The class links historical polar exploration with current research in order to: introduce non-scientists to the value of environmental science through polar literature; discuss issues related to venturing into the unknown that are of relevance to any discipline: self-reliance, leadership, preparation, decisions under uncertainty; show students the human face of science; change attitudes about science and scientists; use data to engage students in exploring/understanding the environment and help them learn to draw conclusions from data; integrate research and education. These goals are met by bringing analysis of early exploration efforts together with a modern understanding of the polar environment. To date to class has followed the efforts of Nansen in the Fram, Scott and Amundsen in their race to the pole, and Shackleton's Endurance. As students read turn-of-the-century expedition journals, expedition progress is progressively revealed on an interactive map showing the environmental context. To bring the exploration process to life, students are assigned to expedition teams for specific years and the fates of the student "expeditions" are based on their own decisions. For example, in the Arctic, they navigate coastal sea ice and become frozen into the ice north of Siberia, re-creating Nansen's polar drift. Fates of the teams varied tremendously: some safely emerged at Fram Strait in 4 years, while others nearly became hopelessly lost in the Beaufort Gyre. Students thus learn about variability in the current polar environment through first hand experience, enabling them to appreciate the experiences, decisions, and, in some cases, the luck, of polar explorers. Evaluation by the Columbia Center for New Media, Teaching

  2. Canonical cortical circuits: current evidence and theoretical implications

    Directory of Open Access Journals (Sweden)

    Capone F

    2016-04-01

    Full Text Available Fioravante Capone,1,2 Matteo Paolucci,1,2 Federica Assenza,1,2 Nicoletta Brunelli,1,2 Lorenzo Ricci,1,2 Lucia Florio,1,2 Vincenzo Di Lazzaro1,2 1Unit of Neurology, Neurophysiology, Neurobiology, Department of Medicine, Università Campus Bio-Medico di Roma, Rome, Italy; 2Fondazione Alberto Sordi – Research Institute for Aging, Rome, ItalyAbstract: Neurophysiological and neuroanatomical studies have found that the same basic structural and functional organization of neuronal circuits exists throughout the cortex. This kind of cortical organization, termed canonical circuit, has been functionally demonstrated primarily by studies involving visual striate cortex, and then, the concept has been extended to different cortical areas. In brief, the canonical circuit is composed of superficial pyramidal neurons of layers II/III receiving different inputs and deep pyramidal neurons of layer V that are responsible for cortex output. Superficial and deep pyramidal neurons are reciprocally connected, and inhibitory interneurons participate in modulating the activity of the circuit. The main intuition of this model is that the entire cortical network could be modeled as the repetition of relatively simple modules composed of relatively few types of excitatory and inhibitory, highly interconnected neurons. We will review the origin and the application of the canonical cortical circuit model in the six sections of this paper. The first section (The origins of the concept of canonical circuit: the cat visual cortex reviews the experiments performed in the cat visual cortex, from the origin of the concept of canonical circuit to the most recent developments in the modelization of cortex. The second (The canonical circuit in neocortex and third (Toward a canonical circuit in agranular cortex sections try to extend the concept of canonical circuit to other cortical areas, providing some significant examples of circuit functioning in different cytoarchitectonic

  3. Overweight is not associated with cortical thickness alterations in children

    Directory of Open Access Journals (Sweden)

    Rachel Jane Sharkey

    2015-02-01

    Full Text Available IntroductionSeveral studies report an association between body mass index (BMI and cortical thickness in adults. Some studies demonstrate diffuse cortical thinning in obesity, while others report effects in areas that are associated with self-regulation, such as lateral prefrontal cortex. MethodsThis study used multilevel modelling of data from the NIH Pediatric MRI Data Repository, a mixed longitudinal and cross-sectional database, to examine the relationship between cortical thickness and body weight in children. Cortical thickness was computed at 81,942 vertices of 716 MRI scans from 378 children aged between 4 and 18 years. Body mass index Z score for age was computed for each participant. We preformed vertex-wise statistical analysis of the relationship between cortical thickness and BMI, accounting for age and gender. In addition, cortical thickness was extracted from regions of interest in prefrontal cortex and insula.ResultsNo significant association between cortical thickness and BMI was found, either by statistical parametric mapping or by region of interest analysis. Results remained negative when the analysis was restricted to children aged 12-18.ConclusionsThe correlation between BMI and cortical thickness was not found in this large pediatric sample. The association between BMI and cortical thinning develops after adolescence. This has implications for the nature of the relationship between brain anatomy and weight gain.

  4. Significance of frontal cortical atrophy in Parkinson's disease: computed tomographic study

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kyung Sang; Suh, Jung Ho; Chung, Tae Sub; Kim, Dong Ik [College of Medicine, Yonsei University, Seoul (Korea, Republic of)

    1987-10-15

    Fifty-five patients with Parkinson's disease were evaluated clinically and with brain computed tomography (CT) in order to determine the incidence of frontal cortical and subcortical atrophy. Twenty cases of age-related healthy control group were also scanned. The CT criteria of frontal cortical atrophy that was used in this study were the maximum width of frontal hemispheric cortical sulci and width of anterior interhemispheric fissure between frontal lobes comparing with maximum width of hemispheric cortical sulci except frontal lobes. And the criteria of frontal subcortical atrophy were bifrontal index bicaudate index, and Evans index. The results are as follows: 1. Cortical atrophic changes in Parkinson's disease were more prominent in frontal lobe rather than other causes of cortical atrophy. 2. Frontal cortical and subcortical atrophic changes were also more prominent in Parkinson's disease rather than age-related control group. 3. Subcortical atrophic changes in frontal lobe were always associated with cortical atrophic changes. 4. Changes of basal ganglia were hardly seen in Parkinson's disease. 5. Cortical atrophic changes in frontal lobe must be the one of significant findings in Parkinson's disease.

  5. Significance of frontal cortical atrophy in Parkinson's disease: computed tomographic study

    International Nuclear Information System (INIS)

    Lee, Kyung Sang; Suh, Jung Ho; Chung, Tae Sub; Kim, Dong Ik

    1987-01-01

    Fifty-five patients with Parkinson's disease were evaluated clinically and with brain computed tomography (CT) in order to determine the incidence of frontal cortical and subcortical atrophy. Twenty cases of age-related healthy control group were also scanned. The CT criteria of frontal cortical atrophy that was used in this study were the maximum width of frontal hemispheric cortical sulci and width of anterior interhemispheric fissure between frontal lobes comparing with maximum width of hemispheric cortical sulci except frontal lobes. And the criteria of frontal subcortical atrophy were bifrontal index bicaudate index, and Evans index. The results are as follows: 1. Cortical atrophic changes in Parkinson's disease were more prominent in frontal lobe rather than other causes of cortical atrophy. 2. Frontal cortical and subcortical atrophic changes were also more prominent in Parkinson's disease rather than age-related control group. 3. Subcortical atrophic changes in frontal lobe were always associated with cortical atrophic changes. 4. Changes of basal ganglia were hardly seen in Parkinson's disease. 5. Cortical atrophic changes in frontal lobe must be the one of significant findings in Parkinson's disease

  6. Cortical thickness abnormalities in late adolescence with online gaming addiction.

    Directory of Open Access Journals (Sweden)

    Kai Yuan

    Full Text Available Online gaming addiction, as the most popular subtype of Internet addiction, had gained more and more attention from the whole world. However, the structural differences in cortical thickness of the brain between adolescents with online gaming addiction and healthy controls are not well unknown; neither was its association with the impaired cognitive control ability. High-resolution magnetic resonance imaging scans from late adolescence with online gaming addiction (n = 18 and age-, education- and gender-matched controls (n = 18 were acquired. The cortical thickness measurement method was employed to investigate alterations of cortical thickness in individuals with online gaming addiction. The color-word Stroop task was employed to investigate the functional implications of the cortical thickness abnormalities. Imaging data revealed increased cortical thickness in the left precentral cortex, precuneus, middle frontal cortex, inferior temporal and middle temporal cortices in late adolescence with online gaming addiction; meanwhile, the cortical thicknesses of the left lateral orbitofrontal cortex (OFC, insula, lingual gyrus, the right postcentral gyrus, entorhinal cortex and inferior parietal cortex were decreased. Correlation analysis demonstrated that the cortical thicknesses of the left precentral cortex, precuneus and lingual gyrus correlated with duration of online gaming addiction and the cortical thickness of the OFC correlated with the impaired task performance during the color-word Stroop task in adolescents with online gaming addiction. The findings in the current study suggested that the cortical thickness abnormalities of these regions may be implicated in the underlying pathophysiology of online gaming addiction.

  7. Outline of a novel architecture for cortical computation

    OpenAIRE

    Majumdar, Kaushik

    2007-01-01

    In this paper a novel architecture for cortical computation has been proposed. This architecture is composed of computing paths consisting of neurons and synapses only. These paths have been decomposed into lateral, longitudinal and vertical components. Cortical computation has then been decomposed into lateral computation (LaC), longitudinal computation (LoC) and vertical computation (VeC). It has been shown that various loop structures in the cortical circuit play important roles in cortica...

  8. Early and phasic cortical metabolic changes in vestibular neuritis onset.

    Directory of Open Access Journals (Sweden)

    Marco Alessandrini

    Full Text Available Functional brain activation studies described the presence of separate cortical areas responsible for central processing of peripheral vestibular information and reported their activation and interactions with other sensory modalities and the changes of this network associated to strategic peripheral or central vestibular lesions. It is already known that cortical changes induced by acute unilateral vestibular failure (UVF are various and undergo variations over time, revealing different cortical involved areas at the onset and recovery from symptoms. The present study aimed at reporting the earliest change in cortical metabolic activity during a paradigmatic form of UVF such as vestibular neuritis (VN, that is, a purely peripheral lesion of the vestibular system, that offers the opportunity to study the cortical response to altered vestibular processing. This research reports [(18F]fluorodeoxyglucose positron emission tomography brain scan data concerning the early cortical metabolic activity associated to symptoms onset in a group of eight patients suffering from VN. VN patients' cortical metabolic activity during the first two days from symptoms onset was compared to that recorded one month later and to a control healthy group. Beside the known cortical response in the sensorimotor network associated to vestibular deafferentation, we show for the first time the involvement of Entorhinal (BAs 28, 34 and Temporal (BA 38 cortices in early phases of symptomatology onset. We interpret these findings as the cortical counterparts of the attempt to reorient oneself in space counteracting the vertigo symptom (Bas 28, 34 and of the emotional response to the new pathologic condition (BA 38 respectively. These interpretations were further supported by changes in patients' subjective ratings in balance, anxiety, and depersonalization/derealization scores when tested at illness onset and one month later. The present findings contribute in expanding

  9. A marker of animal-vegetal polarity in the egg of the sea urchin Paracentrotus lividus. The pigment band.

    Science.gov (United States)

    Sardet, C; Chang, P

    1985-09-01

    We have examined the subequatorial accumulation of pigment granules (the so-called 'pigment band') in the egg of the sea urchin Paracentrotus lividus, which constitutes an unambiguous marker of animal-vegetal polarity. Most of the reddish pigment granules are situated at the periphery of the egg. They exhibit occasional saltatory movements and can aggregate into large patches. Pigment granules are retained as a band in the isolated cortex when the egg surface complex is isolated by shearing eggs attached to polylysine-coated surfaces with calcium-free isotonic solutions. Pigment granules remain as the main vesicular component of fertilized egg cortices or of unfertilized egg cortices perfused with calcium to provoke cortical granule exocytosis. They may be anchored to the isolated cortex through associations with the plasma membrane and with an extensive subsurface network of rough endoplasmic reticulum (rough ER). Pigment granules contain antimonate-precipitable calcium and, in this respect and many others, resemble acidic vesicles recently identified in the cortex of unpigmented sea urchin eggs. We discuss the similarities observed between granules and acidic vesicles in various urchin egg species and their possible functions.

  10. Aberrant cortical associative plasticity associated with severe adult Tourette syndrome.

    Science.gov (United States)

    Martín-Rodríguez, Juan Francisco; Ruiz-Rodríguez, María Adilia; Palomar, Francisco J; Cáceres-Redondo, María Teresa; Vargas, Laura; Porcacchia, Paolo; Gómez-Crespo, Mercedes; Huertas-Fernández, Ismael; Carrillo, Fátima; Madruga-Garrido, Marcos; Mir, Pablo

    2015-03-01

    Recent studies have shown altered cortical plasticity in adult patients with Tourette syndrome. However, the clinical significance of this finding remains elusive. Motor cortical plasticity was evaluated in 15 adult patients with severe Tourette syndrome and 16 healthy controls using the paired associative stimulation protocol by transcranial magnetic stimulation. Associations between paired associative stimulation-induced plasticity and relevant clinical variables, including cortical excitability, psychiatric comorbidities, drug treatment and tic severity, were assessed. Motor cortical plasticity was abnormally increased in patients with Tourette syndrome compared with healthy subjects. This abnormal plasticity was independently associated with tic severity. Patients with severe Tourette syndrome display abnormally increased cortical associative plasticity. This aberrant cortical plasticity was associated with tic severity, suggesting an underlying mechanism for tic pathophysiology. © 2015 International Parkinson and Movement Disorder Society.

  11. The changing roles of neurons in the cortical subplate

    Directory of Open Access Journals (Sweden)

    Michael J Friedlander

    2009-08-01

    Full Text Available Neurons may serve different functions over the course of an organism’s life. Recent evidence suggests that cortical subplate neurons including those that reside in the white matter may perform longitudinal multi-tasking at different stages of development. These cells play a key role in early cortical development in coordinating thalamocortical reciprocal innervation. At later stages of development, they become integrated within the cortical microcircuitry. This type of longitudinal multi-tasking can enhance the capacity for information processing by populations of cells serving different functions over the lifespan. Subplate cells are initially derived when cells from the ventricular zone underlying the cortex migrate to the cortical preplate that is subsequently split by the differentiating neurons of the cortical plate with some neurons locating in the marginal zone and others settling below in the subplate (SP. While the cortical plate neurons form most of the cortical layers (layers 2-6, the marginal zone neurons form layer 1 and the SP neurons become interstitial cells of the white matter as well as forming a compact sublayer along the bottom of layer 6. After serving as transient innervation targets for thalamocortical axons, most of these cells die and layer 4 neurons become innervated by thalamic axons. However, 10-20% survives, remaining into adulthood along the bottom of layer 6 and as a scattered population of interstitial neurons in the white matter. Surviving subplate cells’ axons project throughout the overlying laminae, reaching layer 1 and issuing axon collaterals within white matter and in lower layer 6. This suggests that they participate in local synaptic networks, as well. Moreover, they receive excitatory and inhibitory synaptic inputs, potentially monitoring outputs from axon collaterals of cortical efferents, from cortical afferents and/or from each other. We explore our understanding of the functional connectivity of

  12. Development of cortical thickness and surface area in autism spectrum disorder

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    Vincent T. Mensen

    2017-01-01

    Full Text Available Autism spectrum disorder (ASD is a neurodevelopmental disorder often associated with changes in cortical volume. The constituents of cortical volume – cortical thickness and surface area – have separable developmental trajectories and are related to different neurobiological processes. However, little is known about the developmental trajectories of cortical thickness and surface area in ASD. In this magnetic resonance imaging (MRI study, we used an accelerated longitudinal design to investigate the cortical development in 90 individuals with ASD and 90 typically developing controls, aged 9 to 20 years. We quantified cortical measures using the FreeSurfer software package, and then used linear mixed model analyses to estimate the developmental trajectories for each cortical measure. Our primary finding was that the development of surface area follows a linear trajectory in ASD that differs from typically developing controls. In typical development, we found a decline in cortical surface area between the ages of 9 and 20 that was absent in ASD. We found this pattern in all regions where developmental trajectories for surface area differed between groups. When we applied a more stringent correction that takes the interdependency of measures into account, this effect on cortical surface area retained significance for left banks of superior temporal sulcus, postcentral area, and right supramarginal area. These areas have previously been implicated in ASD and are involved in the interpretation and processing of audiovisual social stimuli and distinction between self and others. Although some differences in cortical volume and thickness were found, none survived the more stringent correction for multiple testing. This study underscores the importance of distinguishing between cortical surface area and thickness in investigating cortical development, and suggests the development of cortical surface area is of importance to ASD.

  13. Cortical basis of communication: local computation, coordination, attention.

    Science.gov (United States)

    Alexandre, Frederic

    2009-03-01

    Human communication emerges from cortical processing, known to be implemented on a regular repetitive neuronal substratum. The supposed genericity of cortical processing has elicited a series of modeling works in computational neuroscience that underline the information flows driven by the cortical circuitry. In the minimalist framework underlying the current theories for the embodiment of cognition, such a generic cortical processing is exploited for the coordination of poles of representation, as is reported in this paper for the case of visual attention. Interestingly, this case emphasizes how abstract internal referents are built to conform to memory requirements. This paper proposes that these referents are the basis for communication in humans, which is firstly a coordination and an attentional procedure with regard to their congeners.

  14. Cortical Development Requires Mesodermal Expression of Tbx1, a Gene Haploinsufficient in 22q11.2 Deletion Syndrome.

    Science.gov (United States)

    Flore, Gemma; Cioffi, Sara; Bilio, Marchesa; Illingworth, Elizabeth

    2017-03-01

    In mammals, proper temporal control of neurogenesis and neural migration during embryonic development ensures correct formation of the cerebral cortex. Changes in the distribution of cortical projection neurons and interneurons are associated with behavioral disorders and psychiatric diseases, including schizophrenia and autism, suggesting that disrupted cortical connectivity contributes to the brain pathology. TBX1 is the major candidate gene for 22q11.2 deletion syndrome (22q11.2DS), a chromosomal deletion disorder characterized by a greatly increased risk for schizophrenia. We have previously shown that Tbx1 heterozygous mice have reduced prepulse inhibition, a behavioral abnormality that is associated with 22q11.2DS and nonsyndromic schizophrenia. Here, we show that loss of Tbx1 disrupts corticogenesis in mice by promoting premature neuronal differentiation in the medio-lateral embryonic cortex, which gives rise to the somatosensory cortex (S1). In addition, we found altered polarity in both radially migrating excitatory neurons and tangentially migrating inhibitory interneurons. Together, these abnormalities lead to altered lamination in the S1 at the terminal stages of corticogenesis in Tbx1 null mice and similar anomalies in Tbx1 heterozygous adult mice. Finally, we show that mesoderm-specific inactivation of Tbx1 is sufficient to recapitulate the brain phenotype indicating that Tbx1 exerts a cell nonautonomous role in cortical development from the mesoderm. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  15. Polarization of lanthanum nucleus by dynamic polarization method

    International Nuclear Information System (INIS)

    Adachi, Toshikazu; Ishimoto, Shigeru; Masuda, Yasuhiro; Morimoto, Kimio

    1989-01-01

    Preliminary studies have been carried out concerning the application of a dynamic polarization method to polarizing lanthanum fluoride single crystal to be employed as target in experiments with time reversal invariance. The present report briefly outlines the dynamic polarization method and describes some preliminary studies carried out so far. Dynamic polarization is of particular importance because no techniques are currently available that can produce highly polarized static nucleus. Spin interaction between electrons and protons (nuclei) plays a major role in the dynamic polarization method. In a thermal equilibrium state, electrons are polarized almost completely while most protons are not polarized. Positively polarized proton spin is produced by applying microwave to this system. The most hopeful candidate target material is single crystal of LaF 3 containing neodymium because the crystal is chemically stable and easy to handle. The spin direction is of great importance in experiments with time reversal invariance. The spin of neutrons in the target can be cancelled by adjusting the external magnetic field applied to a frozen polarized target. In a frozen spin state, the polarity decreases slowly with a relaxation time that depends on the external magnetic field and temperature. (N.K.)

  16. Negative symptoms in schizophrenia are associated with aberrant striato-cortical connectivity in a rewarded perceptual decision-making task.

    Science.gov (United States)

    Reckless, Greg E; Andreassen, Ole A; Server, Andres; Østefjells, Tiril; Jensen, Jimmy

    2015-01-01

    Negative symptoms in schizophrenia have been associated with structural and functional changes in the prefrontal cortex. They often persist after treatment with antipsychotic medication which targets, in particular, the ventral striatum (VS). As schizophrenia has been suggested to arise from dysfunctional connectivity between neural networks, it is possible that residual aberrant striato-cortical connectivity in medicated patients plays a role in enduring negative symptomology. The present study examined the relationship between striato-cortical connectivity and negative symptoms in medicated schizophrenia patients. We manipulated motivation in a perceptual decision-making task during functional magnetic resonance imaging. Comparing healthy controls (n = 21) and medicated patients with schizophrenia (n = 18) we investigated how motivation-mediated changes in VS activation affected functional connectivity with the frontal cortex, and how changes in connectivity strength from the neutral to motivated condition related to negative symptom severity. A pattern of aberrant striato-cortical connectivity was observed in the presence of intact VS, but altered left inferior frontal gyrus (IFG) motivation-mediated activation in patients. The more severe the patient's negative symptoms, the less the connectivity strength between the right VS and left IFG changed from the neutral to the motivated condition. Despite aberrant striato-cortical connectivity and altered recruitment of the left IFG among patients, both patients and healthy controls adopted a more liberal response strategy in the motivated compared to the neutral condition. The present findings suggest that there is a link between dysfunctional striato-cortical connectivity and negative symptom severity, and offer a possible explanation as to why negative symptoms persist after treatment with antipsychotics.

  17. Contextual control of audiovisual integration in low-level sensory cortices

    NARCIS (Netherlands)

    Van Atteveldt, N.; Peterson, Bradley S; Schroeder, Charles E

    Potential sources of multisensory influences on low-level sensory cortices include direct projections from sensory cortices of different modalities, as well as more indirect feedback inputs from higher order multisensory cortical regions. These multiple architectures may be functionally

  18. Polarized neutrons

    International Nuclear Information System (INIS)

    Williams, W.G.

    1988-01-01

    The book on 'polarized neutrons' is intended to inform researchers in condensed matter physics and chemistry of the diversity of scientific problems that can be investigated using polarized neutron beams. The contents include chapters on:- neutron polarizers and instrumentation, polarized neutron scattering, neutron polarization analysis experiments and precessing neutron polarization. (U.K.)

  19. Analysis of preplate splitting and early cortical development illuminates the biology of neurological disease.

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    Eric C Olson

    2014-11-01

    Full Text Available The development of the layered cerebral cortex starts with a process called preplate splitting. Preplate splitting involves the establishment of prospective cortical layer 6 (L6 neurons within a plexus of pioneer neurons called the preplate. The forming layer 6 splits the preplate into a superficial layer of pioneer neurons called the marginal zone and a deeper layer of pioneer neurons called the subplate. Disruptions of this early developmental event by toxin exposure or mutation are associated with neurological disease including severe intellectual disability. This review explores recent findings that reveal the dynamism of gene expression and morphological differentiation during this early developmental period. Over 1000 genes show expression increases of ≥ 2 fold during this period in differentiating mouse L6 neurons. Surprisingly, 88% of previously identified non-syndromic intellectual disability (NS-ID genes are expressed at this time and show an average expression increase of 1.6 fold in these differentiating L6 neurons. This changing genetic program must, in part, support the dramatic cellular reorganizations that occur during preplate splitting. While different models have been proposed for the formation of a layer of L6 cortical neurons within the preplate, original histological studies and more recent work exploiting transgenic mice suggest that the process is largely driven by the coordinated polarization and coalescence of L6 neurons rather than by cellular translocation or migration. The observation that genes associated with forms of NS-ID are expressed during very early cortical development raises the possibility of studying the relevant biological events at a time point when the cortex is small, contains relatively few cell types, and few functional circuits. This review then outlines how explant models may prove particularly useful in studying the consequence of toxin and mutation on the etiology of some forms of NS-ID.

  20. Polarization of microglia and its role in bacterial sepsis.

    Science.gov (United States)

    Michels, Monique; Sonai, Beatriz; Dal-Pizzol, Felipe

    2017-02-15

    Microglial polarization in response to brain inflammatory conditions is a crescent field in neuroscience. However, the effect of systemic inflammation, and specifically sepsis, is a relatively unexplored field that has great interest and relevance. Sepsis has been associated with both early and late harmful events of the central nervous system, suggesting that there is a close link between sepsis and neuroinflammation. During sepsis evolution it is supposed that microglial could exert both neurotoxic and repairing effects depending on the specific microglial phenotype assumed. In this context, here it was reviewed the role of microglial polarization during sepsis-associated brain dysfunction. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Layer 6 cortical neurons require Reelin-Dab1 signaling for cellular orientation, Golgi deployment, and directed neurite growth into the marginal zone.

    Science.gov (United States)

    O'Dell, Ryan S; Ustine, Candida J M; Cameron, David A; Lawless, Sean M; Williams, Rebecca M; Zipfel, Warren R; Olson, Eric C

    2012-07-07

    The secreted ligand Reelin is believed to regulate the translocation of prospective layer 6 (L6) neocortical neurons into the preplate, a loose layer of pioneer neurons that overlies the ventricular zone. Recent studies have also suggested that Reelin controls neuronal orientation and polarized dendritic growth during this period of early cortical development. To explicitly characterize and quantify how Reelin controls this critical aspect of neurite initiation and growth we used a new ex utero explant model of early cortical development to selectively label a subset of L6 cortical neurons for complete 3-D reconstruction. The total neurite arbor sizes of neurons in Reelin-deficient (reeler mutant) and Dab1-deficient (Reelin-non-responsive scrambler mutant) cortices were quantified and unexpectedly were not different than control arbor lengths (p = 0.51). For each mutant, however, arbor organization was markedly different: mutant neurons manifested more primary processes (neurites emitted directly from the soma) than wild type, and these neurites were longer and displayed less branching. Reeler and scrambler mutant neurites extended tangentially rather than radially, and the Golgi apparatus that normally invests the apical neurite was compact in both reeler and scrambler mutants. Mutant cortices also exhibited a neurite "exclusion zone" which was relatively devoid of L6 neuron neurites and extended at least 15 μm beneath the pial surface, an area corresponding to the marginal zone (MZ) in the wild type explants. The presence of an exclusion zone was also indicated in the orientation of mutant primary neurite and neuronal somata, which failed to adopt angles within ~20˚ of the radial line to the pial surface. Injection of recombinant Reelin to reeler, but not scrambler, mutant cortices fully rescued soma orientation, Golgi organization, and dendritic projection defects within four hrs. These findings indicate Reelin promotes directional dendritic growth into

  2. Cortical heterotopia in Aicardi's syndrome - CT findings

    International Nuclear Information System (INIS)

    Besenski, N.; Bosnjak, V.; Ligutic, I.; Marusic-Della Marina, B.

    1988-01-01

    The case of 5-month-old female infant with Aicardi's syndrome is presented. The main clinical features were severe developmental retardation and intractable epileptic seizures. Ophthalmoscopic examination revealed pathognomonic choriorethinopathy. Ultrasonic examination of the brain detected agenesis of the corpus callosum, whereas CT showed a coexisting malformation of the brain, i.e. cortical heterotopia of the gray matter. Agenesis of the corpus callosum is an entity well-recognized by sonography. However, ultrasonography is an insufficient modality for the visualization of cortical heterotopia which is common to all cases of Aicardi's syndrome. Therefore, in cases of suspected Aicardi's syndrome CT is recommended, as it enables the diagnosis of cortical heterotopia. (orig.)

  3. The cortical signature of impaired gesturing: Findings from schizophrenia

    Directory of Open Access Journals (Sweden)

    Petra Verena Viher

    2018-01-01

    Full Text Available Schizophrenia is characterized by deficits in gesturing that is important for nonverbal communication. Research in healthy participants and brain-damaged patients revealed a left-lateralized fronto-parieto-temporal network underlying gesture performance. First evidence from structural imaging studies in schizophrenia corroborates these results. However, as of yet, it is unclear if cortical thickness abnormalities contribute to impairments in gesture performance. We hypothesized that patients with deficits in gesture production show cortical thinning in 12 regions of interest (ROIs of a gesture network relevant for gesture performance and recognition. Forty patients with schizophrenia and 41 healthy controls performed hand and finger gestures as either imitation or pantomime. Group differences in cortical thickness between patients with deficits, patients without deficits, and controls were explored using a multivariate analysis of covariance. In addition, the relationship between gesture recognition and cortical thickness was investigated. Patients with deficits in gesture production had reduced cortical thickness in eight ROIs, including the pars opercularis of the inferior frontal gyrus, the superior and inferior parietal lobes, and the superior and middle temporal gyri. Gesture recognition correlated with cortical thickness in fewer, but mainly the same, ROIs within the patient sample. In conclusion, our results show that impaired gesture production and recognition in schizophrenia is associated with cortical thinning in distinct areas of the gesture network.

  4. Vacuum polarization energy for general backgrounds in one space dimension

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    H. Weigel

    2017-03-01

    Full Text Available For field theories in one time and one space dimensions we propose an efficient method to compute the vacuum polarization energy of static field configurations that do not allow a decomposition into symmetric and anti-symmetric channels. The method also applies to scenarios in which the masses of the quantum fluctuations at positive and negative spatial infinity are different. As an example we compute the vacuum polarization energy of the kink soliton in the ϕ6 model. We link the dependence of this energy on the position of the soliton to the different masses.

  5. Outline of a novel architecture for cortical computation.

    Science.gov (United States)

    Majumdar, Kaushik

    2008-03-01

    In this paper a novel architecture for cortical computation has been proposed. This architecture is composed of computing paths consisting of neurons and synapses. These paths have been decomposed into lateral, longitudinal and vertical components. Cortical computation has then been decomposed into lateral computation (LaC), longitudinal computation (LoC) and vertical computation (VeC). It has been shown that various loop structures in the cortical circuit play important roles in cortical computation as well as in memory storage and retrieval, keeping in conformity with the molecular basis of short and long term memory. A new learning scheme for the brain has also been proposed and how it is implemented within the proposed architecture has been explained. A few mathematical results about the architecture have been proposed, some of which are without proof.

  6. Investigation of cortical thickness abnormalities in lithium-free adults with bipolar type I disorder using cortical pattern matching

    Science.gov (United States)

    Foland-Ross, Lara C.; Thompson, Paul M.; Sugar, Catherine A.; Madsen, Sarah K.; Shen, Jim K.; Penfold, Conor; Ahlf, Kyle; Rasser, Paul E.; Fischer, Jeffrey; Yang, Yilan; Townsend, Jennifer; Bookheimer, Susan Y.; Altshuler, Lori L.

    2013-01-01

    Objective Several lines of evidence implicate gray matter abnormalities in the prefrontal cortex and anterior cingulate cortex in patients with bipolar disorder. Findings however, have been largely inconsistent across studies. Differences in patients’ medication status or mood state, or the application of traditional volumetric methods that are insensitive to subtle neuroanatomic differences may have contributed to these inconsistent findings. Given this, we used magnetic resonance imaging (MRI) in conjunction with cortical pattern matching methods to assess cortical thickness abnormalities in euthymic bipolar subjects who were not treated with lithium. Method Sixty-five subjects, including 34 lithium-free euthymic subjects with bipolar (type I) disorder and 31 healthy subjects were scanned using magnetic resonance imaging (MRI). Data were processed to measure cortical gray matter thickness. Cortical pattern matching methods associated homologous brain regions across subjects. Spatially normalized thickness maps were analyzed to assess illness effects and associations with clinical variables. Results Relative to healthy subjects, euthymic bipolar I subjects had significantly thinner gray matter in bilateral prefrontal cortex (Brodmann Areas 11, 10, 8 and 44) and left anterior cingulate cortex (Brodmann Areas 24/32). Additionally, thinning in these regions was more pronounced in patients with a history of psychosis. No areas of thicker cortex were detected in bipolar subjects versus healthy subjects. Conclusions Using a technique that is highly sensitive to subtle neuroanatomic differences, significant regional cortical thinning was found in euthymic subjects with bipolar disorder. Clinical implications are discussed. PMID:21285139

  7. Early cenozoic differentiation of polar marine faunas.

    Directory of Open Access Journals (Sweden)

    J Alistair Crame

    Full Text Available The widespread assumption that the origin of polar marine faunas is linked to the onset of major global cooling in the Late Eocene-Early Oligocene is being increasingly challenged. The Antarctic fossil record in particular is suggesting that some modern Southern Ocean taxa may have Early Eocene or even Paleocene origins, i.e. well within the Early Cenozoic greenhouse world. A global analysis of one of the largest marine clades at the present day, the Neogastropoda, indicates that not only is there a decrease in the number of species from the tropics to the poles but also a decrease in the evenness of their distribution. A small number of neogastropod families with predominantly generalist trophic strategies at both poles points to the key role of seasonality in structuring the highest latitude marine assemblages. A distinct latitudinal gradient in seasonality is temperature-invariant and would have operated through periods of global warmth such as the Early Cenozoic. To test this concept a second global analysis was undertaken of earliest Cenozoic (Paleocene neogastropods and this does indeed show a certain degree of faunal differentiation at both poles. The Buccinidae, s.l. is especially well developed at this time, and this is a major generalist taxon at the present day. There is an element of asymmetry associated with this development of Paleocene polar faunas in that those in the south are more strongly differentiated than their northern counterparts; this can in turn be linked to the already substantial isolation of the southern high latitudes. The key role of seasonality in the formation of polar marine faunas has implications for contemporary ecosystem structure and stability.

  8. Altered Regional Brain Cortical Thickness in Pediatric Obstructive Sleep Apnea

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    Paul M. Macey

    2018-01-01

    Full Text Available RationaleObstructive sleep apnea (OSA affects 2–5% of all children and is associated with cognitive and behavioral deficits, resulting in poor school performance. These psychological deficits may arise from brain injury, as seen in preliminary findings of lower gray matter volume among pediatric OSA patients. However, the psychological deficits in OSA are closely related to functions in the cortex, and such brain areas have not been specifically assessed. The objective was to determine whether cortical thickness, a marker of possible brain injury, is altered in children with OSA.MethodsWe examined regional brain cortical thicknesses using high-resolution T1-weighted magnetic resonance images in 16 pediatric OSA patients (8 males; mean age ± SD = 8.4 ± 1.2 years; mean apnea/hypopnea index ± SD = 11 ± 6 events/h and 138 controls (8.3 ± 1.1 years; 62 male; 138 subjects from the NIH Pediatric MRI database to identify cortical thickness differences in pediatric OSA subjects.ResultsCortical thinning occurred in multiple regions including the superior frontal, ventral medial prefrontal, and superior parietal cortices. The left side showed greater thinning in the superior frontal cortex. Cortical thickening was observed in bilateral precentral gyrus, mid-to-posterior insular cortices, and left central gyrus, as well as right anterior insula cortex.ConclusionChanges in cortical thickness are present in children with OSA and likely indicate disruption to neural developmental processes, including maturational patterns of cortical volume increases and synaptic pruning. Regions with thicker cortices may reflect inflammation or astrocyte activation. Both the thinning and thickening associated with OSA in children may contribute to the cognitive and behavioral dysfunction frequently found in the condition.

  9. Regional quantitative analysis of cortical surface maps of FDG PET images

    CERN Document Server

    Protas, H D; Hayashi, K M; Chin Lung, Yu; Bergsneider, M; Sung Cheng, Huang

    2006-01-01

    Cortical surface maps are advantageous for visualizing the 3D profile of cortical gray matter development and atrophy, and for integrating structural and functional images. In addition, cortical surface maps for PET data, when analyzed in conjunction with structural MRI data allow us to investigate, and correct for, partial volume effects. Here we compared quantitative regional PET values based on a 3D cortical surface modeling approach with values obtained directly from the 3D FDG PET images in various atlas-defined regions of interest (ROIs; temporal, parietal, frontal, and occipital lobes). FDG PET and 3D MR (SPGR) images were obtained and aligned to ICBM space for 15 normal subjects. Each image was further elastically warped in 2D parameter space of the cortical surface, to align major cortical sulci. For each point within a 15 mm distance of the cortex, the value of the PET intensity was averaged to give a cortical surface map of FDG uptake. The average PET values on the cortical surface map were calcula...

  10. Synaptic Changes in AMPA Receptor Subunit Expression in Cortical Parvalbumin Interneurons in the Stargazer Model of Absence Epilepsy

    Directory of Open Access Journals (Sweden)

    Nadia K. Adotevi

    2017-12-01

    Full Text Available Feedforward inhibition is essential to prevent run away excitation within the brain. Recent evidence suggests that a loss of feed-forward inhibition in the corticothalamocortical circuitry may underlie some absence seizures. However, it is unclear if this aberration is specifically linked to loss of synaptic excitation onto local fast-spiking parvalbumin-containing (PV+ inhibitory interneurons, which are responsible for mediating feedforward inhibition within cortical networks. We recently reported a global tissue loss of AMPA receptors (AMPARs, and a specific mistrafficking of these AMPARs in PV+ interneurons in the stargazer somatosensory cortex. The current study was aimed at investigating if cellular changes in AMPAR expression were translated into deficits in receptors at specific synapses in the feedforward inhibitory microcircuit. Using western blot immunolabeling on biochemically isolated synaptic fractions, we demonstrate a loss of AMPAR GluA1–4 subunits in the somatosensory cortex of stargazers compared to non-epileptic control mice. Furthermore, using double post-embedding immunogold-cytochemistry, we show a loss of GluA1–4-AMPARs at excitatory synapses onto cortical PV+ interneurons. Altogether, these data indicate a loss of synaptic AMPAR-mediated excitation of cortical PV+ inhibitory neurons. As the cortex is considered the site of initiation of spike wave discharges (SWDs within the corticothalamocortical circuitry, loss of AMPARs at cortical PV+ interneurons likely impairs feed-forward inhibitory output, and contributes to the generation of SWDs and absence seizures in stargazers.

  11. Cortical gyrification is abnormal in children with prenatal alcohol exposure

    Directory of Open Access Journals (Sweden)

    Timothy J. Hendrickson

    2017-01-01

    Conclusions: Abnormalities in cortical development were seen across the brain in children with PAE compared to controls. Cortical gyrification and IQ were strongly correlated, suggesting that examining mechanisms by which alcohol disrupts cortical formation may yield clinically relevant insights and potential directions for early intervention.

  12. Penile density and globally used chemicals in Canadian and Greenland polar bears

    DEFF Research Database (Denmark)

    Sonne, Christian; Dyck, Markus; Rigét, Frank F.

    2015-01-01

    -range dispersed and to biomagnify to very high concentrations in the tissues of Arctic apex predators such as polar bears (Ursus maritimus). A major concern relating to EDCs is their effects on vital organ-tissues such as bone and it is possible that EDCs represent a more serious challenge to the species......' survival than the more conventionally proposed prey reductions linked to climate change. We therefore analyzed penile bone mineral density (BMD) as a key phenotype for reproductive success in 279 polar bear samples born 1990-2000 representing eight polar bear subpopulations. Since EDC concentrations were...... not available from the same specimens, we compared BMD with published literature information on EDC concentrations. Latitudinal and longitudinal BMD and EDC gradients were clearly observed, with Western Hudson bears having the highest BMD and lowest EDCs, and North East Greenland polar bears carrying the lowest...

  13. Response of cortical bone to antiresorptive treatment

    DEFF Research Database (Denmark)

    Hyldstrup, Lars; Jørgensen, J T; Sørensen, T K

    2001-01-01

    of the spine, hip, and forearm. Longitudinal changes in bone densitometry were compared with changes captured by DXR: BMD evaluated by DXR (BMDDXR), cortical thickness of the second metacarpal (CTMC2), and porosity of cortical bone. The expected annual postmenopausal reduction in BMD in the control group...... treatment regimens used in the prevention of osteoporosis....

  14. The cortical structure of consolidated memory: a hypothesis on the role of the cingulate-entorhinal cortical connection.

    Science.gov (United States)

    Insel, Nathan; Takehara-Nishiuchi, Kaori

    2013-11-01

    Daily experiences are represented by networks of neurons distributed across the neocortex, bound together for rapid storage and later retrieval by the hippocampus. While the hippocampus is necessary for retrieving recent episode-based memory associations, over time, consolidation processes take place that enable many of these associations to be expressed independent of the hippocampus. It is generally thought that mechanisms of consolidation involve synaptic weight changes between cortical regions; or, in other words, the formation of "horizontal" cortico-cortical connections. Here, we review anatomical, behavioral, and physiological data which suggest that the connections in and between the entorhinal and cingulate cortices may be uniquely important for the long-term storage of memories that initially depend on the hippocampus. We propose that current theories of consolidation that divide memory into dual systems of hippocampus and neocortex might be improved by introducing a third, middle layer of entorhinal and cingulate allocortex, the synaptic weights within which are necessary and potentially sufficient for maintaining initially hippocampus-dependent associations over long time periods. This hypothesis makes a number of still untested predictions, and future experiments designed to address these will help to fill gaps in the current understanding of the cortical structure of consolidated memory. Copyright © 2013 Elsevier Inc. All rights reserved.

  15. Workshop on polarized neutron filters and polarized pulsed neutron experiments

    International Nuclear Information System (INIS)

    Itoh, Shinichi

    2004-07-01

    The workshop was held in KEK by thirty-three participants on April 26, 2004. The polarized neutron filter method was only discussed. It consists of three parts; the first part was discussed on the polarized neutron methods, the second part on the polarized neutron experiments and the third on the pulse neutron spectrometer and polarized neutron experiments. The six papers were presented such as the polarized 3 He neutron spin filter, neutron polarization by proton polarized filter, soft master and neutron scattering, polarized neutron in solid physics, polarization experiments by chopper spectroscope and neutron polarization system in superHRPD. (S.Y.)

  16. Polarization of concave domains by traveling wave pinning.

    Directory of Open Access Journals (Sweden)

    Slawomir Bialecki

    Full Text Available Pattern formation is one of the most fundamental yet puzzling phenomena in physics and biology. We propose that traveling front pinning into concave portions of the boundary of 3-dimensional domains can serve as a generic gradient-maintaining mechanism. Such a mechanism of domain polarization arises even for scalar bistable reaction-diffusion equations, and, depending on geometry, a number of stationary fronts may be formed leading to complex spatial patterns. The main advantage of the pinning mechanism, with respect to the Turing bifurcation, is that it allows for maintaining gradients in the specific regions of the domain. By linking the instant domain shape with the spatial pattern, the mechanism can be responsible for cellular polarization and differentiation.

  17. Different Stratospheric Polar Vortex States linked to Cold-Spells in North America and Northern Eurasia

    Science.gov (United States)

    Kretschmer, M.; Cohen, J. L.; Runge, J.; Coumou, D.

    2017-12-01

    The stratospheric polar vortex in boreal winter can influence the tropospheric circulation and thereby surface weather in the mid-latitudes. Weak states of the vortex, e.g. associated with Sudden Stratospheric Warmings (SSWs), often precede a negative phase of the North Atlantic Oscillation (NAO), and thus increase the risk of mid-latitude cold-spells especially over Eurasia. Here we show using cluster analysis that next to the well-documented relationship between a zonally symmetric disturbed vortex and a negative NAO, there exists a zonally asymmetric pattern linked to a negative Western Pacific Oscillation (WPO) and cold-spells in the northeastern US, like for example observed in February 2014. The latter is more synoptic in time-scale but occurs more frequently than SSWs. A causal effect network (CEN) approach gives insights into the underlying physical pathways and time-lags showing that high-pressure around Greenland leads to vertical wave activity over eastern Siberia leading to downward propagating waves over Alaska and high pressure over the North Pacific. Moreover, composites propose that a rather strong mid-stratospheric vortex seems to be favorable for this zonally asymmetric and reflective mechanism. Overall, the mutual relationship between stratospheric circulation and high-latitude blocking in both the Pacific and Atlantic Oceans is complex and involves mechanisms operating at different time-scales. Our results suggest that the stratospheric influence on winter circulation should not exclusively be analyzed in terms of a downward propagating Northern Annular Mode (NAM) signal and SSWs. In particular when studying the stratospheric impacts on North American temperature it is crucial to also consider the more transient and zonally asymmetric events which might help to improve seasonal winter predictions for this region.

  18. Abnormalities of fixation, saccade and pursuit in posterior cortical atrophy.

    Science.gov (United States)

    Shakespeare, Timothy J; Kaski, Diego; Yong, Keir X X; Paterson, Ross W; Slattery, Catherine F; Ryan, Natalie S; Schott, Jonathan M; Crutch, Sebastian J

    2015-07-01

    The clinico-neuroradiological syndrome posterior cortical atrophy is the cardinal 'visual dementia' and most common atypical Alzheimer's disease phenotype, offering insights into mechanisms underlying clinical heterogeneity, pathological propagation and basic visual phenomena (e.g. visual crowding). Given the extensive attention paid to patients' (higher order) perceptual function, it is surprising that there have been no systematic analyses of basic oculomotor function in this population. Here 20 patients with posterior cortical atrophy, 17 patients with typical Alzheimer's disease and 22 healthy controls completed tests of fixation, saccade (including fixation/target gap and overlap conditions) and smooth pursuit eye movements using an infrared pupil-tracking system. Participants underwent detailed neuropsychological and neurological examinations, with a proportion also undertaking brain imaging and analysis of molecular pathology. In contrast to informal clinical evaluations of oculomotor dysfunction frequency (previous studies: 38%, current clinical examination: 33%), detailed eyetracking investigations revealed eye movement abnormalities in 80% of patients with posterior cortical atrophy (compared to 17% typical Alzheimer's disease, 5% controls). The greatest differences between posterior cortical atrophy and typical Alzheimer's disease were seen in saccadic performance. Patients with posterior cortical atrophy made significantly shorter saccades especially for distant targets. They also exhibited a significant exacerbation of the normal gap/overlap effect, consistent with 'sticky fixation'. Time to reach saccadic targets was significantly associated with parietal and occipital cortical thickness measures. On fixation stability tasks, patients with typical Alzheimer's disease showed more square wave jerks whose frequency was associated with lower cerebellar grey matter volume, while patients with posterior cortical atrophy showed large saccadic intrusions

  19. Cortical thinning and clinical heterogeneity in amyotrophic lateral sclerosis.

    Science.gov (United States)

    Mezzapesa, Domenico Maria; D'Errico, Eustachio; Tortelli, Rosanna; Distaso, Eugenio; Cortese, Rosa; Tursi, Marianna; Federico, Francesco; Zoccolella, Stefano; Logroscino, Giancarlo; Dicuonzo, Franca; Simone, Isabella Laura

    2013-01-01

    Amyotrophic lateral sclerosis (ALS) has heterogeneous clinical features that could be translated into specific patterns of brain atrophy. In the current study we have evaluated the relationship between different clinical expressions of classical ALS and measurements of brain cortical thickness. Cortical thickness analysis was conducted from 3D-MRI using FreeSurfer software in 29 ALS patients and 20 healthy controls. We explored three clinical traits of the disease, subdividing the patients into two groups for each of them: the bulbar or spinal onset, the higher or lower upper motor neuron burden, the faster or slower disease progression. We used both a whole brain vertex-wise analysis and a ROI analysis on primary motor areas. ALS patients showed cortical thinning in bilateral precentral gyrus, bilateral middle frontal gyrus, right superior temporal gyrus and right occipital cortex. ALS patients with higher upper motor neuron burden showed a significant cortical thinning in the right precentral gyrus and in other frontal extra-motor areas, compared to healthy controls. ALS patients with spinal onset showed a significant cortical thinning in the right precentral gyrus and paracentral lobule, compared to healthy controls. ALS patients with faster progressive disease showed a significant cortical thinning in widespread bilateral frontal and temporal areas, including the bilateral precentral gyrus, compared to healthy controls. Focusing on the primary motor areas, the ROI analysis revealed that the mean cortical thickness values were significantly reduced in ALS patients with higher upper motor neuron burden, spinal onset and faster disease progression related to healthy controls. In conclusion, the thickness of primary motor cortex could be a useful surrogate marker of upper motor neuron involvement in ALS; also our results suggest that cortical thinning in motor and non motor areas seem to reflect the clinical heterogeneity of the disease.

  20. Cortical thinning and clinical heterogeneity in amyotrophic lateral sclerosis.

    Directory of Open Access Journals (Sweden)

    Domenico Maria Mezzapesa

    Full Text Available Amyotrophic lateral sclerosis (ALS has heterogeneous clinical features that could be translated into specific patterns of brain atrophy. In the current study we have evaluated the relationship between different clinical expressions of classical ALS and measurements of brain cortical thickness. Cortical thickness analysis was conducted from 3D-MRI using FreeSurfer software in 29 ALS patients and 20 healthy controls. We explored three clinical traits of the disease, subdividing the patients into two groups for each of them: the bulbar or spinal onset, the higher or lower upper motor neuron burden, the faster or slower disease progression. We used both a whole brain vertex-wise analysis and a ROI analysis on primary motor areas. ALS patients showed cortical thinning in bilateral precentral gyrus, bilateral middle frontal gyrus, right superior temporal gyrus and right occipital cortex. ALS patients with higher upper motor neuron burden showed a significant cortical thinning in the right precentral gyrus and in other frontal extra-motor areas, compared to healthy controls. ALS patients with spinal onset showed a significant cortical thinning in the right precentral gyrus and paracentral lobule, compared to healthy controls. ALS patients with faster progressive disease showed a significant cortical thinning in widespread bilateral frontal and temporal areas, including the bilateral precentral gyrus, compared to healthy controls. Focusing on the primary motor areas, the ROI analysis revealed that the mean cortical thickness values were significantly reduced in ALS patients with higher upper motor neuron burden, spinal onset and faster disease progression related to healthy controls. In conclusion, the thickness of primary motor cortex could be a useful surrogate marker of upper motor neuron involvement in ALS; also our results suggest that cortical thinning in motor and non motor areas seem to reflect the clinical heterogeneity of the disease.

  1. Decreased prefrontal cortical dopamine transmission in alcoholism.

    Science.gov (United States)

    Narendran, Rajesh; Mason, Neale Scott; Paris, Jennifer; Himes, Michael L; Douaihy, Antoine B; Frankle, W Gordon

    2014-08-01

    Basic studies have demonstrated that optimal levels of prefrontal cortical dopamine are critical to various executive functions such as working memory, attention, inhibitory control, and risk/reward decisions, all of which are impaired in addictive disorders such as alcoholism. Based on this and imaging studies of alcoholism that have demonstrated less dopamine in the striatum, the authors hypothesized decreased dopamine transmission in the prefrontal cortex in persons with alcohol dependence. To test this hypothesis, amphetamine and [11C]FLB 457 positron emission tomography were used to measure cortical dopamine transmission in 21 recently abstinent persons with alcohol dependence and 21 matched healthy comparison subjects. [11C]FLB 457 binding potential, specific compared to nondisplaceable uptake (BPND), was measured in subjects with kinetic analysis using the arterial input function both before and after 0.5 mg kg-1 of d-amphetamine. Amphetamine-induced displacement of [11C]FLB 457 binding potential (ΔBPND) was significantly smaller in the cortical regions in the alcohol-dependent group compared with the healthy comparison group. Cortical regions that demonstrated lower dopamine transmission in the alcohol-dependent group included the dorsolateral prefrontal cortex, medial prefrontal cortex, orbital frontal cortex, temporal cortex, and medial temporal lobe. The results of this study, for the first time, unambiguously demonstrate decreased dopamine transmission in the cortex in alcoholism. Further research is necessary to understand the clinical relevance of decreased cortical dopamine as to whether it is related to impaired executive function, relapse, and outcome in alcoholism.

  2. Cortical desmoid of the humerus: radiographic and MRI correlation

    Energy Technology Data Exchange (ETDEWEB)

    Kay, Matthew; Counsel, Peter [Princess Margaret Hospital for Children, Department of Diagnostic Imaging, Perth (Australia); Perth Radiological Clinic, Perth (Australia); Wood, David [Princess Margaret Hospital for Children, Department of Orthopedic Surgery, Perth (Australia); Breidahl, William [Perth Radiological Clinic, Perth (Australia)

    2017-07-15

    Cortical desmoids are self-limiting fibro-osseous lesions commonly occurring at the medial supracondylar femur in active adolescents, at either the origin of the medial head of the gastrocnemius or at the insertion of the adductor magnus aponeurosis. Less commonly, in a similar demographic, cortical desmoids may occur in the proximal humerus medially at the insertion of the pectoralis major muscle or laterally at the insertion of the deltoid. The radiographic appearance of the proximal humerus cortical desmoid has been described previously, but not the MRI appearance. We present the radiographic and MRI appearances of a proximal humerus cortical desmoid in a young adolescent who presented for investigation of right shoulder pain. (orig.)

  3. Cortical desmoid of the humerus: radiographic and MRI correlation

    International Nuclear Information System (INIS)

    Kay, Matthew; Counsel, Peter; Wood, David; Breidahl, William

    2017-01-01

    Cortical desmoids are self-limiting fibro-osseous lesions commonly occurring at the medial supracondylar femur in active adolescents, at either the origin of the medial head of the gastrocnemius or at the insertion of the adductor magnus aponeurosis. Less commonly, in a similar demographic, cortical desmoids may occur in the proximal humerus medially at the insertion of the pectoralis major muscle or laterally at the insertion of the deltoid. The radiographic appearance of the proximal humerus cortical desmoid has been described previously, but not the MRI appearance. We present the radiographic and MRI appearances of a proximal humerus cortical desmoid in a young adolescent who presented for investigation of right shoulder pain. (orig.)

  4. Neutron polarization in polarized 3He targets

    International Nuclear Information System (INIS)

    Friar, J.L.; Gibson, B.F.; Payne, G.L.; Bernstein, A.M.; Chupp, T.E.

    1990-01-01

    Simple formulas for the neutron and proton polarizations in polarized 3 He targets are derived assuming (1) quasielastic final states; (2) no final-state interactions; (3) no meson-exchange currents; (4) large momentum transfers; (5) factorizability of 3 He SU(4) response-function components. Numerical results from a wide variety of bound-state solutions of the Faddeev equations are presented. It is found that this simple model predicts the polarization of neutrons in a fully polarized 3 He target to be 87%, while protons should have a slight residual polarization of -2.7%. Numerical studies show that this model works very well for quasielastic electron scattering

  5. On the homogeneity and heterogeneity of cortical thickness profiles in Homo sapiens sapiens.

    Science.gov (United States)

    Koten, Jan Willem; Schüppen, André; Morozova, Maria; Lehofer, Agnes; Koschutnig, Karl; Wood, Guilherme

    2017-12-20

    Cortical thickness has been investigated since the beginning of the 20th century, but we do not know how similar the cortical thickness profiles among humans are. In this study, the local similarity of cortical thickness profiles was investigated using sliding window methods. Here, we show that approximately 5% of the cortical thickness profiles are similarly expressed among humans while 45% of the cortical thickness profiles show a high level of heterogeneity. Therefore, heterogeneity is the rule, not the exception. Cortical thickness profiles of somatosensory homunculi and the anterior insula are consistent among humans, while the cortical thickness profiles of the motor homunculus are more variable. Cortical thickness profiles of homunculi that code for muscle position and skin stimulation are highly similar among humans despite large differences in sex, education, and age. This finding suggests that the structure of these cortices remains well preserved over a lifetime. Our observations possibly relativize opinions on cortical plasticity.

  6. When measured spin polarization is not spin polarization

    International Nuclear Information System (INIS)

    Dowben, P A; Wu Ning; Binek, Christian

    2011-01-01

    Spin polarization is an unusually ambiguous scientific idiom and, as such, is rarely well defined. A given experimental methodology may allow one to quantify a spin polarization but only in its particular context. As one might expect, these ambiguities sometimes give rise to inappropriate interpretations when comparing the spin polarizations determined through different methods. The spin polarization of CrO 2 and Cr 2 O 3 illustrate some of the complications which hinders comparisons of spin polarization values. (viewpoint)

  7. Linking brain, mind and behavior.

    Science.gov (United States)

    Makeig, Scott; Gramann, Klaus; Jung, Tzyy-Ping; Sejnowski, Terrence J; Poizner, Howard

    2009-08-01

    Cortical brain areas and dynamics evolved to organize motor behavior in our three-dimensional environment also support more general human cognitive processes. Yet traditional brain imaging paradigms typically allow and record only minimal participant behavior, then reduce the recorded data to single map features of averaged responses. To more fully investigate the complex links between distributed brain dynamics and motivated natural behavior, we propose the development of wearable mobile brain/body imaging (MoBI) systems that continuously capture the wearer's high-density electrical brain and muscle signals, three-dimensional body movements, audiovisual scene and point of regard, plus new data-driven analysis methods to model their interrelationships. The new imaging modality should allow new insights into how spatially distributed brain dynamics support natural human cognition and agency.

  8. Effects of Parecoxib and Fentanyl on nociception-induced cortical activity

    Directory of Open Access Journals (Sweden)

    Wang Ying-Wei

    2010-01-01

    Full Text Available Abstract Background Analgesics, including opioids and non-steroid anti-inflammatory drugs reduce postoperative pain. However, little is known about the quantitative effects of these drugs on cortical activity induced by nociceptive stimulation. The aim of the present study was to determine the neural activity in response to a nociceptive stimulus and to investigate the effects of fentanyl (an opioid agonist and parecoxib (a selective cyclooxygenase-2 inhibitor on this nociception-induced cortical activity evoked by tail pinch. Extracellular recordings (electroencephalogram and multi-unit signals were performed in the area of the anterior cingulate cortex while intracellular recordings were made in the primary somatosensory cortex. The effects of parecoxib and fentanyl on induced cortical activity were compared. Results Peripheral nociceptive stimulation in anesthetized rats produced an immediate electroencephalogram (EEG desynchronization resembling the cortical arousal (low-amplitude, fast-wave activity, while the membrane potential switched into a persistent depolarization state. The induced cortical activity was abolished by fentanyl, and the fentanyl's effect was reversed by the opioid receptor antagonist, naloxone. Parecoxib, on the other hand, did not significantly affect the neural activity. Conclusion Cortical activity was modulated by nociceptive stimulation in anesthetized rats. Fentanyl showed a strong inhibitory effect on the nociceptive-stimulus induced cortical activity while parecoxib had no significant effect.

  9. Neuroimaging of malformation of cortical development

    International Nuclear Information System (INIS)

    Zlatareva, D.; Hadjidekov, V.; Tournev, I.; Rossi, A.

    2012-01-01

    Malformations of cortical development (MCD) are heterogeneous group of disease which result from disruption of 3 main stages of cortical development.The common clinical presentation is refractory epilepsy and or developmental delay. The aim of this paper is to describe and analyze magnetic resonance (MR) findings and to present protocol for examination. We analyze MR findings in 17 patients with MCD. The average age was 12,1 year (from 2 months - 57 years). The main indications from reference physician are epilepsy and developmental delay. In 12 patients 1.5T MR was performed, and in 5 - 0.5T. Subependymal heterotopias was found in 6 patients, focal cortical dysplasia - 3. polymicrogyria - 3, schizencephaly - 2, hemimegalencephaly -1, lizencephaly -1, tuberous sclerosis -1. The most common MCD are heterotopias, focal cortical dysplasia, polymicrogyria. schizencephaiy, pachygyria and lizencephaly. In our study the number of patients is not big enough to make a conclusion about frequency of the forms of MCD and our goal is to analyze MR findings which are not well studied in our country. MRI is the method of choice for diagnosis of MCD. The protocol should be different from routine brain protocol to interpret the images with good quality and not miss the pathology. Knowledge of MR findings in MCD would help for genetic counselling in some cases or can predict prognosis in some patients. (authors)

  10. Zic deficiency in the cortical marginal zone and meninges results in cortical lamination defects resembling those in type II lissencephaly.

    Science.gov (United States)

    Inoue, Takashi; Ogawa, Masaharu; Mikoshiba, Katsuhiko; Aruga, Jun

    2008-04-30

    The formation of the highly organized cortical structure depends on the production and correct placement of the appropriate number and types of neurons. The Zic family of zinc-finger transcription factors plays essential roles in regulating the proliferation and differentiation of neuronal progenitors in the medial forebrain and the cerebellum. Examination of the expression of Zic genes demonstrated that Zic1, Zic2, and Zic3 were expressed by the progenitor cells in the septum and cortical hem, the sites of generation of the Cajal-Retzius (CR) cells. Immunohistochemical studies have revealed that Zic proteins were abundantly expressed in the meningeal cells and that the majority of the CR cells distributed in the medial and dorsal cortex also expressed Zic proteins in the mid-late embryonic and postnatal cortical marginal zones. During embryonic cortical development, Zic1/Zic3 double-mutant and hypomorphic Zic2 mutant mice showed a reduction in the number of CR cells in the rostral cortex, whereas the cell number remained unaffected in the caudal cortex. These mutants also showed mislocalization of the CR cells and cortical lamination defects, resembling the changes noted in type II (cobblestone) lissencephaly, throughout the brain. In the Zic1/3 mutant, reduced proliferation of the meningeal cells was observed before the thinner and disrupted organization of the pial basement membrane (BM) with reduced expression of the BM components and the meningeal cell-derived secretory factor. These defects correlated with the changes in the end feet morphology of the radial glial cells. These findings indicate that the Zic genes play critical roles in cortical development through regulating the proliferation of meningeal cells and the pial BM assembly.

  11. Shortened cortical silent period in adductor spasmodic dysphonia: evidence for widespread cortical excitability.

    Science.gov (United States)

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

    2014-02-07

    The purpose of this study was to compare cortical inhibition in the hand region of the primary motor cortex between subjects with focal hand dystonia (FHD), adductor spasmodic dysphonia (AdSD), and healthy controls. Data from 28 subjects were analyzed (FHD n=11, 53.25 ± 8.74 y; AdSD: n=8, 56.38 ± 7.5 y; and healthy controls: n=941.67 ± 10.85 y). All subjects received single pulse TMS to the left motor cortex to measure cortical silent period (CSP) in the right first dorsal interosseus (FDI) muscle. Duration of the CSP was measured and compared across groups. A one-way ANCOVA with age as a covariate revealed a significant group effect (p<0.001). Post hoc analysis revealed significantly longer CSP duration in the healthy group vs. AdSD group (p<0.001) and FHD group (p<0.001). These results suggest impaired intracortical inhibition is a neurophysiologic characteristic of FHD and AdSD. In addition, the shortened CSP in AdSD provides evidence to support a widespread decrease in cortical inhibition in areas of the motor cortex that represent an asymptomatic region of the body. These findings may inform future investigations of differential diagnosis as well as alternative treatments for focal dystonias. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  12. Research progress of anti-icing/deicing technologies for polar ships and offshore platforms

    Directory of Open Access Journals (Sweden)

    XIE Qiang

    2017-01-01

    Full Text Available The polar regions present adverse circumstances of high humidity and strong air-sea exchange. As such, the surfaces of ships and platforms (oil exploiting and drilling platforms serving in polar regions can easily be frozen by ice accretion, which not only affects the operation of the equipment but also threatens safety. This paper summarizes the status of the anti-icing/deicing technologies of both China and abroad for polar ships and offshore platforms, and introduces the various effects of ice accretion on polar ships and offshore platforms, and the resulting safety impacts. It then reviews existing anti-icing/deicing technologies and methods of both China and abroad, including such active deicing methods as electric heating, infrared heating and ultrasonic guided wave deicing, as well as such passive deicing methods as super hydrophobic coating, sacrificial coating, aqueous lubricating layer coating and low cross-link density (with interfacial slippage coating, summarizes their applicability to polar ships and offshore platforms, and finally discusses their advantages/disadvantages.

  13. Abnormalities of cortical structures in adolescent-onset conduct disorder.

    Science.gov (United States)

    Jiang, Y; Guo, X; Zhang, J; Gao, J; Wang, X; Situ, W; Yi, J; Zhang, X; Zhu, X; Yao, S; Huang, B

    2015-12-01

    Converging evidence has revealed both functional and structural abnormalities in adolescents with early-onset conduct disorder (EO-CD). The neurological abnormalities underlying EO-CD may be different from that of adolescent-onset conduct disorder (AO-CD) patients. However, the cortical structure in AO-CD patients remains largely unknown. The aim of the present study was to investigate the cortical alterations in AO-CD patients. We investigated T1-weighted brain images from AO-CD patients and age-, gender- and intelligence quotient-matched controls. Cortical structures including thickness, folding and surface area were measured using the surface-based morphometric method. Furthermore, we assessed impulsivity and antisocial symptoms using the Barratt Impulsiveness Scale (BIS) and the Antisocial Process Screening Device (APSD). Compared with the controls, we found significant cortical thinning in the paralimbic system in AO-CD patients. For the first time, we observed cortical thinning in the precuneus/posterior cingulate cortex (PCC) in AO-CD patients which has not been reported in EO-CD patients. Prominent folding abnormalities were found in the paralimbic structures and frontal cortex while diminished surface areas were shown in the precentral and inferior temporal cortex. Furthermore, cortical thickness of the paralimbic structures was found to be negatively correlated with impulsivity and antisocial behaviors measured by the BIS and APSD, respectively. The present study indicates that AO-CD is characterized by cortical structural abnormalities in the paralimbic system, and, in particular, we highlight the potential role of deficient structures including the precuneus and PCC in the etiology of AO-CD.

  14. Cortical functional connectivity decodes subconscious, task-irrelevant threat-related emotion processing

    OpenAIRE

    Pantazatos, Spiro P.; Talati, Ardesheer; Pavlidis, Paul; Hirsch, Joy

    2012-01-01

    It is currently unclear to what extent cortical structures are required for and engaged during subconscious processing of biologically salient affective stimuli (i.e. the ‘low-road’ vs. ‘many-roads’ hypotheses). Here we show that cortical-cortical and cortical-subcortical functional connectivity (FC) contain substantially more information, relative to subcortical-subcortical FC (i.e. ‘subcortical alarm’ and other limbic regions), that predicts subliminal fearful face processing within individ...

  15. Cortical activity and children's rituals, habits and other repetitive behavior: a visual P300 study.

    Science.gov (United States)

    Evans, David W; Maliken, Ashley

    2011-10-10

    This study examines the link between children's repetitive, ritualistic, behavior and cortical brain activity. Twelve typically developing children between the ages of 6 and 12 years were administered two visual P300, oddball tasks with a 32-electrode electroencephalogram (EEG) system. One of the oddball tasks was specifically designed to reflect sensitivity to asymmetry, a phenomenon common in children and in a variety of disorders involving compulsive behavior. Parents completed the Childhood Routines Inventory. Children's repetitive, compulsive-like behaviors were strongly associated with faster processing of an asymmetrical target stimulus, even when accounting for their P300 latencies on a control task. The research punctuates the continuity between observed brain-behavior links in clinical disorders such as OCD and autism spectrum disorders, and normative variants of repetitive behavior. Copyright © 2011 Elsevier B.V. All rights reserved.

  16. Cortical activity in tinnitus patients and its modification by phonostimulation

    Directory of Open Access Journals (Sweden)

    Katarzyna Pawlak-Osińska

    2013-04-01

    Full Text Available OBJECTIVE: The goal of this study was to observe spontaneous cortical activity and cortical activity modulated by tinnitus-matched sound in tinnitus patients and healthy subjects with no otoneurologic symptoms. METHOD: Data were prospectively collected from 50 tinnitus patients and 25 healthy subjects. Cortical activity was recorded in all subjects with eyes closed and open and during photostimulation, hyperventilation and acoustic stimulation using 19-channel quantitative electroencephalography. The sound applied in the tinnitus patients was individually matched with the ability to mask or equal the tinnitus. The maximal and mean amplitude of the delta, theta, alpha and beta waves and the type and amount of the pathologic EEG patterns were noted during each recording. Differences in cortical localization and the influence of sound stimuli on spontaneous cortical activity were evaluated between the groups. RESULTS: The tinnitus group exhibited decreased delta activity and increased alpha and beta activity. Hyperventilation increased the intensity of the differences. The tinnitus patients had more sharp-slow waves and increased slow wave amplitude. Sound stimuli modified the EEG recordings; the delta and beta wave amplitudes were increased, whereas the alpha-1 wave amplitude was decreased. Acoustic stimulation only slightly affected the temporal region. CONCLUSION: Cortical activity in the tinnitus patients clearly differed from that in healthy subjects, i.e., tinnitus is not a “phantom” sign. The changes in cortical activity included decreased delta wave amplitudes, increased alpha-1, beta-1 and beta-h wave amplitudes and pathologic patterns. Cortical activity modifications occurred predominantly in the temporal region. Acoustic stimulation affected spontaneous cortical activity only in tinnitus patients, and although the applied sound was individually matched, the pathologic changes were only slightly improved.

  17. Cortical Networks for Visual Self-Recognition

    Science.gov (United States)

    Sugiura, Motoaki

    This paper briefly reviews recent developments regarding the brain mechanisms of visual self-recognition. A special cognitive mechanism for visual self-recognition has been postulated based on behavioral and neuropsychological evidence, but its neural substrate remains controversial. Recent functional imaging studies suggest that multiple cortical mechanisms play self-specific roles during visual self-recognition, reconciling the existing controversy. Respective roles for the left occipitotemporal, right parietal, and frontal cortices in symbolic, visuospatial, and conceptual aspects of self-representation have been proposed.

  18. Cortical networks for visual self-recognition

    International Nuclear Information System (INIS)

    Sugiura, Motoaki

    2007-01-01

    This paper briefly reviews recent developments regarding the brain mechanisms of visual self-recognition. A special cognitive mechanism for visual self-recognition has been postulated based on behavioral and neuropsychological evidence, but its neural substrate remains controversial. Recent functional imaging studies suggest that multiple cortical mechanisms play self-specific roles during visual self-recognition, reconciling the existing controversy. Respective roles for the left occipitotemporal, right parietal, and frontal cortices in symbolic, visuospatial, and conceptual aspects of self-representation have been proposed. (author)

  19. Cortical-Cortical Interactions And Sensory Information Processing in Autism

    Science.gov (United States)

    2008-04-30

    significant development for disseminating the results of biomedical research in our lifetime." Sir Paul Nurse , Cancer Research UK Your research papers...of the evidence for local cortical over-connectivity is anecdotal. Belmonte and colleagues suggested the co-morbidity with epilepsy that is highly...Tomma-Halme J, Lahti-Nuuttila P, Service E, Virsu V: Rate of information segregation in developmentally dyslexic children . Brain Lang 2000, 75:66-81

  20. Multimodal surface-based morphometry reveals diffuse cortical atrophy in traumatic brain injury.

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    Sorenson Donna J

    2009-12-01

    Full Text Available Abstract Background Patients with traumatic brain injury (TBI often present with significant cognitive deficits without corresponding evidence of cortical damage on neuroradiological examinations. One explanation for this puzzling observation is that the diffuse cortical abnormalities that characterize TBI are difficult to detect with standard imaging procedures. Here we investigated a patient with severe TBI-related cognitive impairments whose scan was interpreted as normal by a board-certified radiologist in order to determine if quantitative neuroimaging could detect cortical abnormalities not evident with standard neuroimaging procedures. Methods Cortical abnormalities were quantified using multimodal surfaced-based morphometry (MSBM that statistically combined information from high-resolution structural MRI and diffusion tensor imaging (DTI. Normal values of cortical anatomy and cortical and pericortical DTI properties were quantified in a population of 43 healthy control subjects. Corresponding measures from the patient were obtained in two independent imaging sessions. These data were quantified using both the average values for each lobe and the measurements from each point on the cortical surface. The results were statistically analyzed as z-scores from the mean with a p Results The TBI patient showed significant regional abnormalities in cortical thickness, gray matter diffusivity and pericortical white matter integrity that replicated across imaging sessions. Consistent with the patient's impaired performance on neuropsychological tests of executive function, cortical abnormalities were most pronounced in the frontal lobes. Conclusions MSBM is a promising tool for detecting subtle cortical abnormalities with high sensitivity and selectivity. MSBM may be particularly useful in evaluating cortical structure in TBI and other neurological conditions that produce diffuse abnormalities in both cortical structure and tissue properties.

  1. A PKC-dependent recruitment of MMP-2 controls semaphorin-3A growth-promoting effect in cortical dendrites.

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    Bertrand Gonthier

    Full Text Available There is increasing evidence for a crucial role of proteases and metalloproteinases during axon growth and guidance. In this context, we recently described a functional link between the chemoattractive Sema3C and Matrix metalloproteinase 3 (MMP3. Here, we provide data demonstrating the involvement of MMP-2 to trigger the growth-promoting effect of Sema3A in cortical dendrites. The in situ analysis of MMP-2 expression and activity is consistent with a functional growth assay demonstrating in vitro that the pharmacological inhibition of MMP-2 reduces the growth of cortical dendrites in response to Sema3A. Hence, our results suggest that the selective recruitment and activation of MMP-2 in response to Sema3A requires a PKC alpha dependent mechanism. Altogether, we provide a second set of data supporting MMPs as effectors of the growth-promoting effects of semaphorins, and we identify the potential signalling pathway involved.

  2. Green Tea Polyphenols Attenuated Glutamate Excitotoxicity via Antioxidative and Antiapoptotic Pathway in the Primary Cultured Cortical Neurons

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    Lin Cong

    2016-01-01

    Full Text Available Green tea polyphenols are a natural product which has antioxidative and antiapoptotic effects. It has been shown that glutamate excitotoxicity induced oxidative stress is linked to neurodegenerative diseases such as Alzheimer’s disease and Parkinson’s disease. In this study we explored the neuroprotective effect of green teen polyphenols against glutamate excitotoxicity in the primary cultured cortical neurons. We found that green tea polyphenols protected against glutamate induced neurotoxicity in the cortical neurons as measured by MTT and TUNEL assays. Green tea polyphenols were then showed to inhibit the glutamate induced ROS release and SOD activity reduction in the neurons. Furthermore, our results demonstrated that green tea polyphenols restored the dysfunction of mitochondrial pro- or antiapoptotic proteins Bax, Bcl-2, and caspase-3 caused by glutamate. Interestingly, the neuroprotective effect of green tea polyphenols was abrogated when the neurons were incubated with siBcl-2. Taken together, these results demonstrated that green tea polyphenols protected against glutamate excitotoxicity through antioxidative and antiapoptotic pathways.

  3. Oocyte Polarization Is Coupled to the Chromosomal Bouquet, a Conserved Polarized Nuclear Configuration in Meiosis.

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    Yaniv M Elkouby

    2016-01-01

    Full Text Available The source of symmetry breaking in vertebrate oocytes is unknown. Animal-vegetal oocyte polarity is established by the Balbiani body (Bb, a conserved structure found in all animals examined that contains an aggregate of specific mRNAs, proteins, and organelles. The Bb specifies the oocyte vegetal pole, which is key to forming the embryonic body axes as well as the germline in most vertebrates. How Bb formation is regulated and how its asymmetric position is established are unknown. Using quantitative image analysis, we trace oocyte symmetry breaking in zebrafish to a nuclear asymmetry at the onset of meiosis called the chromosomal bouquet. The bouquet is a universal feature of meiosis where all telomeres cluster to one pole on the nuclear envelope, facilitating chromosomal pairing and meiotic recombination. We show that Bb precursor components first localize with the centrosome to the cytoplasm adjacent to the telomere cluster of the bouquet. They then aggregate around the centrosome in a specialized nuclear cleft that we identified, assembling the early Bb. We show that the bouquet nuclear events and the cytoplasmic Bb precursor localization are mechanistically coordinated by microtubules. Thus the animal-vegetal axis of the oocyte is aligned to the nuclear axis of the bouquet. We further show that the symmetry breaking events lay upstream to the only known regulator of Bb formation, the Bucky ball protein. Our findings link two universal features of oogenesis, the Bb and the chromosomal bouquet, to oocyte polarization. We propose that a meiotic-vegetal center couples meiosis and oocyte patterning. Our findings reveal a novel mode of cellular polarization in meiotic cells whereby cellular and nuclear polarity are aligned. We further reveal that in zygotene nests, intercellular cytoplasmic bridges remain between oocytes and that the position of the cytoplasmic bridge coincides with the location of the centrosome meiotic-vegetal organizing center

  4. Influence of vertically and obliquely propagating gravity waves on the polar summer mesosphere

    Science.gov (United States)

    Thurairajah, B.; Siskind, D. E.; Bailey, S. M.

    2017-12-01

    Polar Mesospheric Clouds (PMCs) are sensitive to changes in temperature of the cold polar summer mesosphere, which in turn are modulated by gravity waves (GWs). In this study we investigate the link between PMCs and GWs that propagate both vertically (i.e. wave propagation is directly above the source region) and obliquely (lateral or non-vertical propagation upward but away from the source region). Several observational studies have analyzed the link between PMCs and vertically propagating GWs and have reported both positive and negative correlations. Moreover, while modelling studies have noted the possibility of oblique propagation of GWs from the low-latitude stratosphere to the high-latitude mesosphere, observational studies of the influence of these waves on the polar summer mesosphere are sparse. We present a comprehensive analysis of the influence of vertically and obliquely propagating GWs on the northern hemisphere (NH) polar summer mesosphere using data from 8 PMC seasons. Temperature data from the SOFIE experiment on the AIM satellite and SABER instrument on the TIMED satellite are used to derive GW parameters. SOFIE PMC data in terms of Ice Water Content (IWC) are used to quantify the changes in the polar summer mesosphere. At high latitudes, preliminary analysis of vertically propagating waves indicate a weak but positive correlation between GWs at 50 km and GWs at the PMC altitude of 84 km. Overall there is a negative correlation between GWs at 50 km and IWC and a positive correlation between GWs at 84 km and IWC. These results and the presence of a slanted structure (slanted from the low-latitude stratosphere to the high-latitude mesosphere) in GW momentum flux suggest the possibility of a significant influence of obliquely propagating GWs on the polar summer mesosphere

  5. Growth and Age-Related Abnormalities in Cortical Structure and Fracture Risk

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    Ego Seeman

    2015-12-01

    Full Text Available Vertebral fractures and trabecular bone loss have dominated thinking and research into the pathogenesis and the structural basis of bone fragility during the last 70 years. However, 80% of all fractures are non-vertebral and occur at regions assembled using large amounts of cortical bone; only 20% of fractures are vertebral. Moreover, ~80% of the skeleton is cortical and ~70% of all bone loss is cortical even though trabecular bone is lost more rapidly than cortical bone. Bone is lost because remodelling becomes unbalanced after midlife. Most cortical bone loss occurs by intracortical, not endocortical remodelling. Each remodelling event removes more bone than deposited enlarging existing canals which eventually coalesce eroding and thinning the cortex from 'within.' Thus, there is a need to study the decay of cortical as well as trabecular bone, and to develop drugs that restore the strength of both types of bone. It is now possible to accurately quantify cortical porosity and trabecular decay in vivo. The challenges still to be met are to determine whether measurement of porosity identifies persons at risk for fracture, whether this approach is compliments information obtained using bone densitometry, and whether changes in cortical porosity and other microstructural traits have the sensitivity to serve as surrogates of treatment success or failure.

  6. Wireless Cortical Brain-Machine Interface for Whole-Body Navigation in Primates

    Science.gov (United States)

    Rajangam, Sankaranarayani; Tseng, Po-He; Yin, Allen; Lehew, Gary; Schwarz, David; Lebedev, Mikhail A.; Nicolelis, Miguel A. L.

    2016-03-01

    Several groups have developed brain-machine-interfaces (BMIs) that allow primates to use cortical activity to control artificial limbs. Yet, it remains unknown whether cortical ensembles could represent the kinematics of whole-body navigation and be used to operate a BMI that moves a wheelchair continuously in space. Here we show that rhesus monkeys can learn to navigate a robotic wheelchair, using their cortical activity as the main control signal. Two monkeys were chronically implanted with multichannel microelectrode arrays that allowed wireless recordings from ensembles of premotor and sensorimotor cortical neurons. Initially, while monkeys remained seated in the robotic wheelchair, passive navigation was employed to train a linear decoder to extract 2D wheelchair kinematics from cortical activity. Next, monkeys employed the wireless BMI to translate their cortical activity into the robotic wheelchair’s translational and rotational velocities. Over time, monkeys improved their ability to navigate the wheelchair toward the location of a grape reward. The navigation was enacted by populations of cortical neurons tuned to whole-body displacement. During practice with the apparatus, we also noticed the presence of a cortical representation of the distance to reward location. These results demonstrate that intracranial BMIs could restore whole-body mobility to severely paralyzed patients in the future.

  7. Horizontal integration and cortical dynamics.

    Science.gov (United States)

    Gilbert, C D

    1992-07-01

    We have discussed several results that lead to a view that cells in the visual system are endowed with dynamic properties, influenced by context, expectation, and long-term modifications of the cortical network. These observations will be important for understanding how neuronal ensembles produce a system that perceives, remembers, and adapts to injury. The advantage to being able to observe changes at early stages in a sensory pathway is that one may be able to understand the way in which neuronal ensembles encode and represent images at the level of their receptive field properties, of cortical topographies, and of the patterns of connections between cells participating in a network.

  8. Electrophysiological Data and the Biophysical Modelling of Local Cortical Circuits

    Directory of Open Access Journals (Sweden)

    Dimitris Pinotsis

    2014-03-01

    neuroscience, see e.g. [2] for a review. In summary, neural fields include horizontal intrinsic connections within layers or laminae of the cortical sheet and prescribe the time evolution of cell activity – such as mean depolarization or (average action potential density. These models characterize current fluxes as continuous processes on the cortical sheet, using partial differential equations (PDEs. The key advance that neural field models offer, over other population models (like neural masses, is that they embody spatial parameters (like the density and extent of lateral connections. This allows one to model responses not just in time but also over space. Conversely, these models are particularly useful for explaining observed cortical responses over different spatial scales; for example, with high-density recordings, at the epidural or intracortical level. However, the impact of spatially extensive dynamics is not restricted to expression over space but can also have profound effects on temporal (e.g., spectral responses at one point (or averaged locally over the cortical surface. This means that neural field models may also play a key role in the modelling of non-invasive electrophysiological data that does not resolve spatial activity directly. Our overview comprises two parts: in the first part, we use neural fields to simulate neural activity and distinguish the effects of post synaptic filtering on predicted responses in terms of synaptic rate constants that correspond to different timescales and distinct neurotransmitters. This application of neural fields follows the tradition of many studies, in which neural fields (and mean field models in general have been used to explain cortical activity based on qualitative changes of models activity induced by changes in model parameters, like synaptic efficacy and connection strengths, see e.g.[3–8] . We will focus on the links between neuronal oscillations – mediated by the lateral propagation of neuronal spiking

  9. PET in malformations of cortical development

    International Nuclear Information System (INIS)

    Bouilleret, V.; O'Brien, T.J.; Bouilleret, V.; Bouilleret, V.; Chiron, C.; Chiron, C.

    2009-01-01

    Within the group of malformations of cortical development, focal cortical dysplasia (FCD) are an increasingly recognized cause of intractable epilepsy that can be cured by surgery. The success of cortical resection for intractable epilepsy is highly dependent on the accurate pre-surgical delineation of the regions responsible for generating seizures. [ 18 F]-FDG PET, which images cerebral metabolism studying brain glucose uptake, is the most established functional imaging modality in the evaluation of patients with epilepsy. The aim of this article is to review [ 18 F]-FDG PET usefulness as a pre-surgical tool in the evaluation of medically refractory partial epilepsy. It has an established place in assisting in the localisation and definition of FCD in patients with no lesion, or only a subtle abnormality, on MRI. The role of FDG-PET in defining the extent of the surgical resection is still uncertain and needs to be the focus of future research. (authors)

  10. Cortical thickness differences between bipolar depression and major depressive disorder.

    Science.gov (United States)

    Lan, Martin J; Chhetry, Binod Thapa; Oquendo, Maria A; Sublette, M Elizabeth; Sullivan, Gregory; Mann, J John; Parsey, Ramin V

    2014-06-01

    Bipolar disorder (BD) is a psychiatric disorder with high morbidity and mortality that cannot be distinguished from major depressive disorder (MDD) until the first manic episode. A biomarker able to differentiate BD and MDD could help clinicians avoid risks of treating BD with antidepressants without mood stabilizers. Cortical thickness differences were assessed using magnetic resonance imaging in BD depressed patients (n = 18), MDD depressed patients (n = 56), and healthy volunteers (HVs) (n = 54). A general linear model identified clusters of cortical thickness difference between diagnostic groups. Compared to the HV group, the BD group had decreased cortical thickness in six regions, after controlling for age and sex, located within the frontal and parietal lobes, and the posterior cingulate cortex. Mean cortical thickness changes in clusters ranged from 7.6 to 9.6% (cluster-wise p-values from 1.0 e-4 to 0.037). When compared to MDD, three clusters of lower cortical thickness in BD were identified that overlapped with clusters that differentiated the BD and HV groups. Mean cortical thickness changes in the clusters ranged from 7.5 to 8.2% (cluster-wise p-values from 1.0 e-4 to 0.023). The difference in cortical thickness was more pronounced when the subgroup of subjects with bipolar I disorder (BD-I) was compared to the MDD group. Cortical thickness patterns were distinct between BD and MDD. These results are a step toward developing an imaging test to differentiate the two disorders. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  11. Transcranial magnetic stimulation reveals cortical hyperexcitability in episodic cluster headache.

    Science.gov (United States)

    Cosentino, Guiseppe; Brighina, Filippo; Brancato, Sara; Valentino, Francesca; Indovino, Serena; Fierro, Brigida

    2015-01-01

    Evidence shows involvement of the cerebral cortex in the pathophysiology of cluster headache (CH). Here we investigated cortical excitability in episodic CH patients by using transcranial magnetic stimulation. In 25 patients with episodic CH and 13 healthy subjects we evaluated the motor cortical response to single-pulse (ie, motor threshold, input-output curves, cortical silent period) and paired-pulse (ie, intracortical facilitation, short intracortical inhibition) transcranial magnetic stimulation in both hemispheres. Thirteen patients were evaluated outside bout and the remaining 12 patients inside bout. Our results showed increased slope of the input-output curves after stimulation of both hemispheres in patients outside bout and in the hemisphere contralateral to the headache side in patients inside bout. Increased intracortical facilitation was observed in the hemisphere ipsilateral to the headache side in patients evaluated both outside and inside bout; reduced short intracortical inhibition was observed in patients inside bout ipsilateral to the side of pain. In conclusion, we provide evidence of increased cortical excitability in episodic CH both outside and inside bout, especially in the hemisphere ipsilateral to the side of headache attacks. Our results suggest that an abnormal regulation of cortical excitability could be involved in the pathophysiology of CH. We investigated cortical excitability in episodic cluster headache by using transcranial magnetic stimulation, providing evidence of cortical hyperexcitability in patients both inside and outside bout. We suggest that an abnormal state of cortical excitability could be involved in the pathophysiology of the disease. Copyright © 2015 American Pain Society. Published by Elsevier Inc. All rights reserved.

  12. Stroke rehabilitation using noninvasive cortical stimulation: aphasia.

    Science.gov (United States)

    Mylius, Veit; Zouari, Hela G; Ayache, Samar S; Farhat, Wassim H; Lefaucheur, Jean-Pascal

    2012-08-01

    Poststroke aphasia results from the lesion of cortical areas involved in the motor production of speech (Broca's aphasia) or in the semantic aspects of language comprehension (Wernicke's aphasia). Such lesions produce an important reorganization of speech/language-specific brain networks due to an imbalance between cortical facilitation and inhibition. In fact, functional recovery is associated with changes in the excitability of the damaged neural structures and their connections. Two main mechanisms are involved in poststroke aphasia recovery: the recruitment of perilesional regions of the left hemisphere in case of small lesion and the acquisition of language processing ability in homotopic areas of the nondominant right hemisphere when left hemispheric language abilities are permanently lost. There is some evidence that noninvasive cortical stimulation, especially when combined with language therapy or other therapeutic approaches, can promote aphasia recovery. Cortical stimulation was mainly used to either increase perilesional excitability or reduce contralesional activity based on the concept of reciprocal inhibition and maladaptive plasticity. However, recent studies also showed some positive effects of the reinforcement of neural activities in the contralateral right hemisphere, based on the potential compensatory role of the nondominant hemisphere in stroke recovery.

  13. Brain cortical characteristics of lifetime cognitive ageing.

    Science.gov (United States)

    Cox, Simon R; Bastin, Mark E; Ritchie, Stuart J; Dickie, David Alexander; Liewald, Dave C; Muñoz Maniega, Susana; Redmond, Paul; Royle, Natalie A; Pattie, Alison; Valdés Hernández, Maria; Corley, Janie; Aribisala, Benjamin S; McIntosh, Andrew M; Wardlaw, Joanna M; Deary, Ian J

    2018-01-01

    Regional cortical brain volume is the product of surface area and thickness. These measures exhibit partially distinct trajectories of change across the brain's cortex in older age, but it is unclear which cortical characteristics at which loci are sensitive to cognitive ageing differences. We examine associations between change in intelligence from age 11 to 73 years and regional cortical volume, surface area, and thickness measured at age 73 years in 568 community-dwelling older adults, all born in 1936. A relative positive change in intelligence from 11 to 73 was associated with larger volume and surface area in selective frontal, temporal, parietal, and occipital regions (r cognitive ageing and a thinner cortex for any region. Interestingly, thickness and surface area were phenotypically independent across bilateral lateral temporal loci, whose surface area was significantly related to change in intelligence. These findings suggest that associations between regional cortical volume and cognitive ageing differences are predominantly driven by surface area rather than thickness among healthy older adults. Regional brain surface area has been relatively underexplored, and is a potentially informative biomarker for identifying determinants of cognitive ageing differences.

  14. Multiscale approach including microfibril scale to assess elastic constants of cortical bone based on neural network computation and homogenization method.

    Science.gov (United States)

    Barkaoui, Abdelwahed; Chamekh, Abdessalem; Merzouki, Tarek; Hambli, Ridha; Mkaddem, Ali

    2014-03-01

    The complexity and heterogeneity of bone tissue require a multiscale modeling to understand its mechanical behavior and its remodeling mechanisms. In this paper, a novel multiscale hierarchical approach including microfibril scale based on hybrid neural network (NN) computation and homogenization equations was developed to link nanoscopic and macroscopic scales to estimate the elastic properties of human cortical bone. The multiscale model is divided into three main phases: (i) in step 0, the elastic constants of collagen-water and mineral-water composites are calculated by averaging the upper and lower Hill bounds; (ii) in step 1, the elastic properties of the collagen microfibril are computed using a trained NN simulation. Finite element calculation is performed at nanoscopic levels to provide a database to train an in-house NN program; and (iii) in steps 2-10 from fibril to continuum cortical bone tissue, homogenization equations are used to perform the computation at the higher scales. The NN outputs (elastic properties of the microfibril) are used as inputs for the homogenization computation to determine the properties of mineralized collagen fibril. The mechanical and geometrical properties of bone constituents (mineral, collagen, and cross-links) as well as the porosity were taken in consideration. This paper aims to predict analytically the effective elastic constants of cortical bone by modeling its elastic response at these different scales, ranging from the nanostructural to mesostructural levels. Our findings of the lowest scale's output were well integrated with the other higher levels and serve as inputs for the next higher scale modeling. Good agreement was obtained between our predicted results and literature data. Copyright © 2013 John Wiley & Sons, Ltd.

  15. Degraded attentional modulation of cortical neural populations in strabismic amblyopia.

    Science.gov (United States)

    Hou, Chuan; Kim, Yee-Joon; Lai, Xin Jie; Verghese, Preeti

    2016-01-01

    Behavioral studies have reported reduced spatial attention in amblyopia, a developmental disorder of spatial vision. However, the neural populations in the visual cortex linked with these behavioral spatial attention deficits have not been identified. Here, we use functional MRI-informed electroencephalography source imaging to measure the effect of attention on neural population activity in the visual cortex of human adult strabismic amblyopes who were stereoblind. We show that compared with controls, the modulatory effects of selective visual attention on the input from the amblyopic eye are substantially reduced in the primary visual cortex (V1) as well as in extrastriate visual areas hV4 and hMT+. Degraded attentional modulation is also found in the normal-acuity fellow eye in areas hV4 and hMT+ but not in V1. These results provide electrophysiological evidence that abnormal binocular input during a developmental critical period may impact cortical connections between the visual cortex and higher level cortices beyond the known amblyopic losses in V1 and V2, suggesting that a deficit of attentional modulation in the visual cortex is an important component of the functional impairment in amblyopia. Furthermore, we find that degraded attentional modulation in V1 is correlated with the magnitude of interocular suppression and the depth of amblyopia. These results support the view that the visual suppression often seen in strabismic amblyopia might be a form of attentional neglect of the visual input to the amblyopic eye.

  16. Juxtacortical Lesions and Cortical Thinning in Multiple Sclerosis.

    Science.gov (United States)

    Pareto, D; Sastre-Garriga, J; Auger, C; Vives-Gilabert, Y; Delgado, J; Tintoré, M; Montalban, X; Rovira, A

    2015-12-01

    The role of juxtacortical lesions in brain volume loss in multiple sclerosis has not been fully clarified. The aim of this study was to explore the role of juxtacortical lesions on cortical atrophy and to investigate whether the presence of juxtacortical lesions is related to local cortical thinning in the early stages of MS. A total of 131 patients with clinically isolated syndrome or with relapsing-remitting MS were scanned on a 3T system. Patients with clinically isolated syndrome were classified into 3 groups based on the presence and topography of brain lesions: no lesions (n = 24), only non-juxtacortical lesions (n = 33), and juxtacortical lesions and non-juxtacortical lesions (n = 34). Patients with relapsing-remitting MS were classified into 2 groups: only non-juxtacortical lesions (n = 10) and with non-juxtacortical lesions and juxtacortical lesions (n = 30). A juxtacortical lesion probability map was generated, and cortical thickness was measured by using FreeSurfer. Juxtacortical lesion volume in relapsing-remitting MS was double that of patients with clinically isolated syndrome. The insula showed the highest density of juxtacortical lesions, followed by the temporal, parietal, frontal, and occipital lobes. Patients with relapsing-remitting MS with juxtacortical lesions showed significantly thinner cortices overall and in the parietal and temporal lobes compared with those with clinically isolated syndrome with normal brain MR imaging. The volume of subcortical structures (thalamus, pallidum, putamen, and accumbens) was significantly decreased in relapsing-remitting MS with juxtacortical lesions compared with clinically isolated syndrome with normal brain MR imaging. The spatial distribution of juxtacortical lesions was not found to overlap with areas of cortical thinning. Cortical thinning and subcortical gray matter volume loss in patients with a clinically isolated syndrome or relapsing-remitting MS was related to the presence of juxtacortical

  17. Research on generating various polarization-modes in polarized illumination system

    Science.gov (United States)

    Huang, Jinping; Lin, Wumei; Fan, Zhenjie

    2013-08-01

    With the increase of the numerical aperture (NA), the polarization of light affects the imaging quality of projection lens more significantly. On the contrary, according to the mask pattern, the resolution of projection lens can be improved by using the polarized illumination. That is to say, using the corresponding polarized beam (or polarization-mode) along with the off-axis illumination will improve the resolution and the imaging quality of the of projection lens. Therefore, the research on the generation of various polarization modes and its conversion methods become more and more important. In order to realize various polarization modes in polarized illumination system, after read a lot of references, we provide a way that fitting for the illumination system with the wavelength of 193nm.Six polarization-modes and a depolarized mode are probably considered. Wave-plate stack is used to generate linearly polarization-mode, which have a higher degree polarization. In order to generate X-Y and Y-X polarization mode, the equipment consisting of four sectors of λ/2 wave plate was used. We combined 16 sectors of λ/2 wave plate which have different orientations of the "slow" axis to generate radial and azimuthal polarization. Finally, a multi-polarization control device was designed. Using the kind of multi-polarization control device which applying this method could help to choose the polarization modes conveniently and flexibility for the illumination system.

  18. Polarization properties of linearly polarized parabolic scaling Bessel beams

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Mengwen; Zhao, Daomu, E-mail: zhaodaomu@yahoo.com

    2016-10-07

    The intensity profiles for the dominant polarization, cross polarization, and longitudinal components of modified parabolic scaling Bessel beams with linear polarization are investigated theoretically. The transverse intensity distributions of the three electric components are intimately connected to the topological charge. In particular, the intensity patterns of the cross polarization and longitudinal components near the apodization plane reflect the sign of the topological charge. - Highlights: • We investigated the polarization properties of modified parabolic scaling Bessel beams with linear polarization. • We studied the evolution of transverse intensity profiles for the three components of these beams. • The intensity patterns of the cross polarization and longitudinal components can reflect the sign of the topological charge.

  19. Usher syndrome: molecular links of pathogenesis, proteins and pathways.

    Science.gov (United States)

    Kremer, Hannie; van Wijk, Erwin; Märker, Tina; Wolfrum, Uwe; Roepman, Ronald

    2006-10-15

    Usher syndrome is the most common form of deaf-blindness. The syndrome is both clinically and genetically heterogeneous, and to date, eight causative genes have been identified. The proteins encoded by these genes are part of a dynamic protein complex that is present in hair cells of the inner ear and in photoreceptor cells of the retina. The localization of the Usher proteins and the phenotype in animal models indicate that the Usher protein complex is essential in the morphogenesis of the stereocilia bundle in hair cells and in the calycal processes of photoreceptor cells. In addition, the Usher proteins are important in the synaptic processes of both cell types. The association of other proteins with the complex indicates functional links to a number of basic cell-biological processes. Prominently present is the connection to the dynamics of the actin cytoskeleton, involved in cellular morphology, cell polarity and cell-cell interactions. The Usher protein complex can also be linked to the cadherins/catenins in the adherens junction-associated protein complexes, suggesting a role in cell polarity and tissue organization. A third link can be established to the integrin transmembrane signaling network. The Usher interactome, as outlined in this review, participates in pathways common in inner ear and retina that are disrupted in the Usher syndrome.

  20. Basal Forebrain Gating by Somatostatin Neurons Drives Prefrontal Cortical Activity.

    Science.gov (United States)

    Espinosa, Nelson; Alonso, Alejandra; Morales, Cristian; Espinosa, Pedro; Chávez, Andrés E; Fuentealba, Pablo

    2017-11-17

    The basal forebrain provides modulatory input to the cortex regulating brain states and cognitive processing. Somatostatin-expressing neurons constitute a heterogeneous GABAergic population known to functionally inhibit basal forebrain cortically projecting cells thus favoring sleep and cortical synchronization. However, it remains unclear if somatostatin cells can regulate population activity patterns in the basal forebrain and modulate cortical dynamics. Here, we demonstrate that somatostatin neurons regulate the corticopetal synaptic output of the basal forebrain impinging on cortical activity and behavior. Optogenetic inactivation of somatostatin neurons in vivo rapidly modified neural activity in the basal forebrain, with the consequent enhancement and desynchronization of activity in the prefrontal cortex, reflected in both neuronal spiking and network oscillations. Cortical activation was partially dependent on cholinergic transmission, suppressing slow waves and potentiating gamma oscillations. In addition, recruitment dynamics was cell type-specific, with interneurons showing similar temporal profiles, but stronger responses than pyramidal cells. Finally, optogenetic stimulation of quiescent animals during resting periods prompted locomotor activity, suggesting generalized cortical activation and increased arousal. Altogether, we provide physiological and behavioral evidence indicating that somatostatin neurons are pivotal in gating the synaptic output of the basal forebrain, thus indirectly controlling cortical operations via both cholinergic and non-cholinergic mechanisms. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  1. Influences of brain development and ageing on cortical interactive networks.

    Science.gov (United States)

    Zhu, Chengyu; Guo, Xiaoli; Jin, Zheng; Sun, Junfeng; Qiu, Yihong; Zhu, Yisheng; Tong, Shanbao

    2011-02-01

    To study the effect of brain development and ageing on the pattern of cortical interactive networks. By causality analysis of multichannel electroencephalograph (EEG) with partial directed coherence (PDC), we investigated the different neural networks involved in the whole cortex as well as the anterior and posterior areas in three age groups, i.e., children (0-10 years), mid-aged adults (26-38 years) and the elderly (56-80 years). By comparing the cortical interactive networks in different age groups, the following findings were concluded: (1) the cortical interactive network in the right hemisphere develops earlier than its left counterpart in the development stage; (2) the cortical interactive network of anterior cortex, especially at C3 and F3, is demonstrated to undergo far more extensive changes, compared with the posterior area during brain development and ageing; (3) the asymmetry of the cortical interactive networks declines during ageing with more loss of connectivity in the left frontal and central areas. The age-related variation of cortical interactive networks from resting EEG provides new insights into brain development and ageing. Our findings demonstrated that the PDC analysis of EEG is a powerful approach for characterizing the cortical functional connectivity during brain development and ageing. Copyright © 2010 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  2. Dual descriptors within the framework of spin-polarized density functional theory.

    Science.gov (United States)

    Chamorro, E; Pérez, P; Duque, M; De Proft, F; Geerlings, P

    2008-08-14

    Spin-polarized density functional theory (SP-DFT) allows both the analysis of charge-transfer (e.g., electrophilic and nucleophilic reactivity) and of spin-polarization processes (e.g., photophysical changes arising from electron transitions). In analogy with the dual descriptor introduced by Morell et al. [J. Phys. Chem. A 109, 205 (2005)], we introduce new dual descriptors intended to simultaneously give information of the molecular regions where the spin-polarization process linking states of different multiplicity will drive electron density and spin density changes. The electronic charge and spin rearrangement in the spin forbidden radiative transitions S(0)-->T(n,pi(*)) and S(0)-->T(pi,pi(*)) in formaldehyde and ethylene, respectively, have been used as benchmark examples illustrating the usefulness of the new spin-polarization dual descriptors. These quantities indicate those regions where spin-orbit coupling effects are at work in such processes. Additionally, the qualitative relationship between the topology of the spin-polarization dual descriptors and the vertical singlet triplet energy gap in simple substituted carbene series has been also discussed. It is shown that the electron density and spin density rearrangements arise in agreement with spectroscopic experimental evidence and other theoretical results on the selected target systems.

  3. rab3 mediates cortical granule exocytosis in the sea urchin egg.

    Science.gov (United States)

    Conner, S; Wessel, G M

    1998-11-15

    Egg activation at fertilization in the sea urchin results in the exocytosis of approximately 15,000 cortical granules that are docked at the plasma membrane. Previously, we reported that several integral membrane proteins modeled in the SNARE hypothesis, synaptotagmin, VAMP, and syntaxin, in addition to a small GTPase of the ras superfamily, rab3, were present on cortical granules (Conner, S., Leaf, D., and Wessel, G., Mol. Reprod. Dev. 48, 1-13, 1997). Here we report that rab3 is associated with cortical granules throughout oogenesis, during cortical granule translocation, and while docked at the egg plasma membrane. Following cortical granule exocytosis, however, rab3 reassociates with a different population of vesicles, at least some of which are of endocytic origin. Because of its selective association with cortical granules in eggs and oocytes, we hypothesize that rab3 functions in cortical granule exocytosis. To test this hypothesis, we used a strategy of interfering with rab3 function by peptide competition with its effector domain, a conserved region within specific rab types. We first identified the effector domain sequence in Lytechinus variegatus eggs and find the sequence 94% identical to the effector domain of rab3 in Stronglocentrotus purpuratus. Then, with synthetic peptides to different regions of the rab3 protein, we find that cortical granule exocytosis is inhibited in eggs injected with effector domain peptides, but not with peptides from the hypervariable region or with a scrambled effector peptide. Additionally, effector-peptide-injected eggs injected with IP3 are blocked in their ability to exocytose cortical granules, suggesting that the inhibition is directly on the membrane fusion event and not the result of interference with the signal transduction mechanism leading to calcium release. We interpret these results to mean that rab3 functions in the regulation of cortical granule exocytosis following vesicle docking. Copyright 1998 Academic

  4. Polarized nuclear target based on parahydrogen induced polarization

    OpenAIRE

    Budker, D.; Ledbetter, M. P.; Appelt, S.; Bouchard, L. S.; Wojtsekhowski, B.

    2012-01-01

    We discuss a novel concept of a polarized nuclear target for accelerator fixed-target scattering experiments, which is based on parahydrogen induced polarization (PHIP). One may be able to reach a 33% free-proton polarization in the ethane molecule. The potential advantages of such a target include operation at zero magnetic field, fast ($\\sim$100 Hz) polarization reversal, and operation with large intensity of an electron beam.

  5. In vivo characterization of cortical and white matter neuroaxonal pathology in early multiple sclerosis.

    Science.gov (United States)

    Granberg, Tobias; Fan, Qiuyun; Treaba, Constantina Andrada; Ouellette, Russell; Herranz, Elena; Mangeat, Gabriel; Louapre, Céline; Cohen-Adad, Julien; Klawiter, Eric C; Sloane, Jacob A; Mainero, Caterina

    2017-11-01

    Neuroaxonal pathology is a main determinant of disease progression in multiple sclerosis; however, its underlying pathophysiological mechanisms, including its link to inflammatory demyelination and temporal occurrence in the disease course are still unknown. We used ultra-high field (7 T), ultra-high gradient strength diffusion and T1/T2-weighted myelin-sensitive magnetic resonance imaging to characterize microstructural changes in myelin and neuroaxonal integrity in the cortex and white matter in early stage multiple sclerosis, their distribution in lesional and normal-appearing tissue, and their correlations with neurological disability. Twenty-six early stage multiple sclerosis subjects (disease duration ≤5 years) and 24 age-matched healthy controls underwent 7 T T2*-weighted imaging for cortical lesion segmentation and 3 T T1/T2-weighted myelin-sensitive imaging and neurite orientation dispersion and density imaging for assessing microstructural myelin, axonal and dendrite integrity in lesional and normal-appearing tissue of the cortex and the white matter. Conventional mean diffusivity and fractional anisotropy metrics were also assessed for comparison. Cortical lesions were identified in 92% of early multiple sclerosis subjects and they were characterized by lower intracellular volume fraction (P = 0.015 by paired t-test), lower myelin-sensitive contrast (P = 0.030 by related-samples Wilcoxon signed-rank test) and higher mean diffusivity (P = 0.022 by related-samples Wilcoxon signed-rank test) relative to the contralateral normal-appearing cortex. Similar findings were observed in white matter lesions relative to normal-appearing white matter (all P test) and lower fractional anisotropy (P Wilcoxon signed-rank test) suggestive of less coherent underlying fibre orientation. Additionally, the normal-appearing white matter in multiple sclerosis subjects had diffusely lower intracellular volume fractions than the white matter in controls (P = 0.029 by unpaired

  6. Anterior Cortical Development During Adolescence in Bipolar Disorder.

    Science.gov (United States)

    Najt, Pablo; Wang, Fei; Spencer, Linda; Johnston, Jennifer A Y; Cox Lippard, Elizabeth T; Pittman, Brian P; Lacadie, Cheryl; Staib, Lawrence H; Papademetris, Xenophon; Blumberg, Hilary P

    2016-02-15

    Increasing evidence supports a neurodevelopmental model for bipolar disorder (BD), with adolescence as a critical period in its development. Developmental abnormalities of anterior paralimbic and heteromodal frontal cortices, key structures in emotional regulation processes and central in BD, are implicated. However, few longitudinal studies have been conducted, limiting understanding of trajectory alterations in BD. In this study, we performed longitudinal neuroimaging of adolescents with and without BD and assessed volume changes over time, including changes in tissue overall and within gray and white matter. Larger decreases over time in anterior cortical volumes in the adolescents with BD were hypothesized. Gray matter decreases and white matter increases are typically observed during adolescence in anterior cortices. It was hypothesized that volume decreases over time in BD would reflect alterations in those processes, showing larger gray matter contraction and decreased white matter expansion. Two high-resolution magnetic resonance imaging scans were obtained approximately 2 years apart for 35 adolescents with bipolar I disorder (BDI) and 37 healthy adolescents. Differences over time between groups were investigated for volume overall and specifically for gray and white matter. Relative to healthy adolescents, adolescents with BDI showed greater volume contraction over time in a region including insula and orbitofrontal, rostral, and dorsolateral prefrontal cortices (p adolescence in BDI in anterior cortices, including altered developmental trajectories of anterior gray and white matter. Published by Elsevier Inc.

  7. Identifying Network Motifs that Buffer Front-to-Back Signaling in Polarized Neutrophils

    Directory of Open Access Journals (Sweden)

    Yanqin Wang

    2013-05-01

    Full Text Available Neutrophil polarity relies on local, mutual inhibition to segregate incompatible signaling circuits to the leading and trailing edges. Mutual inhibition alone should lead to cells having strong fronts and weak backs or vice versa. However, analysis of cell-to-cell variation in human neutrophils revealed that back polarity remains consistent despite changes in front strength. How is this buffering achieved? Pharmacological perturbations and mathematical modeling revealed a functional role for microtubules in buffering back polarity by mediating positive, long-range crosstalk from front to back; loss of microtubules inhibits buffering and results in anticorrelation between front and back signaling. Furthermore, a systematic, computational search of network topologies found that a long-range, positive front-to-back link is necessary for back buffering. Our studies suggest a design principle that can be employed by polarity networks: short-range mutual inhibition establishes distinct signaling regions, after which directed long-range activation insulates one region from variations in the other.

  8. Imprinting and recalling cortical ensembles.

    Science.gov (United States)

    Carrillo-Reid, Luis; Yang, Weijian; Bando, Yuki; Peterka, Darcy S; Yuste, Rafael

    2016-08-12

    Neuronal ensembles are coactive groups of neurons that may represent building blocks of cortical circuits. These ensembles could be formed by Hebbian plasticity, whereby synapses between coactive neurons are strengthened. Here we report that repetitive activation with two-photon optogenetics of neuronal populations from ensembles in the visual cortex of awake mice builds neuronal ensembles that recur spontaneously after being imprinted and do not disrupt preexisting ones. Moreover, imprinted ensembles can be recalled by single- cell stimulation and remain coactive on consecutive days. Our results demonstrate the persistent reconfiguration of cortical circuits by two-photon optogenetics into neuronal ensembles that can perform pattern completion. Copyright © 2016, American Association for the Advancement of Science.

  9. Cortical Brain Atrophy and Intra-Individual Variability in Neuropsychological Test Performance in HIV Disease

    Science.gov (United States)

    HINES, Lindsay J.; MILLER, Eric N.; HINKIN, Charles H.; ALGER, Jeffery R.; BARKER, Peter; GOODKIN, Karl; MARTIN, Eileen M.; MARUCA, Victoria; RAGIN, Ann; SACKTOR, Ned; SANDERS, Joanne; SELNES, Ola; BECKER, James T.

    2015-01-01

    Objective To characterize the relationship between dispersion-based intra-individual variability (IIVd) in neuropsychological test performance and brain volume among HIV seropositive and seronegative men and to determine the effects of cardiovascular risk and HIV infection on this relationship. Methods Magnetic Resonance Imaging (MRI) was used to acquire high-resolution neuroanatomic data from 147 men age 50 and over, including 80 HIV seropositive (HIV+) and 67 seronegative controls (HIV−) in this cross-sectional cohort study. Voxel Based Morphometry was used to derive volumetric measurements at the level of the individual voxel. These brain structure maps were analyzed using Statistical Parametric Mapping (SPM2). IIVd was measured by computing intra-individual standard deviations (ISD’s) from the standardized performance scores of five neuropsychological tests: Wechsler Memory Scale-III Visual Reproduction I and II, Logical Memory I and II, Wechsler Adult Intelligence Scale-III Letter Number Sequencing. Results Total gray matter (GM) volume was inversely associated with IIVd. Among all subjects, IIVd -related GM atrophy was observed primarily in: 1) the inferior frontal gyrus bilaterally, the left inferior temporal gyrus extending to the supramarginal gyrus, spanning the lateral sulcus; 2) the right superior parietal lobule and intraparietal sulcus; and, 3) dorsal/ventral regions of the posterior section of the transverse temporal gyrus. HIV status, biological, and cardiovascular disease (CVD) variables were not linked to IIVd -related GM atrophy. Conclusions IIVd in neuropsychological test performance may be a sensitive marker of cortical integrity in older adults, regardless of HIV infection status or CVD risk factors, and degree of intra-individual variability links with volume loss in specific cortical regions; independent of mean-level performance on neuropsychological tests. PMID:26303224

  10. Fusion of a polarized projectile with a polarized target

    International Nuclear Information System (INIS)

    Christley, J.A.; Johnson, R.C.; Thompson, I.J.

    1995-01-01

    The fusion cross sections for a polarized target with both unpolarized and polarized projectiles are studied. Expressions for the observables are given for the case when both nuclei are polarized. Calculations for fusion of an aligned 165 Ho target with 16 O and polarized 7 Li beams are presented

  11. Neuregulin 3 Mediates Cortical Plate Invasion and Laminar Allocation of GABAergic Interneurons

    Directory of Open Access Journals (Sweden)

    Giorgia Bartolini

    2017-01-01

    Full Text Available Neural circuits in the cerebral cortex consist of excitatory pyramidal cells and inhibitory interneurons. These two main classes of cortical neurons follow largely different genetic programs, yet they assemble into highly specialized circuits during development following a very precise choreography. Previous studies have shown that signals produced by pyramidal cells influence the migration of cortical interneurons, but the molecular nature of these factors has remained elusive. Here, we identified Neuregulin 3 (Nrg3 as a chemoattractive factor expressed by developing pyramidal cells that guides the allocation of cortical interneurons in the developing cortical plate. Gain- and loss-of-function approaches reveal that Nrg3 modulates the migration of interneurons into the cortical plate in a process that is dependent on the tyrosine kinase receptor ErbB4. Perturbation of Nrg3 signaling in conditional mutants leads to abnormal lamination of cortical interneurons. Nrg3 is therefore a critical mediator in the assembly of cortical inhibitory circuits.

  12. Cortical correlates of affective syndrome in dementia due to Alzheimer’s disease

    Directory of Open Access Journals (Sweden)

    Thaís T. Hayata

    2015-07-01

    Full Text Available Neuropsychiatric symptoms in Alzheimer’s disease (AD are prevalent, however their relationship with patterns of cortical atrophy is not fully known. Objectives To compare cortical atrophy’s patterns between AD patients and healthy controls; to verify correlations between neuropsychiatric syndromes and cortical atrophy. Method 33 AD patients were examined by Neuropsychiatric Inventory (NPI. Patients and 29 controls underwent a 3T MRI scanning. We considered four NPI syndromes: affective, apathy, hyperactivity and psychosis. Correlations between structural imaging and neuropsychiatric scores were performed by Freesurfer. Results were significant with a p-value < 0.05, corrected for multiple comparisons. Results Patients exhibited atrophy in entorhinal cortices, left inferior and middle temporal gyri, and precuneus bilaterally. There was correlation between affective syndrome and cortical thickness in right frontal structures, insula and temporal pole. Conclusion Cortical thickness measures revealed atrophy in mild AD. Depression and anxiety symptoms were associated with atrophy of right frontal, temporal and insular cortices.

  13. Early development of synchrony in cortical activations in the human.

    Science.gov (United States)

    Koolen, N; Dereymaeker, A; Räsänen, O; Jansen, K; Vervisch, J; Matic, V; Naulaers, G; De Vos, M; Van Huffel, S; Vanhatalo, S

    2016-05-13

    Early intermittent cortical activity is thought to play a crucial role in the growth of neuronal network development, and large scale brain networks are known to provide the basis for higher brain functions. Yet, the early development of the large scale synchrony in cortical activations is unknown. Here, we tested the hypothesis that the early intermittent cortical activations seen in the human scalp EEG show a clear developmental course during the last trimester of pregnancy, the period of intensive growth of cortico-cortical connections. We recorded scalp EEG from altogether 22 premature infants at post-menstrual age between 30 and 44 weeks, and the early cortical synchrony was quantified using recently introduced activation synchrony index (ASI). The developmental correlations of ASI were computed for individual EEG signals as well as anatomically and mathematically defined spatial subgroups. We report two main findings. First, we observed a robust and statistically significant increase in ASI in all cortical areas. Second, there were significant spatial gradients in the synchrony in fronto-occipital and left-to-right directions. These findings provide evidence that early cortical activity is increasingly synchronized across the neocortex. The ASI-based metrics introduced in our work allow direct translational comparison to in vivo animal models, as well as hold promise for implementation as a functional developmental biomarker in future research on human neonates. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  14. Cortical inactivation by cooling in small animals

    Directory of Open Access Journals (Sweden)

    Ben eCoomber

    2011-06-01

    Full Text Available Reversible inactivation of the cortex by surface cooling is a powerful method for studying the function of a particular area. Implanted cooling cryoloops have been used to study the role of individual cortical areas in auditory processing of awake-behaving cats. Cryoloops have also been used in rodents for reversible inactivation of the cortex, but recently there has been a concern that the cryoloop may also cool non-cortical structures either directly or via the perfusion of blood, cooled as it passed close to the cooling loop. In this study we have confirmed that the loop can inactivate most of the auditory cortex without causing a significant reduction in temperature of the auditory thalamus or other sub-cortical structures. We placed a cryoloop on the surface of the guinea pig cortex, cooled it to 2°C and measured thermal gradients across the neocortical surface. We found that the temperature dropped to 20-24°C among cells within a radius of about 2.5mm away from the loop. This temperature drop was sufficient to reduce activity of most cortical cells and led to the inactivation of almost the entire auditory region. When the temperature of thalamus, midbrain, and middle ear were measured directly during cortical cooling, there was a small drop in temperature (about 4°C but this was not sufficient to directly reduce neural activity. In an effort to visualise the extent of neural inactivation we measured the uptake of thallium ions following an intravenous injection. This confirmed that there was a large reduction of activity across much of the ipsilateral cortex and only a small reduction in subcortical structures.

  15. Brain cortical thickness in male adolescents with serious substance use and conduct problems.

    Science.gov (United States)

    Chumachenko, Serhiy Y; Sakai, Joseph T; Dalwani, Manish S; Mikulich-Gilbertson, Susan K; Dunn, Robin; Tanabe, Jody; Young, Susan; McWilliams, Shannon K; Banich, Marie T; Crowley, Thomas J

    2015-01-01

    Adolescents with substance use disorder (SUD) and conduct problems exhibit high levels of impulsivity and poor self-control. Limited work to date tests for brain cortical thickness differences in these youths. To investigate differences in cortical thickness between adolescents with substance use and conduct problems and controls. We recruited 25 male adolescents with SUD, and 19 male adolescent controls, and completed structural 3T magnetic resonance brain imaging. Using the surface-based morphometry software FreeSurfer, we completed region-of-interest (ROI) analyses for group cortical thickness differences in left, and separately right, inferior frontal gyrus (IFG), orbitofrontal cortex (OFC) and insula. Using FreeSurfer, we completed whole-cerebrum analyses of group differences in cortical thickness. Versus controls, the SUD group showed no cortical thickness differences in ROI analyses. Controlling for age and IQ, no regions with cortical thickness differences were found using whole-cerebrum analyses (though secondary analyses co-varying IQ and whole-cerebrum cortical thickness yielded a between-group cortical thickness difference in the left posterior cingulate/precuneus). Secondary findings showed that the SUD group, relative to controls, demonstrated significantly less right > left asymmetry in IFG, had weaker insular-to-whole-cerebrum cortical thickness correlations, and showed a positive association between conduct disorder symptom count and cortical thickness in a superior temporal gyrus cluster. Functional group differences may reflect a more nuanced cortical morphometric difference than ROI cortical thickness. Further investigation of morphometric differences is needed. If replicable findings can be established, they may aid in developing improved diagnostic or more targeted treatment approaches.

  16. The cortical representation of sensory inputs arising from bone.

    Science.gov (United States)

    Ivanusic, Jason J; Sahai, Vineet; Mahns, David A

    2009-05-07

    In the present study, we show that sensory information from bone reaches the discriminative areas of the somatosensory cortices by electrically stimulating the nerve to the cat humerus and recording evoked potentials on the surface of the primary (SI) and secondary (SII) somatosensory cortex. The SI focus was located over the rostral part of the postcruciate cortex, caudal to the lateral aspect of the cruciate sulcus. The SII focus was identified on the anterior ectosylvian gyrus, lateral to the suprasylvian sulcus. These foci were located adjacent to, or within areas that responded to stimulation of the median, ulnar and/or musculocutaneous nerves. The latency (6-11 ms) to onset of cortical responses in SI and SII were indistinguishable (unpaired t-test; P>0.05), and were consistent with activation of A delta fibers in the peripheral nerve. The amplitudes of the cortical responses were graded as a function of stimulus intensity, and may reflect a mechanism for intensity coding. We did not observe long latency cortical responses (50-300 ms) that would be consistent with C fiber activation in the peripheral nerve, and provide evidence that this may be attributable to inhibition of cortical responsiveness following the initial A delta response. Our finding of discrete, short latency evoked potentials (presumably of A delta origin) in the primary and secondary somatosensory cortices, following stimulation of a nerve innervating bone, may reflect a mechanism for the discriminative component of bone pain.

  17. Paradiaphyseal calcific tendinitis with cortical bone erosion.

    Science.gov (United States)

    Fritz, P; Bardin, T; Laredo, J D; Ziza, J M; D'Anglejan, G; Lansaman, J; Bucki, B; Forest, M; Kuntz, D

    1994-05-01

    To determine the clinical, radiologic, and histologic features of calcific tendinitis with cortical bone erosion. The records of 6 patients with paradiaphyseal calcific tendinitis and adjacent bone cortex erosion were reviewed. Calcific tendinitis involved the linea aspera in 4 patients, the bicipital groove in 1 patient, and the deltoid insertion in another. Calcium deposits were associated with cortical bone erosions, revealed on plain radiographs in 4 patients and computed tomography scans in 2. Bone scans were performed in 2 patients and showed local hyperfixation of the isotope. In 4 patients, suspicion of a neoplasm led to a biopsy. Calcium deposits appeared to be surrounded by a foreign body reaction with numerous giant cells. Apatite crystals were identified by transmission electron microscopy and elemental analysis in 1 surgical sample. Paradiaphyseal calcific tendinitis with cortical bone erosion is an uncommon presentation of apatite deposition disease.

  18. Cerebellar Shaping of Motor Cortical Firing Is Correlated with Timing of Motor Actions

    Directory of Open Access Journals (Sweden)

    Abdulraheem Nashef

    2018-05-01

    Full Text Available Summary: In higher mammals, motor timing is considered to be dictated by cerebellar control of motor cortical activity, relayed through the cerebellar-thalamo-cortical (CTC system. Nonetheless, the way cerebellar information is integrated with motor cortical commands and affects their temporal properties remains unclear. To address this issue, we activated the CTC system in primates and found that it efficiently recruits motor cortical cells; however, the cortical response was dominated by prolonged inhibition that imposed a directional activation across the motor cortex. During task performance, cortical cells that integrated CTC information fired synchronous bursts at movement onset. These cells expressed a stronger correlation with reaction time than non-CTC cells. Thus, the excitation-inhibition interplay triggered by the CTC system facilitates transient recruitment of a cortical subnetwork at movement onset. The CTC system may shape neural firing to produce the required profile to initiate movements and thus plays a pivotal role in timing motor actions. : Nashef et al. identified a motor cortical subnetwork recruited by cerebellar volley that was transiently synchronized at movement onset. Cerebellar control of cortical firing was dominated by inhibition that shaped task-related firing of neurons and may dictate motor timing. Keywords: motor control, primates, cerebellar-thalamo-cortical, synchrony, noise correlation, reaction time

  19. [Schizophrenia and cortical GABA neurotransmission].

    Science.gov (United States)

    Hashimoto, Takanori; Matsubara, Takuro; Lewis, David A

    2010-01-01

    -synaptic GABA-A receptors. Our recent analyses demonstrated that this pattern exists across diverse cortical areas including the prefrontal, anterior cingulate, primary motor, and primary visual cortices. GABA neurotransmission by PV-containing and SST-containing neurons is important for the generation of cortical oscillatory activities in the gamma (30-100 Hz) and theta (4-7 Hz) bands, respectively. These oscillatory activities have been proposed to play critical roles in regulating the efficiency of information transfer between neurons and neuronal networks in the cortex. Altered cortical GABA neurotransmission appears to contribute to disturbances in diverse functions through affecting the generation of cortical oscillations in schizophrenia.

  20. Retrosplenial cortical thinning as a possible major contributor for cognitive impairment in HIV patients

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Na-Young [The Catholic University of Korea, Department of Radiology, College of Medicine, Seoul (Korea, Republic of); Hong, Jinwoo; Yoon, Uicheul [Catholic University of Daegu, Department of Biomedical Engineering, College of Health and Medical Science, Gyeongsan-si, Gyeongbuk (Korea, Republic of); Choi, Jun Yong [Yonsei University College of Medicine, Department of Internal Medicine and AIDS Research Institute, Seoul (Korea, Republic of); Lee, Seung-Koo [Yonsei University College of Medicine, Department of Radiology, Seoul (Korea, Republic of); Lim, Soo Mee [Ewha Womans University, School of Medicine, Department of Radiology, Seoul (Korea, Republic of)

    2017-11-15

    To identify brain cortical regions relevant to HIV-associated neurocognitive disorder (HAND) in HIV patients. HIV patients with HAND (n = 10), those with intact cognition (HIV-IC; n = 12), and age-matched, seronegative controls (n = 11) were recruited. All participants were male and underwent 3-dimensional T1-weighted imaging. Both vertex-wise and region of interest (ROI) analyses were performed to analyse cortical thickness. Compared to controls, both HIV-IC and HAND showed decreased cortical thickness mainly in the bilateral primary sensorimotor areas, extending to the prefrontal and parietal cortices. When directly comparing HIV-IC and HAND, HAND showed cortical thinning in the left retrosplenial cortex, left dorsolateral prefrontal cortex, left inferior parietal lobule, bilateral superior medial prefrontal cortices, right temporoparietal junction and left hippocampus, and cortical thickening in the left middle occipital cortex. Left retrosplenial cortical thinning showed significant correlation with slower information processing, declined verbal memory and executive function, and impaired fine motor skills. This study supports previous research suggesting the selective vulnerability of the primary sensorimotor cortices and associations between cortical thinning in the prefrontal and parietal cortices and cognitive impairment in HIV-infected patients. Furthermore, for the first time, we propose retrosplenial cortical thinning as a possible major contributor to HIV-associated cognitive impairment. (orig.)

  1. Retrosplenial cortical thinning as a possible major contributor for cognitive impairment in HIV patients

    International Nuclear Information System (INIS)

    Shin, Na-Young; Hong, Jinwoo; Yoon, Uicheul; Choi, Jun Yong; Lee, Seung-Koo; Lim, Soo Mee

    2017-01-01

    To identify brain cortical regions relevant to HIV-associated neurocognitive disorder (HAND) in HIV patients. HIV patients with HAND (n = 10), those with intact cognition (HIV-IC; n = 12), and age-matched, seronegative controls (n = 11) were recruited. All participants were male and underwent 3-dimensional T1-weighted imaging. Both vertex-wise and region of interest (ROI) analyses were performed to analyse cortical thickness. Compared to controls, both HIV-IC and HAND showed decreased cortical thickness mainly in the bilateral primary sensorimotor areas, extending to the prefrontal and parietal cortices. When directly comparing HIV-IC and HAND, HAND showed cortical thinning in the left retrosplenial cortex, left dorsolateral prefrontal cortex, left inferior parietal lobule, bilateral superior medial prefrontal cortices, right temporoparietal junction and left hippocampus, and cortical thickening in the left middle occipital cortex. Left retrosplenial cortical thinning showed significant correlation with slower information processing, declined verbal memory and executive function, and impaired fine motor skills. This study supports previous research suggesting the selective vulnerability of the primary sensorimotor cortices and associations between cortical thinning in the prefrontal and parietal cortices and cognitive impairment in HIV-infected patients. Furthermore, for the first time, we propose retrosplenial cortical thinning as a possible major contributor to HIV-associated cognitive impairment. (orig.)

  2. The temporal and geographical mercury patterns in polar bears and birds of prey

    DEFF Research Database (Denmark)

    Dietz, R.; Riget, F.; Olsen, M.T.

    2004-01-01

    Mercury compounds are bio-accumulated. As a consequence the highest levels of mercury are measured in top predators like seals, toothed whales, polar bears, and also humans. The main mercury source for humans is the diet but the processes that links emission with effects through the transport chain...... and seals. The coupling between transport pathways of carbon and mercury is weak at lower trophic levels. A substantial decrease of Hg concentrations in teeth and hair of polar bears since 1960 was found. Hg concentrations in hair of polar bears sampled in East Greenland during 1999-2001 was 8.3 times...... a new parameterisation of the removal of atmospheric mercury for Danish Eulerian Hemispheric Model (DEHM) and to validate the model. As a first estimate about 200 tons/year is deposited to the surface north of polar circle. In undisturbed sediment cores the mercury concentration and the mercury...

  3. Atf3 links loss of epithelial polarity to defects in cell differentiation and cytoarchitecture

    Czech Academy of Sciences Publication Activity Database

    Donohoe, C. D.; Csordás, G.; Correia, A.; Jindra, Marek; Klein, C.; Habermann, B.; Uhlířová, M.

    2018-01-01

    Roč. 14, č. 3 (2018), č. článku e1007241. ISSN 1553-7404 R&D Projects: GA MŠk(CZ) LM2015062 Institutional support: RVO:60077344 Keywords : cell polarity * transcriptional regulation * Drosophila Subject RIV: EB - Genetics ; Molecular Biology OBOR OECD: Biochemistry and molecular biology Impact factor: 6.100, year: 2016 http://journals.plos.org/plosgenetics/article?id=10.1371/journal.pgen.1007241

  4. Update of the Polar SWIFT model for polar stratospheric ozone loss (Polar SWIFT version 2)

    Science.gov (United States)

    Wohltmann, Ingo; Lehmann, Ralph; Rex, Markus

    2017-07-01

    The Polar SWIFT model is a fast scheme for calculating the chemistry of stratospheric ozone depletion in polar winter. It is intended for use in global climate models (GCMs) and Earth system models (ESMs) to enable the simulation of mutual interactions between the ozone layer and climate. To date, climate models often use prescribed ozone fields, since a full stratospheric chemistry scheme is computationally very expensive. Polar SWIFT is based on a set of coupled differential equations, which simulate the polar vortex-averaged mixing ratios of the key species involved in polar ozone depletion on a given vertical level. These species are O3, chemically active chlorine (ClOx), HCl, ClONO2 and HNO3. The only external input parameters that drive the model are the fraction of the polar vortex in sunlight and the fraction of the polar vortex below the temperatures necessary for the formation of polar stratospheric clouds. Here, we present an update of the Polar SWIFT model introducing several improvements over the original model formulation. In particular, the model is now trained on vortex-averaged reaction rates of the ATLAS Chemistry and Transport Model, which enables a detailed look at individual processes and an independent validation of the different parameterizations contained in the differential equations. The training of the original Polar SWIFT model was based on fitting complete model runs to satellite observations and did not allow for this. A revised formulation of the system of differential equations is developed, which closely fits vortex-averaged reaction rates from ATLAS that represent the main chemical processes influencing ozone. In addition, a parameterization for the HNO3 change by denitrification is included. The rates of change of the concentrations of the chemical species of the Polar SWIFT model are purely chemical rates of change in the new version, whereas in the original Polar SWIFT model, they included a transport effect caused by the

  5. Time course of transient cortical scintigraphic defects associated with acute pyelonephritis

    Energy Technology Data Exchange (ETDEWEB)

    Ditchfield, Michael R.; Summerville, Dianne; Cook, David J.; Campo, John F. de [Department of Radiology, Royal Children' s Hospital, Melbourne 3052 (Australia); Grimwood, Keith; Nolan, Terrance M. [Department of General Paediatrics, Royal Children' s Hospital, Melbourne (Australia); Department of Paediatrics, University of Melbourne, Melbourne (Australia); Powell, Harley R. [Department of Nephrology, Royal Children' s Hospital, Melbourne (Australia); Sloane, Robert [Department of General Paediatrics, Royal Children' s Hospital, Melbourne (Australia)

    2002-12-01

    Acute pyelonephritis is distinguished from renal scarring using repeat cortical scintigraphy. The defects of acute pyelonephritis resolve, while those of scars persist. To determine the duration of reversible cortical defects following acute pyelonephritis and the time interval required to differentiate infection from scars. Materials and methods. An observational prospective study of 193 children (386 kidneys) aged less than 5 years following their first proven urinary tract infection (UTI). Renal cortical scintigraphic defects were detected in 112 (29%) kidneys within 15 days of diagnosis. Of these, 95 underwent repeat renal cortical scans 2 years after the UTI, including 50 with additional scans performed within 2-6 months of infection. Of the 50 kidneys undergoing a second renal cortical scan within 2-6 months of the first UTI, 22 (44%) had persistent defects. A third scan was performed on 17 (77%) kidneys after 2 years, by which time defects had resolved in another 8 (47%) kidneys. The predictive value of defects detected within 2-6 months of UTI representing scars is 53% (95% CI 28, 77). Overall, nine (18%) kidneys with initial renal cortical abnormalities had permanent defects. In the 45 kidneys undergoing a second cortical scan more than 6 months after the UTI, 11 (24%) had persistent defects. None of the 95 kidneys undergoing serial scans developed new or larger defects. Renal scars may not be reliably diagnosed by cortical scintigraphy performed within 6 months of UTI because the inflammatory lesions may not have fully resolved. (orig.)

  6. Time course of transient cortical scintigraphic defects associated with acute pyelonephritis

    International Nuclear Information System (INIS)

    Ditchfield, Michael R.; Summerville, Dianne; Cook, David J.; Campo, John F. de; Grimwood, Keith; Nolan, Terrance M.; Powell, Harley R.; Sloane, Robert

    2002-01-01

    Acute pyelonephritis is distinguished from renal scarring using repeat cortical scintigraphy. The defects of acute pyelonephritis resolve, while those of scars persist. To determine the duration of reversible cortical defects following acute pyelonephritis and the time interval required to differentiate infection from scars. Materials and methods. An observational prospective study of 193 children (386 kidneys) aged less than 5 years following their first proven urinary tract infection (UTI). Renal cortical scintigraphic defects were detected in 112 (29%) kidneys within 15 days of diagnosis. Of these, 95 underwent repeat renal cortical scans 2 years after the UTI, including 50 with additional scans performed within 2-6 months of infection. Of the 50 kidneys undergoing a second renal cortical scan within 2-6 months of the first UTI, 22 (44%) had persistent defects. A third scan was performed on 17 (77%) kidneys after 2 years, by which time defects had resolved in another 8 (47%) kidneys. The predictive value of defects detected within 2-6 months of UTI representing scars is 53% (95% CI 28, 77). Overall, nine (18%) kidneys with initial renal cortical abnormalities had permanent defects. In the 45 kidneys undergoing a second cortical scan more than 6 months after the UTI, 11 (24%) had persistent defects. None of the 95 kidneys undergoing serial scans developed new or larger defects. Renal scars may not be reliably diagnosed by cortical scintigraphy performed within 6 months of UTI because the inflammatory lesions may not have fully resolved. (orig.)

  7. Effects of SYN1Q555X mutation on cortical gray matter microstructure.

    Science.gov (United States)

    Cabana, Jean-François; Gilbert, Guillaume; Létourneau-Guillon, Laurent; Safi, Dima; Rouleau, Isabelle; Cossette, Patrick; Nguyen, Dang Khoa

    2018-04-19

    A new Q555X mutation on the SYN1 gene was recently found in several members of a family segregating dyslexia, epilepsy, and autism spectrum disorder. To describe the effects of this mutation on cortical gray matter microstructure, we performed a surface-based group study using novel diffusion and quantitative multiparametric imaging on 13 SYN1 Q555X mutation carriers and 13 age- and sex-matched controls. Specifically, diffusion kurtosis imaging (DKI) and neurite orientation and dispersion and density imaging (NODDI) were used to analyze multi-shell diffusion data and obtain parametric maps sensitive to tissue structure, while quantitative metrics sensitive to tissue composition (T1, T2* and relative proton density [PD]) were obtained from a multi-echo variable flip angle FLASH acquisition. Results showed significant microstructural alterations in several regions usually involved in oral and written language as well as dyslexia. The most significant changes in these regions were lowered mean diffusivity and increased fractional anisotropy. This study is, to our knowledge, the first to successfully use diffusion imaging and multiparametric mapping to detect cortical anomalies in a group of subjects with a well-defined genotype linked to language impairments, epilepsy and autism spectrum disorder (ASD). © 2018 Wiley Periodicals, Inc.

  8. Complete mitochondrial genome of a Pleistocene jawbone unveils the origin of polar bear

    Science.gov (United States)

    Lindqvist, Charlotte; Schuster, Stephan C.; Sun, Yazhou; Talbot, Sandra L.; Qi, Ji; Ratan, Aakrosh; Tomsho, Lynn P.; Kasson, Lindsay; Zeyl, Eve; Aars, Jon; Miller, Webb; Ingólfsson, Ólafur; Bachmann, Lutz; Wiig, Øystein

    2010-01-01

    The polar bear has become the flagship species in the climate-change discussion. However, little is known about how past climate impacted its evolution and persistence, given an extremely poor fossil record. Although it is undisputed from analyses of mitochondrial (mt) DNA that polar bears constitute a lineage within the genetic diversity of brown bears, timing estimates of their divergence have differed considerably. Using next-generation sequencing technology, we have generated a complete, high-quality mt genome from a stratigraphically validated 130,000- to 110,000-year-old polar bear jawbone. In addition, six mt genomes were generated of extant polar bears from Alaska and brown bears from the Admiralty and Baranof islands of the Alexander Archipelago of southeastern Alaska and Kodiak Island. We show that the phylogenetic position of the ancient polar bear lies almost directly at the branching point between polar bears and brown bears, elucidating a unique morphologically and molecularly documented fossil link between living mammal species. Molecular dating and stable isotope analyses also show that by very early in their evolutionary history, polar bears were already inhabitants of the Artic sea ice and had adapted very rapidly to their current and unique ecology at the top of the Arctic marine food chain. As such, polar bears provide an excellent example of evolutionary opportunism within a widespread mammalian lineage. PMID:20194737

  9. Complete mitochondrial genome of a Pleistocene jawbone unveils the origin of polar bear.

    Science.gov (United States)

    Lindqvist, Charlotte; Schuster, Stephan C; Sun, Yazhou; Talbot, Sandra L; Qi, Ji; Ratan, Aakrosh; Tomsho, Lynn P; Kasson, Lindsay; Zeyl, Eve; Aars, Jon; Miller, Webb; Ingólfsson, Olafur; Bachmann, Lutz; Wiig, Oystein

    2010-03-16

    The polar bear has become the flagship species in the climate-change discussion. However, little is known about how past climate impacted its evolution and persistence, given an extremely poor fossil record. Although it is undisputed from analyses of mitochondrial (mt) DNA that polar bears constitute a lineage within the genetic diversity of brown bears, timing estimates of their divergence have differed considerably. Using next-generation sequencing technology, we have generated a complete, high-quality mt genome from a stratigraphically validated 130,000- to 110,000-year-old polar bear jawbone. In addition, six mt genomes were generated of extant polar bears from Alaska and brown bears from the Admiralty and Baranof islands of the Alexander Archipelago of southeastern Alaska and Kodiak Island. We show that the phylogenetic position of the ancient polar bear lies almost directly at the branching point between polar bears and brown bears, elucidating a unique morphologically and molecularly documented fossil link between living mammal species. Molecular dating and stable isotope analyses also show that by very early in their evolutionary history, polar bears were already inhabitants of the Artic sea ice and had adapted very rapidly to their current and unique ecology at the top of the Arctic marine food chain. As such, polar bears provide an excellent example of evolutionary opportunism within a widespread mammalian lineage.

  10. Complete mitochondrial genome of a Pleistocene jawbone unveils the origin of polar bear

    Science.gov (United States)

    Lindqvist, Charlotte; Schuster, Stephan C.; Sun, Yazhou; Talbot, Sandra L.; Qi, Ji; Ratan, Aakrosh; Tomsho, Lynn P.; Kasson, Lindsay; Zeyl, Eve; Aars, Jon; Miller, Webb; Ingólfsson, Ólafur; Bachmann, Lutz; Wiig, Øystein

    2010-01-01

    The polar bear has become the flagship species in the climate-change discussion. However, little is known about how past climate impacted its evolution and persistence, given an extremely poor fossil record. Although it is undisputed from analyses of mitochondrial (mt) DNA that polar bears constitute a lineage within the genetic diversity of brown bears, timing estimates of their divergence have differed considerably. Using next-generation sequencing technology, we have generated a complete, high-quality mt genome from a stratigraphically validated 130,000- to 110,000-year-old polar bear jawbone. In addition, six mt genomes were generated of extant polar bears from Alaska and brown bears from the Admiralty and Baranof islands of the Alexander Archipelago of southeastern Alaska and Kodiak Island. We show that the phylogenetic position of the ancient polar bear lies almost directly at the branching point between polar bears and brown bears, elucidating a unique morphologically and molecularly documented fossil link between living mammal species. Molecular dating and stable isotope analyses also show that by very early in their evolutionary history, polar bears were already inhabitants of the Artic sea ice and had adapted very rapidly to their current and unique ecology at the top of the Arctic marine food chain. As such, polar bears provide an excellent example of evolutionary opportunism within a widespread mammalian lineage.

  11. Localization of the kinesin adaptor proteins trafficking kinesin proteins 1 and 2 in primary cultures of hippocampal pyramidal and cortical neurons.

    Science.gov (United States)

    Loss, Omar; Stephenson, F Anne

    2015-07-01

    Neuronal function requires regulated anterograde and retrograde trafficking of mitochondria along microtubules by using the molecular motors kinesin and dynein. Previous work has established that trafficking kinesin proteins (TRAKs),TRAK1 and TRAK2, are kinesin adaptor proteins that link mitochondria to kinesin motor proteins via an acceptor protein in the mitochondrial outer membrane, etc. the Rho GTPase Miro. Recent studies have shown that TRAK1 preferentially controls mitochondrial transport in axons of hippocampal neurons by virtue of its binding to both kinesin and dynein motor proteins, whereas TRAK2 controls mitochondrial transport in dendrites resulting from its binding to dynein. This study further investigates the subcellular localization of TRAK1 and TRAK2 in primary cultures of hippocampal and cortical neurons by using both commercial antibodies and anti-TRAK1 and anti-TRAK2 antibodies raised in our own laboratory (in-house). Whereas TRAK1 was prevalently localized in axons of hippocampal and cortical neurons, TRAK2 was more prevalent in dendrites of hippocampal neurons. In cortical neurons, TRAK2 was equally distributed between axons and dendrites. Some qualitative differences were observed between commercial and in-house-generated antibody immunostaining. © 2015 Wiley Periodicals, Inc.

  12. Quantifying cortical surface harmonic deformation with stereovision during open cranial neurosurgery

    Science.gov (United States)

    Ji, Songbai; Fan, Xiaoyao; Roberts, David W.; Paulsen, Keith D.

    2012-02-01

    Cortical surface harmonic motion during open cranial neurosurgery is well observed in image-guided neurosurgery. Recently, we quantified cortical surface deformation noninvasively with synchronized blood pressure pulsation (BPP) from a sequence of stereo image pairs using optical flow motion tracking. With three subjects, we found the average cortical surface displacement can reach more than 1 mm and in-plane principal strains of up to 7% relative to the first image pair. In addition, the temporal changes in deformation and strain were in concert with BPP and patient respiration [1]. However, because deformation was essentially computed relative to an arbitrary reference, comparing cortical surface deformation at different times was not possible. In this study, we extend the technique developed earlier by establishing a more reliable reference profile of the cortical surface for each sequence of stereo image acquisitions. Specifically, fast Fourier transform (FFT) was applied to the dynamic cortical surface deformation, and the fundamental frequencies corresponding to patient respiration and BPP were identified, which were used to determine the number of image acquisitions for use in averaging cortical surface images. This technique is important because it potentially allows in vivo characterization of soft tissue biomechanical properties using intraoperative stereovision and motion tracking.

  13. Neutron polarization

    International Nuclear Information System (INIS)

    Firk, F.W.K.

    1976-01-01

    Some recent experiments involving polarized neutrons are discussed; they demonstrate how polarization studies provide information on fundamental aspects of nuclear structure that cannot be obtained from more traditional neutron studies. Until recently, neutron polarization studies tended to be limited either to very low energies or to restricted regions at higher energies, determined by the kinematics of favorable (p, vector n) and (d, vector n) reactions. With the advent of high intensity pulsed electron and proton accelerators and of beams of vector polarized deuterons, this is no longer the case. One has entered an era in which neutron polarization experiments are now being carried out, in a routine way, throughout the entire range from thermal energies to tens-of-MeV. The significance of neutron polarization studies is illustrated in discussions of a wide variety of experiments that include the measurement of T-invariance in the β-decay of polarized neutrons, a search for the effects of meson exchange currents in the photo-disintegration of the deuteron, the determination of quantum numbers of states in the fission of aligned 235 U and 237 Np induced by polarized neutrons, and the double- and triple-scattering of fast neutrons by light nuclei

  14. File list: ALL.Neu.50.AllAg.Cortical_neuron [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  15. File list: ALL.Neu.20.AllAg.Cortical_neuron [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  16. File list: ALL.Neu.10.AllAg.Cortical_neuron [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  17. File list: ALL.Neu.05.AllAg.Cortical_neuron [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  18. Classification of Cortical Brain Malformations

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2008-03-01

    Full Text Available Clinical, radiological, and genetic classifications of 113 cases of malformations of cortical development (MCD were evaluated at the Erasmus Medical Center-Sophia Children's Hospital, Rotterdam, the Netherlands.

  19. Predicting the Retention Behavior of Specific O-Linked Glycopeptides.

    Science.gov (United States)

    Badgett, Majors J; Boyes, Barry; Orlando, Ron

    2017-09-01

    O -Linked glycosylation is a common post-translational modification that can alter the overall structure, polarity, and function of proteins. Reverse-phase (RP) chromatography is the most common chromatographic approach to analyze O -glycosylated peptides and their unmodified counterparts, even though this approach often does not provide adequate separation of these two species. Hydrophilic interaction liquid chromatography (HILIC) can be a solution to this problem, as the polar glycan interacts with the polar stationary phase and potentially offers the ability to resolve the peptide from its modified form(s). In this paper, HILIC is used to separate peptides with O - N -acetylgalactosamine ( O -GalNAc), O - N -acetylglucosamine ( O -GlcNAc), and O -fucose additions from their native forms, and coefficients representing the extent of hydrophilicity were derived using linear regression analysis as a means to predict the retention times of peptides with these modifications.

  20. Three-photon polarization ququarts: polarization, entanglement and Schmidt decompositions

    International Nuclear Information System (INIS)

    Fedorov, M V; Miklin, N I

    2015-01-01

    We consider polarization states of three photons, propagating collinearly and having equal given frequencies but with arbitrary distributed horizontal or vertical polarizations of photons. A general form of such states is a superposition of four basic three-photon polarization modes, to be referred to as the three-photon polarization ququarts (TPPQ). All such states can be considered as consisting of one- and two-photon parts, which can be entangled with each other. The degrees of entanglement and polarization, as well as the Schmidt decomposition and Stokes vectors of TPPQ are found and discussed. (paper)

  1. ASYMMETRY OF SOMATOSENSORY CORTICAL PLASTICITY IN PATIENT WITH BILATERAL CARPAL TUNNEL SYNDROME

    Directory of Open Access Journals (Sweden)

    Hikmat Hadoush

    2017-09-01

    Full Text Available Background: Following peripheral nerve lesion, the adult somatosensory system showedcortical reorganizational abilities.Previous studies identified the digits' somatotopy map changes and somatosensory cortical plasticity in response to the Carpal Tunnel Syndrome (CTS that affected the dominant hand only. Objective: Answering the remained question is that what the extent of the cortical plasticity would be in left and right somatosensory cortices in response to CTS affecting the right and left hands simultaneously. Methods: Cortical representations activated by tactile stimulation of median nerve (index and ulnar nerve (little of both dominant and non-dominant hands were evaluated by Magnetoencephalography (MEG systemfor healthy participants and patient with bilateral moderate CTS. index – little fingers'somatotopy map and inter-digit cortical distance was then mapped and calculated for each participant on the real MRI data and the 3D brain surface image. Results: in healthy participants, index – little inter-digit somatosensory cortical distance of right hand (dominant was significantly larger than the index – little inter-digitsomatosensory cortical distance of left hand (11.2±2.1mm vs.7.0±2.9mm, P = 0.006. However, in patient with bilateral CTS, the index – little inter-digit somatosensory cortical distance of righthand (dominant was significantly smaller than the index – little inter-digit somatosensory cortical distance of left hand (5.8mm vs. 7.4mm. Conclusion: our data could be interpreted as the hand use – dependency served more median nerve – cortical territory from the ulnar nerve invasion in the right somatotopy map (left hand than the left somatotopy map of the right hand.

  2. Congenital malformations of the supratentorial brain. Pt. 1. Disorders of cortical development

    International Nuclear Information System (INIS)

    Ertl-Wagner, B.; Rummeny, C.; Reiser, M.F.

    2003-01-01

    Disorders of supratentorial cortical development are usually divided into disorders of neuronal proliferation, neuronal migration and cortical organization. Based upon molecular biologic discoveries, a modified classification has recently been proposed. The category of malformations of abnormal neuronal and glial proliferation and apoptosis now includes microlissencephalies, megalencephalies, hemimegalencephalies and cortical dysplasias with balloon cells. Malformations due to abnormal neuronal migration now subsume the lissencephaly spectrum including the subcortical band heterotopias, the cobblestone complex and the group of heterotopias. Malformations due to abnormal cortical organization include the spectrum of polymicrogyria and schizencephaly as well as cortical dysplasias without balloon cells. High-resolution magnetic resonance imaging (MRI) has led to an increasing awareness of these malformations. This article aims to illustrate the classification, MRI presentation and relevant clinical features of the most commonly encountered disorders of cortical development. (orig.) [de

  3. Nanopatterned bulk metallic glass-based biomaterials modulate macrophage polarization.

    Science.gov (United States)

    Shayan, Mahdis; Padmanabhan, Jagannath; Morris, Aaron H; Cheung, Bettina; Smith, Ryan; Schroers, Jan; Kyriakides, Themis R

    2018-06-01

    Polarization of macrophages by chemical, topographical and mechanical cues presents a robust strategy for designing immunomodulatory biomaterials. Here, we studied the ability of nanopatterned bulk metallic glasses (BMGs), a new class of metallic biomaterials, to modulate murine macrophage polarization. Cytokine/chemokine analysis of IL-4 or IFNγ/LPS-stimulated macrophages showed that the secretion of TNF-α, IL-1α, IL-12, CCL-2 and CXCL1 was significantly reduced after 24-hour culture on BMGs with 55 nm nanorod arrays (BMG-55). Additionally, under these conditions, macrophages increased phagocytic potential and exhibited decreased cell area with multiple actin protrusions. These in vitro findings suggest that nanopatterning can modulate biochemical cues such as IFNγ/LPS. In vivo evaluation of the subcutaneous host response at 2 weeks demonstrated that the ratio of Arg-1 to iNOS increased in macrophages adjacent to BMG-55 implants, suggesting modulation of polarization. In addition, macrophage fusion and fibrous capsule thickness decreased and the number and size of blood vessels increased, which is consistent with changes in macrophage responses. Our study demonstrates that nanopatterning of BMG implants is a promising technique to selectively polarize macrophages to modulate the immune response, and also presents an effective tool to study mechanisms of macrophage polarization and function. Implanted biomaterials elicit a complex series of tissue and cellular responses, termed the foreign body response (FBR), that can be influenced by the polarization state of macrophages. Surface topography can influence polarization, which is broadly characterized as either inflammatory or repair-like. The latter has been linked to improved outcomes of the FBR. However, the impact of topography on macrophage polarization is not fully understood, in part, due to a lack of high moduli biomaterials that can be reproducibly processed at the nanoscale. Here, we studied

  4. Post-adolescent developmental changes in cortical complexity

    OpenAIRE

    Sandu, Anca-Larisa; Izard, Edouard; Specht, Karsten; Beneventi, Harald; Lundervold, Arvid; Ystad, Martin

    2014-01-01

    Background: Post-adolescence is known to be a period of general maturation and development in the human brain. In brain imaging, volumetric and morphologic cortical grey-matter changes can easily be assessed, but the analysis of cortical complexity seems to have been broadly neglected for this age interval. Methods: Magnetic resonance imaging (MRI) was used to acquire structural brain images. The study involved 17 adolescents (mean age 14.1 ± 0.27, 11 girls) who were compared with 1...

  5. Polarization splitter and polarization rotator designs based on transformation optics.

    Science.gov (United States)

    Kwon, Do-Hoon; Werner, Douglas H

    2008-11-10

    The transformation optics technique is employed in this paper to design two optical devices - a two-dimensional polarization splitter and a three-dimensional polarization rotator for propagating beams. The polarization splitter translates the TM- and the TE-polarized components of an incident beam in opposite directions (i.e., shifted up or shifted down). The polarization rotator rotates the polarization state of an incoming beam by an arbitrary angle. Both optical devices are reflectionless at the entry and exit interfaces. Design details and full-wave simulation results are provided.

  6. Real-time dual-polarization transmission based on hybrid optical wireless communications

    Science.gov (United States)

    Sousa, Artur N.; Alimi, Isiaka A.; Ferreira, Ricardo M.; Shahpari, Ali; Lima, Mário; Monteiro, Paulo P.; Teixeira, António L.

    2018-01-01

    We present experimental work on a gigabit-capable and long-reach hybrid coherent UWDM-PON plus FSO system for supporting different applications over the same fiber infrastructure in the mobile backhaul (MBH) networks. Also, for the first time, we demonstrate a reconfigurable real-time DSP transmission/reception of DP-QPSK signals over standard single-mode fiber (SSMF) and FSO links. The receiver presented is based on a commercial field-programmable gate array (FPGA). The considered communication links are based on 20 UDWDM channels with 625 Mbaud and 2.5 GHz channel spacing. We are able to demonstrate the lowest sampling rate required for digital coherent PON by employing four 1.25 Gsa/s ADCs using an electrical front-end receiver that offers only 1 GHz analog bandwidth. We achieved this by implementing a phase and polarization diversity coherent receiver combined with the DP-QPSK modulation formats. The system performance is estimated in terms of receiver sensitivity. The results show the viability of coherent PON and flexible dual-polarization supported by software-defined transceivers for the MBH.

  7. Planar Cell Polarity Breaks the Symmetry of PAR Protein Distribution prior to Mitosis in Drosophila Sensory Organ Precursor Cells.

    Science.gov (United States)

    Besson, Charlotte; Bernard, Fred; Corson, Francis; Rouault, Hervé; Reynaud, Elodie; Keder, Alyona; Mazouni, Khalil; Schweisguth, François

    2015-04-20

    During development, cell-fate diversity can result from the unequal segregation of fate determinants at mitosis. Polarization of the mother cell is essential for asymmetric cell division (ACD). It often involves the formation of a cortical domain containing the PAR complex proteins Par3, Par6, and atypical protein kinase C (aPKC). In the fly notum, sensory organ precursor cells (SOPs) divide asymmetrically within the plane of the epithelium and along the body axis to generate two distinct cells. Fate asymmetry depends on the asymmetric localization of the PAR complex. In the absence of planar cell polarity (PCP), SOPs divide with a random planar orientation but still asymmetrically, showing that PCP is dispensable for PAR asymmetry at mitosis. To study when and how the PAR complex localizes asymmetrically, we have used a quantitative imaging approach to measure the planar polarization of the proteins Bazooka (Baz, fly Par3), Par6, and aPKC in living pupae. By using imaging of functional GFP-tagged proteins with image processing and computational modeling, we find that Baz, Par6, and aPKC become planar polarized prior to mitosis in a manner independent of the AuroraA kinase and that PCP is required for the planar polarization of Baz, Par6, and aPKC during interphase. This indicates that a "mitosis rescue" mechanism establishes asymmetry at mitosis in PCP mutants. This study therefore identifies PCP as the initial symmetry-breaking signal for the planar polarization of PAR proteins in asymmetrically dividing SOPs. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Competing sound sources reveal spatial effects in cortical processing.

    Directory of Open Access Journals (Sweden)

    Ross K Maddox

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

  9. Motor cortical plasticity in Parkinson’s disease

    Directory of Open Access Journals (Sweden)

    Kaviraja eUdupa

    2013-09-01

    Full Text Available In Parkinson’s disease (PD, there are alterations of the basal ganglia (BG thalamo-cortical networks, primarily due to degeneration of nigrostrial dopaminergic neurons. These changes in subcortical networks lead to plastic changes in primary motor cortex (M1, which mediates cortical motor output and is a potential target for treatment of PD. Studies investigating the motor cortical plasticity using non-invasive transcranial magnetic stimulation (TMS have found altered plasticity in PD, but there are inconsistencies among these studies. This is likely because plasticity depends on many factors such as the extent of dopaminergic loss and disease severity, response to dopaminergic replacement therapies, development of L-dopa-induced dyskinesias (LID, the plasticity protocol used, medication and stimulation status in patients treated with deep brain stimulation (DBS. The influences of LID and DBS on BG and M1 plasticity have been explored in animal models and in PD patients. In addition, many other factors such age, genetic factors (e.g. brain derived neurotropic factor and other neurotransmitters or receptors polymorphism, emotional state, time of the day, physical fitness have been documented to play role in the extent of plasticity induced by TMS in human studies. In this review, we summarize the studies that investigated M1 plasticity in PD and demonstrate how these afore-mentioned factors affect motor cortical plasticity in PD. We conclude that it is important to consider the clinical, demographic and technical factors that influence various plasticity protocols while developing these protocols as diagnostic or prognostic tools in PD. We also discuss how the modulation of cortical excitability and the plasticity with these non-invasive brain stimulation techniques facilitate the understanding of the pathophysiology of PD and help design potential therapeutic possibilities in this disorder.

  10. How, when and where can spatial segregation induce opinion polarization? Two competing models

    NARCIS (Netherlands)

    Feliciani, T.; Flache, A.; Tolsma, J.

    2017-01-01

    Increasing ethnic diversity fosters scholarly interest in how the spatial segregation of groups affects opinion polarization in a society. Despite much empirical and theoretical research, there is little consensus in the literature on the causal link between the spatial segregation of two groups and

  11. How, when and where can Spatial Segregation Induce Opinion Polarization? Two Competing Models

    NARCIS (Netherlands)

    Feliciani, Thomas; Flache, Andreas; Tolsma, Jochem

    2017-01-01

    Increasing ethnic diversity fosters scholarly interest in how the spatial segregation of groups affects opinion polarization in a society. Despite much empirical and theoretical research, there is little consensus in the literature on the causal link between the spatial segregation of two groups and

  12. File list: Oth.Neu.10.AllAg.Cortical_neuron [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  13. File list: Oth.Neu.20.AllAg.Cortical_neuron [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  14. File list: Oth.Neu.50.AllAg.Cortical_neuron [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  15. File list: Oth.Neu.05.AllAg.Cortical_neuron [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Neu.05.AllAg.Cortical_neuron mm9 TFs and others Neural Cortical neuron SRX67166...1,SRX1057043 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Oth.Neu.05.AllAg.Cortical_neuron.bed ...

  16. Rapid Identification of Cortical Motor Areas in Rodents by High-Frequency Automatic Cortical Stimulation and Novel Motor Threshold Algorithm

    Directory of Open Access Journals (Sweden)

    Mitsuaki Takemi

    2017-10-01

    Full Text Available Cortical stimulation mapping is a valuable tool to test the functional organization of the motor cortex in both basic neurophysiology (e.g., elucidating the process of motor plasticity and clinical practice (e.g., before resecting brain tumors involving the motor cortex. However, compilation of motor maps based on the motor threshold (MT requires a large number of cortical stimulations and is therefore time consuming. Shortening the time for mapping may reduce stress on the subjects and unveil short-term plasticity mechanisms. In this study, we aimed to establish a cortical stimulation mapping procedure in which the time needed to identify a motor area is reduced to the order of minutes without compromising reliability. We developed an automatic motor mapping system that applies epidural cortical surface stimulations (CSSs through one-by-one of 32 micro-electrocorticographic electrodes while examining the muscles represented in a cortical region. The next stimulus intensity was selected according to previously evoked electromyographic responses in a closed-loop fashion. CSS was repeated at 4 Hz and electromyographic responses were submitted to a newly proposed algorithm estimating the MT with smaller number of stimuli with respect to traditional approaches. The results showed that in all tested rats (n = 12 the motor area maps identified by our novel mapping procedure (novel MT algorithm and 4-Hz CSS significantly correlated with the maps achieved by the conventional MT algorithm with 1-Hz CSS. The reliability of the both mapping methods was very high (intraclass correlation coefficients ≧0.8, while the time needed for the mapping was one-twelfth shorter with the novel method. Furthermore, the motor maps assessed by intracortical microstimulation and the novel CSS mapping procedure in two rats were compared and were also significantly correlated. Our novel mapping procedure that determined a cortical motor area within a few minutes could help

  17. Polarization dynamics and polarization time of random three-dimensional electromagnetic fields

    International Nuclear Information System (INIS)

    Voipio, Timo; Setaelae, Tero; Shevchenko, Andriy; Friberg, Ari T.

    2010-01-01

    We investigate the polarization dynamics of random, stationary three-dimensional (3D) electromagnetic fields. For analyzing the time evolution of the instantaneous polarization state, two intensity-normalized polarization autocorrelation functions are introduced, one based on a geometric approach with the Poincare vectors and the other on energy considerations with the Jones vectors. Both approaches lead to the same conclusions on the rate and strength of the polarization dynamics and enable the definition of a polarization time over which the state of polarization remains essentially unchanged. For fields obeying Gaussian statistics, the two correlation functions are shown to be expressible in terms of quantities characterizing partial 3D polarization and electromagnetic coherence. The 3D degree of polarization is found to have the same meaning in the 3D polarization dynamics as the usual two-dimensional (2D) degree of polarization does with planar fields. The formalism is demonstrated with several examples, and it is expected to be useful in applications dealing with polarization fluctuations of 3D light.

  18. Polarized electron sources

    Energy Technology Data Exchange (ETDEWEB)

    Prepost, R. [Univ. of Wisconsin, Madison, WI (United States)

    1994-12-01

    The fundamentals of polarized electron sources are described with particular application to the Stanford Linear Accelerator Center. The SLAC polarized electron source is based on the principle of polarized photoemission from Gallium Arsenide. Recent developments using epitaxially grown, strained Gallium Arsenide cathodes have made it possible to obtain electron polarization significantly in excess of the conventional 50% polarization limit. The basic principles for Gallium and Arsenide polarized photoemitters are reviewed, and the extension of the basic technique to strained cathode structures is described. Results from laboratory measurements of strained photocathodes as well as operational results from the SLAC polarized source are presented.

  19. Polarized electron sources

    International Nuclear Information System (INIS)

    Prepost, R.

    1994-01-01

    The fundamentals of polarized electron sources are described with particular application to the Stanford Linear Accelerator Center. The SLAC polarized electron source is based on the principle of polarized photoemission from Gallium Arsenide. Recent developments using epitaxially grown, strained Gallium Arsenide cathodes have made it possible to obtain electron polarization significantly in excess of the conventional 50% polarization limit. The basic principles for Gallium and Arsenide polarized photoemitters are reviewed, and the extension of the basic technique to strained cathode structures is described. Results from laboratory measurements of strained photocathodes as well as operational results from the SLAC polarized source are presented

  20. The participation of cortical amygdala in innate, odor-driven behavior

    Science.gov (United States)

    Root, Cory M.; Denny, Christine A.; Hen, René; Axel, Richard

    2014-01-01

    Innate behaviors are observed in naïve animals without prior learning or experience, suggesting that the neural circuits that mediate these behaviors are genetically determined and stereotyped. The neural circuits that convey olfactory information from the sense organ to the cortical and subcortical olfactory centers have been anatomically defined1-3 but the specific pathways responsible for innate responses to volatile odors have not been identified. We have devised genetic strategies that demonstrate that a stereotyped neural circuit that transmits information from the olfactory bulb to cortical amygdala is necessary for innate aversive and appetitive behaviors. Moreover, we have employed the promoter of the activity-dependent gene, arc, to express the photosensitive ion channel, channelrhodopsin, in neurons of the cortical amygdala activated by odors that elicit innate behaviors. Optical activation of these neurons leads to appropriate behaviors that recapitulate the responses to innate odors. These data indicate that the cortical amygdala plays a critical role in the generation of innate odor-driven behaviors but do not preclude the participation of cortical amygdala in learned olfactory behaviors. PMID:25383519

  1. Amygdala activation for eye contact despite complete cortical blindness

    NARCIS (Netherlands)

    Burra, N.; Hervais-Adelman, A.; Kerzel, D.; Tamietto, M.; de Gelder, B.; Pegna, A.J.

    2013-01-01

    Cortical blindness refers to the loss of vision that occurs after destruction of the primary visual cortex. Although there is no sensory cortex and hence no conscious vision, some cortically blind patients show amygdala activation in response to facial or bodily expressions of emotion. Here we

  2. Capacity-Approaching Superposition Coding for Optical Fiber Links

    DEFF Research Database (Denmark)

    Estaran Tolosa, Jose Manuel; Zibar, Darko; Tafur Monroy, Idelfonso

    2014-01-01

    We report on the first experimental demonstration of superposition coded modulation (SCM) for polarization-multiplexed coherent-detection optical fiber links. The proposed coded modulation scheme is combined with phase-shifted bit-to-symbol mapping (PSM) in order to achieve geometric and passive......-SCM) is employed in the framework of bit-interleaved coded modulation with iterative decoding (BICM-ID) for forward error correction. The fiber transmission system is characterized in terms of signal-to-noise ratio for back-to-back case and correlated with simulated results for ideal transmission over additive...... white Gaussian noise channel. Thereafter, successful demodulation and decoding after dispersion-unmanaged transmission over 240-km standard single mode fiber of dual-polarization 6-Gbaud 16-, 32- and 64-ary SCM-PSM is experimentally demonstrated....

  3. Update of the Polar SWIFT model for polar stratospheric ozone loss (Polar SWIFT version 2

    Directory of Open Access Journals (Sweden)

    I. Wohltmann

    2017-07-01

    Full Text Available The Polar SWIFT model is a fast scheme for calculating the chemistry of stratospheric ozone depletion in polar winter. It is intended for use in global climate models (GCMs and Earth system models (ESMs to enable the simulation of mutual interactions between the ozone layer and climate. To date, climate models often use prescribed ozone fields, since a full stratospheric chemistry scheme is computationally very expensive. Polar SWIFT is based on a set of coupled differential equations, which simulate the polar vortex-averaged mixing ratios of the key species involved in polar ozone depletion on a given vertical level. These species are O3, chemically active chlorine (ClOx, HCl, ClONO2 and HNO3. The only external input parameters that drive the model are the fraction of the polar vortex in sunlight and the fraction of the polar vortex below the temperatures necessary for the formation of polar stratospheric clouds. Here, we present an update of the Polar SWIFT model introducing several improvements over the original model formulation. In particular, the model is now trained on vortex-averaged reaction rates of the ATLAS Chemistry and Transport Model, which enables a detailed look at individual processes and an independent validation of the different parameterizations contained in the differential equations. The training of the original Polar SWIFT model was based on fitting complete model runs to satellite observations and did not allow for this. A revised formulation of the system of differential equations is developed, which closely fits vortex-averaged reaction rates from ATLAS that represent the main chemical processes influencing ozone. In addition, a parameterization for the HNO3 change by denitrification is included. The rates of change of the concentrations of the chemical species of the Polar SWIFT model are purely chemical rates of change in the new version, whereas in the original Polar SWIFT model, they included a transport effect

  4. Dose-Dependent Cortical Thinning After Partial Brain Irradiation in High-Grade Glioma

    Energy Technology Data Exchange (ETDEWEB)

    Karunamuni, Roshan [Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, California (United States); Bartsch, Hauke; White, Nathan S. [Department of Radiology, University of California San Diego, La Jolla, California (United States); Moiseenko, Vitali; Carmona, Ruben; Marshall, Deborah C.; Seibert, Tyler M. [Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, California (United States); McDonald, Carrie R. [Department of Psychiatry, University of California San Diego, La Jolla, California (United States); Farid, Nikdokht; Krishnan, Anithapriya; Kuperman, Joshua [Department of Radiology, University of California San Diego, La Jolla, California (United States); Mell, Loren [Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, California (United States); Brewer, James B.; Dale, Anders M. [Department of Radiology, University of California San Diego, La Jolla, California (United States); Hattangadi-Gluth, Jona A., E-mail: jhattangadi@ucsd.edu [Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, California (United States)

    2016-02-01

    Purpose: Radiation-induced cognitive deficits may be mediated by tissue damage to cortical regions. Volumetric changes in cortex can be reliably measured using high-resolution magnetic resonance imaging (MRI). We used these methods to study the association between radiation therapy (RT) dose and change in cortical thickness in high-grade glioma (HGG) patients. Methods and Materials: We performed a voxel-wise analysis of MRI from 15 HGG patients who underwent fractionated partial brain RT. Three-dimensional MRI was acquired pre- and 1 year post RT. Cortex was parceled with well-validated segmentation software. Surgical cavities were censored. Each cortical voxel was assigned a change in cortical thickness between time points, RT dose value, and neuroanatomic label by lobe. Effects of dose, neuroanatomic location, age, and chemotherapy on cortical thickness were tested using linear mixed effects (LME) modeling. Results: Cortical atrophy was seen after 1 year post RT with greater effects at higher doses. Estimates from LME modeling showed that cortical thickness decreased by −0.0033 mm (P<.001) for every 1-Gy increase in RT dose. Temporal and limbic cortex exhibited the largest changes in cortical thickness per Gy compared to that in other regions (P<.001). Age and chemotherapy were not significantly associated with change in cortical thickness. Conclusions: We found dose-dependent thinning of the cerebral cortex, with varying neuroanatomical regional sensitivity, 1 year after fractionated partial brain RT. The magnitude of thinning parallels 1-year atrophy rates seen in neurodegenerative diseases and may contribute to cognitive decline following high-dose RT.

  5. Sensory handedness is not reflected in cortical responses after basic nerve stimulation: a MEG study.

    Science.gov (United States)

    Chen, Andrew C N; Theuvenet, Peter J; de Munck, Jan C; Peters, Maria J; van Ree, Jan M; Lopes da Silva, Fernando L

    2012-04-01

    Motor dominance is well established, but sensory dominance is much less clear. We therefore studied the cortical evoked magnetic fields using magnetoencephalography (MEG) in a group of 20 healthy right handed subjects in order to examine whether standard electrical stimulation of the median and ulnar nerve demonstrated sensory lateralization. The global field power (GFP) curves, as an indication of cortical activation, did not depict sensory lateralization to the dominant left hemisphere. Comparison of the M20, M30, and M70 peak latencies and GFP values exhibited no statistical differences between the hemispheres, indicating no sensory hemispherical dominance at these latencies for each nerve. Field maps at these latencies presented a first and second polarity reversal for both median and ulnar stimulation. Spatial dipole position parameters did not reveal statistical left-right differences at the M20, M30 and M70 peaks for both nerves. Neither did the dipolar strengths at M20, M30 and M70 show a statistical left-right difference for both nerves. Finally, the Laterality Indices of the M20, M30 and M70 strengths did not indicate complete lateralization to one of the hemispheres. After electrical median and ulnar nerve stimulation no evidence was found for sensory hand dominance in brain responses of either hand, as measured by MEG. The results can provide a new assessment of patients with sensory dysfunctions or perceptual distortion when sensory dominance occurs way beyond the estimated norm.

  6. Cortical surface area and cortical thickness in the precuneus of adult humans.

    Science.gov (United States)

    Bruner, E; Román, F J; de la Cuétara, J M; Martin-Loeches, M; Colom, R

    2015-02-12

    The precuneus has received considerable attention in the last decade, because of its cognitive functions, its role as a central node of the brain networks, and its involvement in neurodegenerative processes. Paleoneurological studies suggested that form changes in the deep parietal areas represent a major character associated with the origin of the modern human brain morphology. A recent neuroanatomical survey based on shape analysis suggests that the proportions of the precuneus are also a determinant source of overall brain geometrical differences among adult individuals, influencing the brain spatial organization. Here, we evaluate the variation of cortical thickness and cortical surface area of the precuneus in a sample of adult humans, and their relation with geometry and cognition. Precuneal thickness and surface area are not correlated. There is a marked individual variation. The right precuneus is thinner and larger than the left one, but there are relevant fluctuating asymmetries, with only a modest correlation between the hemispheres. Males have a thicker cortex but differences in cortical area are not significant between sexes. The surface area of the precuneus shows a positive allometry with the brain surface area, although the correlation is modest. The dilation/contraction of the precuneus, described as a major factor of variability within adult humans, is associated with absolute increase/decrease of its surface, but not with variation in thickness. Precuneal thickness, precuneal surface area and precuneal morphology are not correlated with psychological factors such as intelligence, working memory, attention control, and processing speed, stressing further possible roles of this area in supporting default mode functions. Beyond gross morphology, the processes underlying the large phenotypic variation of the precuneus must be further investigated through specific cellular analyses, aimed at considering differences in cellular size, density

  7. Calmodulin immunolocalization to cortical microtubules is calcium independent

    Energy Technology Data Exchange (ETDEWEB)

    Fisher, D.D.; Cyr, R.J.

    1992-12-31

    Calcium affects the stability of cortical microtubules (MTs) in lysed protoplasts. This calmodulin (CaM)-mediated interaction may provide a mechanism that serves to integrate cellular behavior with MT function. To test the hypothesis that CaM associates with these MTs, monoclonal antibodies were produced against CaM, and one (designated mAb1D10), was selected for its suitability as an immunocytochemical reagent. It is shown that CaM associates with the cortical Mats of cultured carrot (Daucus carota L.) and tobacco (Nicotiana tobacum L.) cells. Inasmuch as CaM interacts with calcium and affects the behavior of these Mats, we hypothesized that calcium would alter this association. To test this, protoplasts containing taxol-stabilized Mats were lysed in the presence of various concentrations of calcium and examined for the association of Cam with cortical Mats. At 1 {mu}M calcium, many protoplasts did not have CaM in association with the cortical Mats, while at 3.6 {mu}M calcium, this association was completely abolished. The results are discussed in terms of a model in which CaM associates with Mats via two types of interactions; one calcium dependent and one independent.

  8. Calmodulin immunolocalization to cortical microtubules is calcium independent

    Energy Technology Data Exchange (ETDEWEB)

    Fisher, D.D.; Cyr, R.J.

    1992-01-01

    Calcium affects the stability of cortical microtubules (MTs) in lysed protoplasts. This calmodulin (CaM)-mediated interaction may provide a mechanism that serves to integrate cellular behavior with MT function. To test the hypothesis that CaM associates with these MTs, monoclonal antibodies were produced against CaM, and one (designated mAb1D10), was selected for its suitability as an immunocytochemical reagent. It is shown that CaM associates with the cortical Mats of cultured carrot (Daucus carota L.) and tobacco (Nicotiana tobacum L.) cells. Inasmuch as CaM interacts with calcium and affects the behavior of these Mats, we hypothesized that calcium would alter this association. To test this, protoplasts containing taxol-stabilized Mats were lysed in the presence of various concentrations of calcium and examined for the association of Cam with cortical Mats. At 1 [mu]M calcium, many protoplasts did not have CaM in association with the cortical Mats, while at 3.6 [mu]M calcium, this association was completely abolished. The results are discussed in terms of a model in which CaM associates with Mats via two types of interactions; one calcium dependent and one independent.

  9. Estimation of Melt Pond Fractions on First Year Sea Ice Using Compact Polarization SAR

    Science.gov (United States)

    Li, Haiyan; Perrie, William; Li, Qun; Hou, Yijun

    2017-10-01

    Melt ponds are a common feature on Arctic sea ice. They are linked to the sea ice surface albedo and transmittance of energy to the ocean from the atmosphere and thus constitute an important process to parameterize in Arctic climate models and simulations. This paper presents a first attempt to retrieve the melt pond fraction from hybrid-polarized compact polarization (CP) SAR imagery, which has wider swath and shorter revisit time than the quad-polarization systems, e.g., from RADARSAT-2 (RS-2). The co-polarization (co-pol) ratio has been verified to provide estimates of melt pond fractions. However, it is a challenge to link CP parameters and the co-pol ratio. The theoretical possibility is presented, for making this linkage with the CP parameter C22/C11 (the ratio between the elements of the coherence matrix of CP SAR) for melt pond detection and monitoring with the tilted-Bragg scattering model for the ocean surface. The empirical transformed formulation, denoted as the "compact polarization and quad-pol" ("CPQP") model, is proposed, based on 2062 RS-2 quad-pol SAR images, collocated with in situ measurements. We compared the retrieved melt pond fraction with CP parameters simulated from quad-pol SAR data with results retrieved from the co-pol ratio from quad-pol SAR observations acquired during the Arctic-Ice (Arctic-Ice Covered Ecosystem in a Rapidly Changing Environment) field project. The results are shown to be comparable for observed melt pond measurements in spatial and temporal distributions. Thus, the utility of CP mode SAR for melt pond fraction estimation on first year level ice is presented.

  10. Widespread cortical morphologic changes in juvenile myoclonic epilepsy: evidence from structural MRI.

    LENUS (Irish Health Repository)

    Ronan, Lisa

    2012-04-01

    Atypical morphology of the surface of the cerebral cortex may be related to abnormal cortical folding (gyrification) and therefore may indicate underlying malformations of cortical development (MCDs). Using magnetic resonance imaging (MRI)-based analysis, we examined cortical morphology in patients with juvenile myoclonic epilepsy (JME).

  11. Comparison of skeletal stability after sagittal split ramus osteotomy among mono-cortical plate fixation, bi-cortical plate fixation, and hybrid fixation using absorbable plates and screws.

    Science.gov (United States)

    Ueki, Koichiro; Moroi, Akinori; Yoshizawa, Kunio; Hotta, Asami; Tsutsui, Takamitsu; Fukaya, Kenichi; Hiraide, Ryota; Takayama, Akihiro; Tsunoda, Tatsuta; Saito, Yuki

    2017-02-01

    The purpose of this study was to examine skeletal stability and plate breakage after sagittal split ramus osteotomy (SSRO) with the mono-cortical plate fixation, bi-cortical plate fixation, and hybrid fixation techniques using absorbable plates and screws. A total of 76 Japanese patients diagnosed with mandibular prognathism with and without maxillary deformity were divided into 3 groups randomly. A total of 28 patients underwent SSRO with mono-cortical plate fixation, 23 underwent SSRO with bi-cortical plate fixation, and 25 underwent SSRO with hybrid fixation. Skeletal stability and horizontal condylar angle were analyzed by axial, frontal, and lateral cephalograms from before the operation to 1 year postoperatively. Breakage of the plate and screws was observed by 3-dimensional computed tomography (3DCT) immediately after surgery and after 1 year. Although there was a significant difference between the mono-cortical plate fixation group and hybrid fixation group regarding right MeAg in T1 (P = 0.0488) and occlusal plane in T1 (P = 0.0346), there were no significant differences between the groups for the other measurements in each time interval. In 2 cases, namely, 6 sides in the mono-cortical plate fixation group, breakage of the absorbable plate was found by 3DCT. However, there was no breakage in the bi-cortical plate fixation group and hybrid fixation group. This study results suggested that there were no significant differences in the postoperative skeletal stability among the 3 groups, and bi-cortical fixation as well as hybrid fixation was a reliable and useful method to prevent plate breakage even if an absorbable material was used. Copyright © 2016 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

  12. Extensive cortical rewiring after brain injury.

    Science.gov (United States)

    Dancause, Numa; Barbay, Scott; Frost, Shawn B; Plautz, Erik J; Chen, Daofen; Zoubina, Elena V; Stowe, Ann M; Nudo, Randolph J

    2005-11-02

    Previously, we showed that the ventral premotor cortex (PMv) underwent neurophysiological remodeling after injury to the primary motor cortex (M1). In the present study, we examined cortical connections of PMv after such lesions. The neuroanatomical tract tracer biotinylated dextran amine was injected into the PMv hand area at least 5 months after ischemic injury to the M1 hand area. Comparison of labeling patterns between experimental and control animals demonstrated extensive proliferation of novel PMv terminal fields and the appearance of retrogradely labeled cell bodies within area 1/2 of the primary somatosensory cortex after M1 injury. Furthermore, evidence was found for alterations in the trajectory of PMv intracortical axons near the site of the lesion. The results suggest that M1 injury results in axonal sprouting near the ischemic injury and the establishment of novel connections within a distant target. These results support the hypothesis that, after a cortical injury, such as occurs after stroke, cortical areas distant from the injury undergo major neuroanatomical reorganization. Our results reveal an extraordinary anatomical rewiring capacity in the adult CNS after injury that may potentially play a role in recovery.

  13. Promoting Diversity Through Polar Interdisciplinary Coordinated Education (Polar ICE)

    Science.gov (United States)

    McDonnell, J. D.; Hotaling, L. A.; Garza, C.; Van Dyk, P. B.; Hunter-thomson, K. I.; Middendorf, J.; Daniel, A.; Matsumoto, G. I.; Schofield, O.

    2017-12-01

    Polar Interdisciplinary Coordinated Education (ICE) is an education and outreach program designed to provide public access to the Antarctic and Arctic regions through polar data and interactions with the scientists. The program provides multi-faceted science communication training for early career scientists that consist of a face-to face workshop and opportunities to apply these skills. The key components of the scientist training workshop include cultural competency training, deconstructing/decoding science for non-expert audiences, the art of telling science stories, and networking with members of the education and outreach community and reflecting on communication skills. Scientists partner with educators to provide professional development for K-12 educators and support for student research symposia. Polar ICE has initiated a Polar Literacy initiative that provides both a grounding in big ideas in polar science and science communication training designed to underscore the importance of the Polar Regions to the public while promoting interdisciplinary collaborations between scientists and educators. Our ultimate objective is to promote STEM identity through professional development of scientists and educators while developing career awareness of STEM pathways in Polar science.

  14. Polarization-independent broadband meta-holograms via polarization-dependent nanoholes.

    Science.gov (United States)

    Zhang, Xiaohu; Li, Xiong; Jin, Jinjin; Pu, Mingbo; Ma, Xiaoliang; Luo, Jun; Guo, Yinghui; Wang, Changtao; Luo, Xiangang

    2018-05-17

    Composed of ultrathin metal or dielectric nanostructures, metasurfaces can manipulate the phase, amplitude and polarization of electromagnetic waves at a subwavelength scale, which is promising for flat optical devices. In general, metasurfaces composed of space-variant anisotropic units are sensitive to the incident polarization due to the inherent polarization dependent geometric phase. Here, we implement polarization-independent broadband metasurface holograms constructed by polarization-dependent anisotropic elliptical nanoholes by elaborate design of complex amplitude holograms. The fabricated meta-hologram exhibits a polarization insensitive feature with an acceptable image quality. We verify the feasibility of the design algorithm for three-dimensional (3D) meta-holograms with simulation and the feasibility for two-dimensional (2D) meta-holograms is experimentally demonstrated at a broadband wavelength range from 405 nm to 632.8 nm. The effective polarization-independent broadband complex wavefront control with anisotropic elliptical nanoholes proposed in this paper greatly promotes the practical applications of the metasurface in technologies associated with wavefront manipulation, such as flat lens, colorful holographic displays and optical storage.

  15. The double cortical line: a sign of osteopenia

    International Nuclear Information System (INIS)

    Lamb, C.R.

    1990-01-01

    The double cortical line is a radiographic sign of osteopenia which results from intracortical resorption of bone. This sign is frequently seen in humans with osteopenia but has received minimal attention in the veterinary literature. This report describes the double cortical line in cases of senile osteopenia, nutritional secondary hyperparathyroidism, suspected renal secondary hyperparathyroidism and in the acetabulum following triple pelvic osteotomy for hip dysplasia

  16. APC sets the Wnt tone necessary for cerebral cortical progenitor development.

    Science.gov (United States)

    Nakagawa, Naoki; Li, Jingjun; Yabuno-Nakagawa, Keiko; Eom, Tae-Yeon; Cowles, Martis; Mapp, Tavien; Taylor, Robin; Anton, E S

    2017-08-15

    Adenomatous polyposis coli (APC) regulates the activity of β-catenin, an integral component of Wnt signaling. However, the selective role of the APC-β-catenin pathway in cerebral cortical development is unknown. Here we genetically dissected the relative contributions of APC-regulated β-catenin signaling in cortical progenitor development, a necessary early step in cerebral cortical formation. Radial progenitor-specific inactivation of the APC-β-catenin pathway indicates that the maintenance of appropriate β-catenin-mediated Wnt tone is necessary for the orderly differentiation of cortical progenitors and the resultant formation of the cerebral cortex. APC deletion deregulates β-catenin, leads to high Wnt tone, and disrupts Notch1 signaling and primary cilium maintenance necessary for radial progenitor functions. β-Catenin deregulation directly disrupts cilium maintenance and signaling via Tulp3, essential for intraflagellar transport of ciliary signaling receptors. Surprisingly, deletion of β-catenin or inhibition of β-catenin activity in APC-null progenitors rescues the APC-null phenotype. These results reveal that APC-regulated β-catenin activity in cortical progenitors sets the appropriate Wnt tone necessary for normal cerebral cortical development. © 2017 Nakagawa et al.; Published by Cold Spring Harbor Laboratory Press.

  17. Cortical laminar necrosis in brain infarcts: chronological changes on MRI

    Energy Technology Data Exchange (ETDEWEB)

    Komiyama, M. [Department of Neurosurgery, Osaka City General Hospital, 2-13-22, Miyakojima-Hondouri, Miyakojima, Osaka 534 (Japan); Nishikawa, M. [Department of Neurosurgery, Osaka City General Hospital, 2-13-22, Miyakojima-Hondouri, Miyakojima, Osaka 534 (Japan); Yasui, T. [Department of Neurosurgery, Osaka City General Hospital, 2-13-22, Miyakojima-Hondouri, Miyakojima, Osaka 534 (Japan)

    1997-07-10

    We studied the MRI characteristics of cortical laminar necrosis in ischaemic stroke. We reviewed 13 patients with cortical laminar high signal on T1-weighted images to analyse the chronological changes in signal intensity and contrast enhancement. High-density cortical lesions began to appear on T1-weighted images about 2 weeks after the ictus. At 1-2 months they were prominent. They began to fade from 3 months but could be seen up to 11 months. These cortical lesions showed isointensity or high intensity on T2-weighted images and did not show low intensity at any stage. Contrast enhancement of the laminar lesions was prominent at 1-2 months and became less apparent from 3 months, but could be seen up to 8 months. (orig.). With 6 figs., 1 tab.

  18. File list: Pol.Neu.10.AllAg.Cortical_neuron [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  19. File list: Pol.Neu.20.AllAg.Cortical_neuron [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Pol.Neu.20.AllAg.Cortical_neuron mm9 RNA polymerase Neural Cortical neuron SRX75929...5,SRX759296,SRX217735,SRX759294,SRX759293,SRX217736 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Pol.Neu.20.AllAg.Cortical_neuron.bed ...

  20. File list: Pol.Neu.05.AllAg.Cortical_neuron [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  1. File list: Pol.Neu.50.AllAg.Cortical_neuron [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Pol.Neu.50.AllAg.Cortical_neuron mm9 RNA polymerase Neural Cortical neuron SRX75929...5,SRX759296,SRX759293,SRX759294,SRX217735,SRX217736 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Pol.Neu.50.AllAg.Cortical_neuron.bed ...

  2. Polarization digital holographic microscopy using low-cost liquid crystal polarization rotators

    Science.gov (United States)

    Dovhaliuk, Rostyslav Yu

    2018-02-01

    Polarization imaging methods are actively used to study anisotropic objects. A number of methods and systems, such as imaging polarimeters, were proposed to measure the state of polarization of light that passed through the object. Digital holographic and interferometric approaches can be used to quantitatively measure both amplitude and phase of a wavefront. Using polarization modulation optics, the measurement capabilities of such interference-based systems can be extended to measure polarization-dependent parameters, such as phase retardation. Different kinds of polarization rotators can be used to alternate the polarization of a reference beam. Liquid crystals are used in a rapidly increasing number of different optoelectronic devices. Twisted nematic liquid crystals are widely used as amplitude modulators in electronic displays and light valves or shutter glass. Such devices are of particular interest for polarization imaging, as they can be used as polarization rotators, and due to large-scale manufacturing have relatively low cost. A simple Mach-Zehnder polarized holographic setup that uses modified shutter glass as a polarization rotator is demonstrated. The suggested approach is experimentally validated by measuring retardation of quarter-wave film.

  3. A Surface-based Analysis of Language Lateralization and Cortical Asymmetry

    Science.gov (United States)

    Greve, Douglas N.; Van der Haegen, Lise; Cai, Qing; Stufflebeam, Steven; Sabuncu, Mert R.; Fischl, Bruce; Bysbaert, Marc

    2013-01-01

    Among brain functions, language is one of the most lateralized. Cortical language areas are also some of the most asymmetrical in the brain. An open question is whether the asymmetry in function is linked to the asymmetry in anatomy. To address this question, we measured anatomical asymmetry in 34 participants shown with fMRI to have language dominance of the left hemisphere (LLD) and 21 participants shown to have atypical right hemisphere dominance (RLD). All participants were healthy and left-handed, and most (80%) were female. Gray matter (GM) volume asymmetry was measured using an automated surface-based technique in both ROIs and exploratory analyses. In the ROI analysis, a significant difference between LLD and RLD was found in the insula. No differences were found in planum temporale (PT), pars opercularis (POp), pars triangularis (PTr), or Heschl’s gyrus (HG). The PT, POp, insula, and HG were all significantly left lateralized in both LLD and RLD participants. Both the positive and negative ROI findings replicate a previous study using manually labeled ROIs in a different cohort [Keller, S. S., Roberts, N., Garcia-Finana, M., Mohammadi, S., Ringelstein, E. B., Knecht, S., et al. Can the language-dominant hemisphere be predicted by brain anatomy? Journal of Cognitive Neuroscience, 23, 2013–2029, 2011]. The exploratory analysis was accomplished using a new surface-based registration that aligns cortical folding patterns across both subject and hemisphere. A small but significant cluster was found in the superior temporal gyrus that overlapped with the PT. A cluster was also found in the ventral occipitotemporal cortex corresponding to the visual word recognition area. The surface-based analysis also makes it possible to disentangle the effects of GM volume, thickness, and surface area while removing the effects of curvature. For both the ROI and exploratory analyses, the difference between LLD and RLD volume laterality was most strongly driven by

  4. A Single-Cell Biochemistry Approach Reveals PAR Complex Dynamics during Cell Polarization.

    Science.gov (United States)

    Dickinson, Daniel J; Schwager, Francoise; Pintard, Lionel; Gotta, Monica; Goldstein, Bob

    2017-08-21

    Regulated protein-protein interactions are critical for cell signaling, differentiation, and development. For the study of dynamic regulation of protein interactions in vivo, there is a need for techniques that can yield time-resolved information and probe multiple protein binding partners simultaneously, using small amounts of starting material. Here we describe a single-cell protein interaction assay. Single-cell lysates are generated at defined time points and analyzed using single-molecule pull-down, yielding information about dynamic protein complex regulation in vivo. We established the utility of this approach by studying PAR polarity proteins, which mediate polarization of many animal cell types. We uncovered striking regulation of PAR complex composition and stoichiometry during Caenorhabditis elegans zygote polarization, which takes place in less than 20 min. PAR complex dynamics are linked to the cell cycle by Polo-like kinase 1 and govern the movement of PAR proteins to establish polarity. Our results demonstrate an approach to study dynamic biochemical events in vivo. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. The enemy within: propagation of aberrant corticostriatal learning to cortical function in Parkinson's disease

    Directory of Open Access Journals (Sweden)

    Jeff A Beeler

    2013-09-01

    Full Text Available Motor dysfunction in Parkinson’s disease is believed to arise primarily from pathophysiology in the dorsal striatum and its related corticostriatal and thalamostriatal circuits during progressive dopamine denervation. One function of these circuits is to provide a filter that selectively facilitates or inhibits cortical activity to optimize cortical processing, making motor responses rapid and efficient. Corticostriatal synaptic plasticity mediates the learning that underlies this performance-optimizing filter. Under dopamine denervation, corticostriatal plasticity is altered, resulting in aberrant learning that induces inappropriate basal ganglia filtering that impedes rather than optimizes cortical processing. Human imaging suggests that increased cortical activity may compensate for striatal dysfunction in PD patients. In this Perspective article, we consider how aberrant learning at corticostriatal synapses may impair cortical processing and learning and undermine potential cortical compensatory mechanisms. Blocking or remediating aberrant corticostriatal plasticity may protect cortical function and support cortical compensatory mechanisms mitigating the functional decline associated with progressive dopamine denervation.

  6. Serial MR observation of cortical laminar necrosis caused by brain infarction

    Energy Technology Data Exchange (ETDEWEB)

    Komiyama, M.; Nakajima, H.; Nishikawa, M.; Yasui, T. [Department of Neurosurgery, Osaka City General Hospital (Japan)

    1998-12-01

    To examine the chronological changes characteristic of cortical laminar necrosis caused by brain infarction, 16 patients were repeatedly examined using T1-, T2-weighted spin-echo, T2{sup *}-weighted gradient echo, fluid attenuated inversion recovery (FLAIR) images, and contrast enhanced T1-weighted images at 1.0 or 1.5 T. High intensity cortical lesions were visible on the T1-weighted images from 2 weeks after ictus and became prominent at 1 to 3 months, then became less apparent, but occasionally remained at high intensity for 2 years. High intensity cortical lesions on FLAIR images became prominent from 1 month, and then became less prominent from 1 year, but occasionally remained at high intensity for 2 years. Subcortical lesions did not display high intensity on T1-weighted images at any stage. On FLAIR images, subcortical lesions initially showed slightly high intensity and then low intensity from 6 months due to encephalomalacia. Cortical lesions showed prominent contrast enhancement from 2 weeks to 3 months, but subcortical lesions were prominent from 2 weeks only up to 1 month. T2*-weighted images disclosed haemosiderin in 3 of 7 patients, but there was no correlation with cortical short T1 lesions. Cortical laminar necrosis showed characteristic chronological signal changes on T1-weighted images and FLAIR images. Cortical short T1 lesions were found not to be caused by haemorrhagic infarction. (orig.) With 5 figs., 1 tab., 9 refs.

  7. Polarization holography

    DEFF Research Database (Denmark)

    Nikolova, L.; Ramanujam, P.S.

    Current research into holography is concerned with applications in optically storing, retrieving, and processing information. Polarization holography has many unique properties compared to conventional holography. It gives results in high efficiency, achromaticity, and special polarization...... properties. This books reviews the research carried out in this field over the last 15 years. The authors provide basic concepts in polarization and the propagation of light through anisotropic materials, before presenting a sound theoretical basis for polarization holography. The fabrication...... and characterization of azobenzene based materials, which remain the most efficient for the purpose, is described in detail. This is followed by a description of other materials that are used in polarization holography. An in-depth description of various applications, including display holography and optical storage...

  8. Rehabilitation of cortical blindness secondary to stroke.

    Science.gov (United States)

    Gaber, Tarek A-Z K

    2010-01-01

    Cortical blindness is a rare complication of posterior circulation stroke. However, its complex presentation with sensory, physical, cognitive and behavioural impairments makes it one of the most challenging. Appropriate approach from a rehabilitation standpoint was never reported. Our study aims to discuss the rehabilitation methods and outcomes of a cohort of patients with cortical blindness. The notes of all patients with cortical blindness referred to a local NHS rehabilitation service in the last 6~years were examined. Patients' demographics, presenting symptoms, scan findings, rehabilitation programmes and outcomes were documented. Seven patients presented to our service, six of them were males. The mean age was 63. Patients 1, 2 and 3 had total blindness with severe cognitive and behavioural impairments, wandering and akathisia. All of them failed to respond to any rehabilitation effort and the focus was on damage limitation. Pharmacological interventions had a modest impact on behaviour and sleep pattern. The 3 patients were discharged to a nursing facility. Patients 4, 5, 6 and 7 had partial blindness with variable severity. All of them suffered from significant memory impairment. However, none suffered from any behavioural, physical or other cognitive impairment. Rehabilitation efforts on 3 patients were carried out collaboratively between brain injury occupational therapists and sensory disability officers. All patients experienced significant improvement in handicap and they all maintained community placements. This small cohort of patients suggests that the rehabilitation philosophy and outcomes of these 2 distinct groups of either total or partial cortical blindness differ significantly.

  9. Longitudinal course of cortical thickness decline in amyotrophic lateral sclerosis.

    Science.gov (United States)

    Schuster, Christina; Kasper, Elisabeth; Machts, Judith; Bittner, Daniel; Kaufmann, Jörn; Benecke, Reiner; Teipel, Stefan; Vielhaber, Stefan; Prudlo, Johannes

    2014-10-01

    To determine longitudinal rates of cortical atrophy in classical Amyotrophic lateral sclerosis (ALS) and ALS variants. Rates of cortical thinning were determined between 2 scans, 3-15 months apart, in 77 ALS patients: 51 classical, 12 upper motor neuron (UMN), and 14 lower motor neuron (LMN) ALS variants. Cortical thickness at the first assessment was compared with 60 healthy controls matched by age and gender. Atrophy rates were compared between patient sub-groups and correlated with disease duration, progression, and severity. Using a cross-sectional analysis, we found a significant difference in cortical thickness between ALS patients and controls in the motor and extra-motor areas (left medial orbito frontal gyrus, left inferior parietal gyrus, bilateral insular cortex, right fusiform gyrus, bilateral precuneus). Using a longitudinal analysis, we found a significant decline of cortical thickness in frontal, temporal, and parietal regions over the course of the study in ALS patients. Effects were independent of the clinical subtype, with exception of the precentral gyrus (p gyrus, the UMN-dominant subjects exhibited intermediate rates of atrophy, and the classical ALS patients exhibited no such change. Atrophy of the precentral gyrus in classical ALS indicates a floor effect at the first assessment, resulting in a lack of further atrophy over time. Structural loss of the precentral gyrus appears to be an early sign of classical ALS. Over time, patterns of cortical thinning in extra-motor areas can be identified in ALS, regardless of the phenotype.

  10. Polarized neutron spectrometer

    International Nuclear Information System (INIS)

    Abov, Yu.G.; Novitskij, V.V.; Alfimenkov, V.P.; Galinskij, E.M.; Mareev, Yu.D.; Pikel'ner, L.B.; Chernikov, A.N.; Lason', L.; Tsulaya, V.M.; Tsulaya, M.I.

    2000-01-01

    The polarized neutron spectrometer, intended for studying the interaction of polarized neutrons with nuclei and condensed media in the area of energies from thermal up to several electron-volt, is developed at the IBR-2 reactor (JINR, Dubna). Diffraction on the Co(92%)-Fe(8%) magnetized monocrystals is used for the neutron polarization and polarization analysis. The neutron polarization within the whole energy range equals ∼ 95% [ru

  11. Structural and functional evaluation of cortical motor areas in Amyotrophic Lateral Sclerosis.

    Science.gov (United States)

    Cosottini, Mirco; Pesaresi, Ilaria; Piazza, Selina; Diciotti, Stefano; Cecchi, Paolo; Fabbri, Serena; Carlesi, Cecilia; Mascalchi, Mario; Siciliano, Gabriele

    2012-03-01

    The structural and functional data gathered with Magnetic Resonance Imaging (MRI) techniques about the brain cortical motor damage in Amyotrophic Lateral Sclerosis (ALS) are controversial. In fact some structural MRI studies showed foci of gray matter (GM) atrophy in the precentral gyrus, even in the early stage, while others did not. Most functional MRI (fMRI) studies in ALS reported hyperactivation of extra-primary motor cortices, while contradictory results were obtained on the activation of the primary motor cortex. We aimed to investigate the cortical motor circuitries in ALS patients by a combined structural and functional approach. Twenty patients with definite ALS and 16 healthy subjects underwent a structural examination with acquisition of a 3D T1-weighted sequence and fMRI examination during a maximal force handgrip task executed with the right-hand, the left-hand and with both hands simultaneously. The T1-weighted images were analyzed with Voxel-Based Morphometry (VBM) that showed several clusters of reduced cortical GM in ALS patients compared to controls including the pre and postcentral gyri, the superior, middle and inferior frontal gyri, the supplementary motor area, the superior and inferior parietal cortices and the temporal lobe, bilaterally but more extensive on the right side. In ALS patients a significant hypoactivation of the primary sensory motor cortex and frontal dorsal premotor areas as compared to controls was observed. The hypoactivated areas matched with foci of cortical atrophy demonstrated by VBM. The fMRI analysis also showed an enhanced activation in the ventral premotor frontal areas and in the parietal cortex pertaining to the fronto-parietal motor circuit which paralleled with disease progression rate and matched with cortical regions of atrophy. The hyperactivation of the fronto-parietal circuit was asymmetric and prevalent in the left hemisphere. VBM and fMRI identified structural and functional markers of an extended

  12. Cortical plasticity as a new endpoint measurement for chronic pain

    Directory of Open Access Journals (Sweden)

    Zhuo Min

    2011-07-01

    Full Text Available Abstract Animal models of chronic pain are widely used to investigate basic mechanisms of chronic pain and to evaluate potential novel drugs for treating chronic pain. Among the different criteria used to measure chronic pain, behavioral responses are commonly used as the end point measurements. However, not all chronic pain conditions can be easily measured by behavioral responses such as the headache, phantom pain and pain related to spinal cord injury. Here I propose that cortical indexes, that indicate neuronal plastic changes in pain-related cortical areas, can be used as endpoint measurements for chronic pain. Such cortical indexes are not only useful for those chronic pain conditions where a suitable animal model is lacking, but also serve as additional screening methods for potential drugs to treat chronic pain in humans. These cortical indexes are activity-dependent immediate early genes, electrophysiological identified plastic changes and biochemical assays of signaling proteins. It can be used to evaluate novel analgesic compounds that may act at peripheral or spinal sites. I hope that these new cortical endpoint measurements will facilitate our search for new, and more effective, pain medicines, and help to reduce false lead drug targets.

  13. The maturation of cortical sleep rhythms and networks over early development

    OpenAIRE

    Chu, Catherine Jean; Leahy, J.; Pathmanathan, Jay Sriram; Kramer, M.A.; Cash, Sydney S.

    2014-01-01

    Objective: Although neuronal activity drives all aspects of cortical development, how human brain rhythms spontaneously mature remains an active area of research. We sought to systematically evaluate the emergence of human brain rhythms and functional cortical networks over early development. Methods: We examined cortical rhythms and coupling patterns from birth through adolescence in a large cohort of healthy children (n=384) using scalp electroencephalogram (EEG) in the sleep state. ...

  14. PolarTrack: Optical Outside-In Device Tracking that Exploits Display Polarization

    DEFF Research Database (Denmark)

    Rädle, Roman; Jetter, Hans-Christian; Fischer, Jonathan

    2018-01-01

    PolarTrack is a novel camera-based approach to detecting and tracking mobile devices inside the capture volume. In PolarTrack, a polarization filter continuously rotates in front of an off-the-shelf color camera, which causes the displays of observed devices to periodically blink in the camera feed....... The periodic blinking results from the physical characteristics of current displays, which shine polarized light either through an LC overlay to produce images or through a polarizer to reduce light reflections on OLED displays. PolarTrack runs a simple detection algorithm on the camera feed to segment...... displays and track their locations and orientations, which makes PolarTrack particularly suitable as a tracking system for cross-device interaction with mobile devices. Our evaluation of PolarTrack's tracking quality and comparison with state-of-the-art camera-based multi-device tracking showed a better...

  15. Cerebello-thalamo-cortical networks predict positive symptom progression in individuals at ultra-high risk for psychosis

    Directory of Open Access Journals (Sweden)

    Jessica A. Bernard

    2017-01-01

    Full Text Available Prospective longitudinal evaluation of adolescents at ultra-high-risk (UHR for the development of psychosis enables an enriched neurodevelopmental perspective of disease progression in the absence of many of the factors that typically confound research with formally psychotic patients (antipsychotic medications, drug/alcohol dependence. The cerebellum has been linked to cognitive dysfunction and symptom severity in schizophrenia and recent work from our team suggests that it is a promising target for investigation in UHR individuals as well. However, the cerebellum and cerebello-thalamo-cortical networks have not been investigated developmentally or with respect to disease progression in this critical population. Further, to date, the types of longitudinal multimodal connectivity studies that would substantially inform our understanding of this area have not yet been conducted. In the present investigation 26 UHR and 24 healthy control adolescents were administered structured clinical interviews and scanned at baseline and then again at 12-month time points to investigate both functional and structural connectivity development of cerebello-thalamo-cortical networks in conjunction with symptom progression. Our results provide evidence of abnormal functional and structural cerebellar network development in the UHR group. Crucially, we also found that cerebello-thalamo-cortical network development and connectivity at baseline are associated with positive symptom course, suggesting that cerebellar networks may be a biomarker of disease progression. Together, these findings provide support for neurodevelopmental models of psychotic disorders and suggest that the cerebellum and respective networks with the cortex may be especially important for elucidating the pathophysiology of psychosis and highlighting novel treatment targets.

  16. Rasmussen's encephalitis presenting as focal cortical dysplasia

    Science.gov (United States)

    O'Rourke, D.J.; Bergin, A.; Rotenberg, A.; Peters, J.; Gorman, M.; Poduri, A.; Cryan, J.; Lidov, H.; Madsen, J.; Harini, C.

    2014-01-01

    Rasmussen's encephalitis is a rare syndrome characterized by intractable seizures, often associated with epilepsia partialis continua and symptoms of progressive hemispheric dysfunction. Seizures are usually the hallmark of presentation, but antiepileptic drug treatment fails in most patients and is ineffective against epilepsia partialis continua, which often requires surgical intervention. Co-occurrence of focal cortical dysplasia has only rarely been described and may have implications regarding pathophysiology and management. We describe a rare case of dual pathology of Rasmussen's encephalitis presenting as a focal cortical dysplasia (FCD) and discuss the literature on this topic. PMID:25667877

  17. Calcifying tendinitis of the rotator cuff with cortical bone erosion

    Energy Technology Data Exchange (ETDEWEB)

    Chan, Roxanne; Kim, David H.; Millett, Peter J. [Harvard Medical School, Brigham and Women' s Hospital, Boston, Massachusetts (United States); Weissman, Barbara N. [Harvard Medical School, Brigham and Women' s Hospital, Boston, Massachusetts (United States); Brigham and Women' s Hospital, Department of Radiology, Musculoskeletal Division, Boston (United States)

    2004-10-01

    Calcifying tendinitis occurs most commonly in the rotator cuff tendons, particularly involving the supraspinatus tendon insertion, and is often asymptomatic. Cortical erosion secondary to calcifying tendinitis has been reported in multiple locations, including in the rotator cuff tendons. We present a pathologically proven case of symptomatic calcifying tendinitis involving the infraspinatus tendon with cortical erosion with correlative radiographic, CT, and MR findings. The importance of considering this diagnosis when evaluating lytic lesions of the humerus and the imaging differential diagnosis of calcifying tendinitis and cortical erosion are discussed. (orig.)

  18. Calcifying tendinitis of the rotator cuff with cortical bone erosion

    International Nuclear Information System (INIS)

    Chan, Roxanne; Kim, David H.; Millett, Peter J.; Weissman, Barbara N.

    2004-01-01

    Calcifying tendinitis occurs most commonly in the rotator cuff tendons, particularly involving the supraspinatus tendon insertion, and is often asymptomatic. Cortical erosion secondary to calcifying tendinitis has been reported in multiple locations, including in the rotator cuff tendons. We present a pathologically proven case of symptomatic calcifying tendinitis involving the infraspinatus tendon with cortical erosion with correlative radiographic, CT, and MR findings. The importance of considering this diagnosis when evaluating lytic lesions of the humerus and the imaging differential diagnosis of calcifying tendinitis and cortical erosion are discussed. (orig.)

  19. The continuum of spreading depolarizations in acute cortical lesion development

    DEFF Research Database (Denmark)

    Hartings, Jed A; Shuttleworth, C William; Kirov, Sergei A

    2017-01-01

    A modern understanding of how cerebral cortical lesions develop after acute brain injury is based on Aristides Leão's historic discoveries of spreading depression and asphyxial/anoxic depolarization. Treated as separate entities for decades, we now appreciate that these events define a continuum....... The causal role of these waves in lesion development has been proven by real-time monitoring of electrophysiology, blood flow, and cytotoxic edema. The spreading depolarization continuum further applies to other models of acute cortical lesions, suggesting that it is a universal principle of cortical lesion...

  20. NASA IceBridge and PolarTREC - Education and Outreach Partnership

    Science.gov (United States)

    Bartholow, S.; Warburton, J.; Beck, J.; Woods, J. E.

    2015-12-01

    PolarTREC-Teachers and Researchers Exploring and Collaborating, a teacher professional development program, began with the International Polar Year in 2004 and continues today in the United States. PolarTREC has worked specifically with OIB for 3 years and looking forward to ongoing collaboration. PolarTREC brings U.S. K­12 educators and polar researchers together through an innovative teacher research experience model. Participating teachers spend 3-6 weeks in the field with research teams conducting surveys and collecting data on various aspects of polar science. During their experience, teachers become research team members filling a variety of roles on the team. They also fulfill a unique role of public outreach officer, conducting live presentations about their field site and research as well as journaling, answering questions, and posting photos. Working with OIB has opened up the nature of science for the participating teachers. In developing the long-term relationship with OIB teams, teachers can now share (1) the diversity of training, backgrounds, and interests of OIB scientists, (2) identify the linkages between Greenlandic culture and community and cryospheric science and evidence of climate change, (3) network with Danish and Greenlandic educators on the mission (4) gain access to the full spectrum of a science project - development, implementation, analysis, networking, and dissemination of information. All aspects help these teachers become champions of NASA science and educational leaders in their communities. Evaluation data shows that PolarTREC has clearly achieved it goals with the OIB partnership and suggests that linking teachers and researchers can have the potential to transform the nature of science education. By giving teachers the content knowledge, pedagogical tools, confidence, understanding of science in the broader society, and experiences with scientific inquiry, participating teachers are using authentic scientific research in their

  1. Lunar true polar wander inferred from polar hydrogen.

    Science.gov (United States)

    Siegler, M A; Miller, R S; Keane, J T; Laneuville, M; Paige, D A; Matsuyama, I; Lawrence, D J; Crotts, A; Poston, M J

    2016-03-24

    The earliest dynamic and thermal history of the Moon is not well understood. The hydrogen content of deposits near the lunar poles may yield insight into this history, because these deposits (which are probably composed of water ice) survive only if they remain in permanent shadow. If the orientation of the Moon has changed, then the locations of the shadowed regions will also have changed. The polar hydrogen deposits have been mapped by orbiting neutron spectrometers, and their observed spatial distribution does not match the expected distribution of water ice inferred from present-day lunar temperatures. This finding is in contrast to the distribution of volatiles observed in similar thermal environments at Mercury's poles. Here we show that polar hydrogen preserves evidence that the spin axis of the Moon has shifted: the hydrogen deposits are antipodal and displaced equally from each pole along opposite longitudes. From the direction and magnitude of the inferred reorientation, and from analysis of the moments of inertia of the Moon, we hypothesize that this change in the spin axis, known as true polar wander, was caused by a low-density thermal anomaly beneath the Procellarum region. Radiogenic heating within this region resulted in the bulk of lunar mare volcanism and altered the density structure of the Moon, changing its moments of inertia. This resulted in true polar wander consistent with the observed remnant polar hydrogen. This thermal anomaly still exists and, in part, controls the current orientation of the Moon. The Procellarum region was most geologically active early in lunar history, which implies that polar wander initiated billions of years ago and that a large portion of the measured polar hydrogen is ancient, recording early delivery of water to the inner Solar System. Our hypothesis provides an explanation for the antipodal distribution of lunar polar hydrogen, and connects polar volatiles to the geologic and geophysical evolution of the Moon

  2. Effect of rubber polarity on selective wetting of carbon nanotubes in ternary blends

    Directory of Open Access Journals (Sweden)

    H. H. Le

    2015-11-01

    Full Text Available Based on atomic force microscopy (AFM and Fourier transform infrared spectroscopy (FTIR analysis of the rubber-filler gel (wetting concept the kinetics of selective wetting of carbon nanotubes (CNTs in ternary styrene butadiene rubber (SBR/butadiene rubber (BR/natural rubber (NR blends was qualitatively and quantitatively characterized. Almost all CNTs are found to be wetted by the non-polar NR but not by the other non-polar rubber like BR or weakly polar SBR. It was proposed that phospholipids, which are linked to the α-terminal of NR can interact with the CNT surface through cation-π interactions forming strong bonding between NR and CNTs. Using the corrected surface tension value of NR, which involves the effect of phospholipids found in our previous work the selective wetting of CNTs in ternary rubber blends can be well predicted using the Z-model for a thermodynamic equilibrium state. By replacing the non-polar BR by a polar rubber like nitrile butadiene rubber (NBR as a blend component CNTs are wetted by NBR slightly more than by NR thanks to the strong interaction between CNTs and nitrile groups of NBR. SBR remains unbound to CNTs in both blends.

  3. Cholinergic systems are essential for late-stage maturation and refinement of motor cortical circuits

    Science.gov (United States)

    Ramanathan, Dhakshin S.; Conner, James M.; Anilkumar, Arjun A.

    2014-01-01

    Previous studies reported that early postnatal cholinergic lesions severely perturb early cortical development, impairing neuronal cortical migration and the formation of cortical dendrites and synapses. These severe effects of early postnatal cholinergic lesions preclude our ability to understand the contribution of cholinergic systems to the later-stage maturation of topographic cortical representations. To study cholinergic mechanisms contributing to the later maturation of motor cortical circuits, we first characterized the temporal course of cortical motor map development and maturation in rats. In this study, we focused our attention on the maturation of cortical motor representations after postnatal day 25 (PND 25), a time after neuronal migration has been accomplished and cortical volume has reached adult size. We found significant maturation of cortical motor representations after this time, including both an expansion of forelimb representations in motor cortex and a shift from proximal to distal forelimb representations to an extent unexplainable by simple volume enlargement of the neocortex. Specific cholinergic lesions placed at PND 24 impaired enlargement of distal forelimb representations in particular and markedly reduced the ability to learn skilled motor tasks as adults. These results identify a novel and essential role for cholinergic systems in the late refinement and maturation of cortical circuits. Dysfunctions in this system may constitute a mechanism of late-onset neurodevelopmental disorders such as Rett syndrome and schizophrenia. PMID:25505106

  4. Extracellular Matrix components regulate cellular polarity and tissue structure in the developing and mature Retina

    Directory of Open Access Journals (Sweden)

    Shweta Varshney

    2015-01-01

    Full Text Available While genetic networks and other intrinsic mechanisms regulate much of retinal development, interactions with the extracellular environment shape these networks and modify their output. The present review has focused on the role of one family of extracellular matrix molecules and their signaling pathways in retinal development. In addition to their effects on the developing retina, laminins play a role in maintaining Müller cell polarity and compartmentalization, thereby contributing to retinal homeostasis. This article which is intended for the clinical audience, reviews the fundamentals of retinal development, extracellular matrix organization and the role of laminins in retinal development. The role of laminin in cortical development is also briefly discussed.

  5. Motor cortical plasticity in Parkinson's disease.

    Science.gov (United States)

    Udupa, Kaviraja; Chen, Robert

    2013-09-04

    In Parkinson's disease (PD), there are alterations of the basal ganglia (BG) thalamocortical networks, primarily due to degeneration of nigrostriatal dopaminergic neurons. These changes in subcortical networks lead to plastic changes in primary motor cortex (M1), which mediates cortical motor output and is a potential target for treatment of PD. Studies investigating the motor cortical plasticity using non-invasive transcranial magnetic stimulation (TMS) have found altered plasticity in PD, but there are inconsistencies among these studies. This is likely because plasticity depends on many factors such as the extent of dopaminergic loss and disease severity, response to dopaminergic replacement therapies, development of l-DOPA-induced dyskinesias (LID), the plasticity protocol used, medication, and stimulation status in patients treated with deep brain stimulation (DBS). The influences of LID and DBS on BG and M1 plasticity have been explored in animal models and in PD patients. In addition, many other factors such age, genetic factors (e.g., brain derived neurotropic factor and other neurotransmitters or receptors polymorphism), emotional state, time of the day, physical fitness have been documented to play role in the extent of plasticity induced by TMS in human studies. In this review, we summarize the studies that investigated M1 plasticity in PD and demonstrate how these afore-mentioned factors affect motor cortical plasticity in PD. We conclude that it is important to consider the clinical, demographic, and technical factors that influence various plasticity protocols while developing these protocols as diagnostic or prognostic tools in PD. We also discuss how the modulation of cortical excitability and the plasticity with these non-invasive brain stimulation techniques facilitate the understanding of the pathophysiology of PD and help design potential therapeutic possibilities in this disorder.

  6. A Laminar Organization for Selective Cortico-Cortical Communication

    Directory of Open Access Journals (Sweden)

    Rinaldo D. D’Souza

    2017-08-01

    Full Text Available The neocortex is central to mammalian cognitive ability, playing critical roles in sensory perception, motor skills and executive function. This thin, layered structure comprises distinct, functionally specialized areas that communicate with each other through the axons of pyramidal neurons. For the hundreds of such cortico-cortical pathways to underlie diverse functions, their cellular and synaptic architectures must differ so that they result in distinct computations at the target projection neurons. In what ways do these pathways differ? By originating and terminating in different laminae, and by selectively targeting specific populations of excitatory and inhibitory neurons, these “interareal” pathways can differentially control the timing and strength of synaptic inputs onto individual neurons, resulting in layer-specific computations. Due to the rapid development in transgenic techniques, the mouse has emerged as a powerful mammalian model for understanding the rules by which cortical circuits organize and function. Here we review our understanding of how cortical lamination constrains long-range communication in the mammalian brain, with an emphasis on the mouse visual cortical network. We discuss the laminar architecture underlying interareal communication, the role of neocortical layers in organizing the balance of excitatory and inhibitory actions, and highlight the structure and function of layer 1 in mouse visual cortex.

  7. Polarized proton beams

    International Nuclear Information System (INIS)

    Roser, T.

    1995-01-01

    The acceleration of polarized proton beams in circular accelerators is complicated by the presence of numerous depolarizing spin resonances. Careful and tedious minimization of polarization loss at each of these resonances allowed acceleration of polarized proton beams up to 22 GeV. It has been the hope that Siberian Snakes, which are local spin rotators inserted into ring accelerators, would eliminate these resonances and allow acceleration of polarized beams with the same ease and efficiency that is now routine for unpolarized beams. First tests at IUCF with a full Siberian Snake showed that the spin dynamics with a Snake can be understood in detail. The author now has results of the first tests of a partial Siberian Snake at the AGS, accelerating polarized protons to an energy of about 25 GeV. These successful tests of storage and acceleration of polarized proton beams open up new possibilities such as stored polarized beams for internal target experiments and high energy polarized proton colliders

  8. Cortical Network Dynamics of Perceptual Decision-Making in the Human Brain

    Directory of Open Access Journals (Sweden)

    Markus eSiegel

    2011-02-01

    Full Text Available Goal-directed behavior requires the flexible transformation of sensory evidence about our environment into motor actions. Studies of perceptual decision-making have shown that this transformation is distributed across several widely separated brain regions. Yet, little is known about how decision-making emerges from the dynamic interactions among these regions. Here, we review a series of studies, in which we characterized the cortical network interactions underlying a perceptual decision process in the human brain. We used magnetoencephalography (MEG to measure the large-scale cortical population dynamics underlying each of the sub-processes involved in this decision: the encoding of sensory evidence and action plan, the mapping between the two, and the attentional selection of task-relevant evidence. We found that these sub-processes are mediated by neuronal oscillations within specific frequency ranges. Localized gamma-band oscillations in sensory and motor cortices reflect the encoding of the sensory evidence and motor plan. Large-scale oscillations across widespread cortical networks mediate the integrative processes connecting these local networks: Gamma- and beta-band oscillations across frontal, parietal and sensory cortices serve the selection of relevant sensory evidence and its flexible mapping onto action plans. In sum, our results suggest that perceptual decisions are mediated by oscillatory interactions within overlapping local and large-scale cortical networks.

  9. Adrenal medullary regulation of rat renal cortical adrenergic receptors

    International Nuclear Information System (INIS)

    Sundaresan, P.R.; Guarnaccia, M.M.; Izzo, J.L. Jr.

    1987-01-01

    The role of the adrenal medulla in the regulation of renal cortical adrenergic receptors was investigated in renal cortical particular fractions from control rats and rats 6 wk after adrenal demedullation. The specific binding of [ 3 H]prazosin, [ 3 H]rauwolscine, and [ 125 I]iodocyanopindolol were used to quantitate α 1 -, α 2 -, and β-adrenergic receptors, respectively. Adrenal demedullation increased the concentration of all three groups of renal adrenergic receptors; maximal number of binding sites (B max , per milligram membrane protein) for α 1 -, and α 2 -, and β-adrenergic receptors were increased by 22, 18.5, and 25%, respectively. No differences were found in the equilibrium dissociation constants (K D ) for any of the radioligands. Plasma corticosterone and plasma and renal norepinephrine levels were unchanged, whereas plasma epinephrine was decreased 72% by adrenal demedullation, renal cortical epinephrine was not detectable in control or demedullated animals. The results suggest that, in the physiological state, the adrenal medulla modulates the number of renal cortical adrenergic receptors, presumably through the actions of a circulating factor such as epinephrine

  10. FOCAL CORTICAL DYSPLASIAS: CLINICAL AND ELECTRO-NEUROIMAGING CHARACTERISTICS

    Directory of Open Access Journals (Sweden)

    K. Yu. Mukhin

    2016-01-01

    Full Text Available In spite of a notable advance made in epileptology, resistant epilepsies account for approximately 30 % of all forms of epilepsy particularly in patients with focal seizures. One of the main causes of therapy-resistant focal epilepsies is focal cortical dysplasias (FCD. This term was first introduced by D. Taylor et al. in 1971. FCD belongs to abnormal cortical development. Among all abnormalities of cortical development, FCD in surgically treated children amounts to 75 %. FCD is the most common cause of resistant epilepsy in children and the most frequent reason for diagnosing cryptogenic focal epilepsy with intractable seizures. The author gives a detailed literature review dedicated to FCD as a cause of resistant epilepsy, including the classification and histologic characteristics of FCD, its clinical manifestations and prognosis, and approaches to medical and surgical treatments. 

  11. File list: His.Neu.05.AllAg.Cortical_neuron [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  12. File list: His.Neu.10.AllAg.Cortical_neuron [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  13. File list: His.Neu.50.AllAg.Cortical_neuron [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Neu.50.AllAg.Cortical_neuron mm9 Histone Neural Cortical neuron SRX671649,SRX67...759268,SRX759267,SRX759263,SRX759264,SRX759273,SRX759262,SRX759259,SRX759261,SRX759272 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Neu.50.AllAg.Cortical_neuron.bed ...

  14. File list: His.Neu.20.AllAg.Cortical_neuron [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Neu.20.AllAg.Cortical_neuron mm9 Histone Neural Cortical neuron SRX671649,SRX67...759260,SRX759258,SRX759267,SRX759262,SRX759259,SRX759261,SRX759263,SRX759264,SRX759272 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Neu.20.AllAg.Cortical_neuron.bed ...

  15. Lagrange and Noether analysis of polarization laws of conservation for electromagnetic field

    International Nuclear Information System (INIS)

    Krivskij, I.Yu.; Simulik, V.M.

    1988-01-01

    Both well-known Bessel-Hagen conservation laws and conservation laws of polarized character are derived for electromagnetic field in the Lagrange approach to electrodynamics in terms of intensities (without using the A μ potentials as variation variables). The laws mentioned are derived according to Noether theorem because symmetry to which such concervation laws correspond is lost during the transition from intensities to potentials. Based on Noether theorem (and its generalization for Naeik's symmetries) and Lagrange function scalar in relation to complete Poincare group in terms of intensity tensor, a convenient formula for calculating and values conserved for electromagnetic field is derived which sets up a physically adequate symmetry operator -conservation law correlation and thus links the presence of conservation laws of polarized character with symmetry properties of Maxwell equations. Adiabaticity of conservation laws of polarized character under the presence of interaction with currents and charges is indicated

  16. Cortical heterotopia in Aicardi's syndrome - CT findings

    Energy Technology Data Exchange (ETDEWEB)

    Besenski, N.; Bosnjak, V.; Ligutic, I.; Marusic-Della Marina, B.

    1988-07-01

    The case of 5-month-old female infant with Aicardi's syndrome is presented. The main clinical features were severe developmental retardation and intractable epileptic seizures. Ophthalmoscopic examination revealed pathognomonic choriorethinopathy. Ultrasonic examination of the brain detected agenesis of the corpus callosum, whereas CT showed a coexisting malformation of the brain, i.e. cortical heterotopia of the gray matter. Agenesis of the corpus callosum is an entity well-recognized by sonography. However, ultrasonography is an insufficient modality for the visualization of cortical heterotopia which is common to all cases of Aicardi's syndrome. Therefore, in cases of suspected Aicardi's syndrome CT is recommended, as it enables the diagnosis of cortical heterotopia.

  17. Dysfunctions of the basal ganglia-cerebellar-thalamo-cortical system produce motor tics in Tourette syndrome.

    Science.gov (United States)

    Caligiore, Daniele; Mannella, Francesco; Arbib, Michael A; Baldassarre, Gianluca

    2017-03-01

    Motor tics are a cardinal feature of Tourette syndrome and are traditionally associated with an excess of striatal dopamine in the basal ganglia. Recent evidence increasingly supports a more articulated view where cerebellum and cortex, working closely in concert with basal ganglia, are also involved in tic production. Building on such evidence, this article proposes a computational model of the basal ganglia-cerebellar-thalamo-cortical system to study how motor tics are generated in Tourette syndrome. In particular, the model: (i) reproduces the main results of recent experiments about the involvement of the basal ganglia-cerebellar-thalamo-cortical system in tic generation; (ii) suggests an explanation of the system-level mechanisms underlying motor tic production: in this respect, the model predicts that the interplay between dopaminergic signal and cortical activity contributes to triggering the tic event and that the recently discovered basal ganglia-cerebellar anatomical pathway may support the involvement of the cerebellum in tic production; (iii) furnishes predictions on the amount of tics generated when striatal dopamine increases and when the cortex is externally stimulated. These predictions could be important in identifying new brain target areas for future therapies. Finally, the model represents the first computational attempt to study the role of the recently discovered basal ganglia-cerebellar anatomical links. Studying this non-cortex-mediated basal ganglia-cerebellar interaction could radically change our perspective about how these areas interact with each other and with the cortex. Overall, the model also shows the utility of casting Tourette syndrome within a system-level perspective rather than viewing it as related to the dysfunction of a single brain area.

  18. Dysfunctions of the basal ganglia-cerebellar-thalamo-cortical system produce motor tics in Tourette syndrome.

    Directory of Open Access Journals (Sweden)

    Daniele Caligiore

    2017-03-01

    Full Text Available Motor tics are a cardinal feature of Tourette syndrome and are traditionally associated with an excess of striatal dopamine in the basal ganglia. Recent evidence increasingly supports a more articulated view where cerebellum and cortex, working closely in concert with basal ganglia, are also involved in tic production. Building on such evidence, this article proposes a computational model of the basal ganglia-cerebellar-thalamo-cortical system to study how motor tics are generated in Tourette syndrome. In particular, the model: (i reproduces the main results of recent experiments about the involvement of the basal ganglia-cerebellar-thalamo-cortical system in tic generation; (ii suggests an explanation of the system-level mechanisms underlying motor tic production: in this respect, the model predicts that the interplay between dopaminergic signal and cortical activity contributes to triggering the tic event and that the recently discovered basal ganglia-cerebellar anatomical pathway may support the involvement of the cerebellum in tic production; (iii furnishes predictions on the amount of tics generated when striatal dopamine increases and when the cortex is externally stimulated. These predictions could be important in identifying new brain target areas for future therapies. Finally, the model represents the first computational attempt to study the role of the recently discovered basal ganglia-cerebellar anatomical links. Studying this non-cortex-mediated basal ganglia-cerebellar interaction could radically change our perspective about how these areas interact with each other and with the cortex. Overall, the model also shows the utility of casting Tourette syndrome within a system-level perspective rather than viewing it as related to the dysfunction of a single brain area.

  19. Hyperfixation of Tc-99m ECD in subacute cortical infarction

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae Seung; Kweon, Sun Uck; Ryu, Jin Sook; Moon, Dae Hyuk; Lee, Hee Kyung [College of Medicine, Ulsan Univ., Seoul (Korea, Republic of)

    2001-07-01

    It has been known that hyperfixation of Tc-99m ECD (HF) is not shown in subacute cerebral infarction because the brain distribution of Tc-99m ECD reflects not only perfusion but also the metabolic status of brain tissue. However, we observed several cases with HF in the subacute pure cortical infarction. To find out the cause of HF in subacute cortical infarction. We assessed the difference in associated cerebral hemodynamics and clinical findings between the subacute cortical infarctions with and without HF. We reviewed 16 patients (63.8{+-}8.6 yr, M/F: 15/1) with pure cortical infarction not involving adjacent subcortical white matter on MRI. All patients underwent acetazolamide stress brain perfusion SPECT using Tc-99m ECD and MRI at subacute period (7.3{+-}4.4 days from ictus). Uptake of Tc-99m ECD in infarcted cortex was assessed visually comparing the contralateral side. To assess the difference in associate clinical findings between the infarctions with and without HF, rCVR of the cerebral territory including infarcted cortex, extent of Gd-enhancement on MRI. Intervals between SPECT and ictus, and the presence of associated ICA stenosis were evaluated. Infarctions were focal (n=8) or multifocal (n=8) and located in frontoparietal cortices on MRI. Twelve patients were accompanied with ipsilateral ICA stenosis. Resting SPECT showed increased cortical uptake (=HF) in 7 patients and decreased in 9. rCVR of the MCA territory was preserved in all of the 7 patients with HF, compared with 4 of the 9 patients without HF (p=0.03). Gd-enhancement was minimal in all of the 7 patients with HF, compared with of the 0 patients without HF (p=0.03). Presence of ipsilateral ICA stenosis and intervals from ictus were not different (p>0.1) Subacute cerebral cortical infarction with HF was more frequently associated with preserved rCVR and minimal destruction of the blood-brain barrier than that without HF. Our findings suggest that HF may result from luxury perfusion of

  20. Longitudinal changes in cortical thickness in autism and typical development.

    Science.gov (United States)

    Zielinski, Brandon A; Prigge, Molly B D; Nielsen, Jared A; Froehlich, Alyson L; Abildskov, Tracy J; Anderson, Jeffrey S; Fletcher, P Thomas; Zygmunt, Kristen M; Travers, Brittany G; Lange, Nicholas; Alexander, Andrew L; Bigler, Erin D; Lainhart, Janet E

    2014-06-01

    The natural history of brain growth in autism spectrum disorders remains unclear. Cross-sectional studies have identified regional abnormalities in brain volume and cortical thickness in autism, although substantial discrepancies have been reported. Preliminary longitudinal studies using two time points and small samples have identified specific regional differences in cortical thickness in the disorder. To clarify age-related trajectories of cortical development, we examined longitudinal changes in cortical thickness within a large mixed cross-sectional and longitudinal sample of autistic subjects and age- and gender-matched typically developing controls. Three hundred and forty-five magnetic resonance imaging scans were examined from 97 males with autism (mean age = 16.8 years; range 3-36 years) and 60 males with typical development (mean age = 18 years; range 4-39 years), with an average interscan interval of 2.6 years. FreeSurfer image analysis software was used to parcellate the cortex into 34 regions of interest per hemisphere and to calculate mean cortical thickness for each region. Longitudinal linear mixed effects models were used to further characterize these findings and identify regions with between-group differences in longitudinal age-related trajectories. Using mean age at time of first scan as a reference (15 years), differences were observed in bilateral inferior frontal gyrus, pars opercularis and pars triangularis, right caudal middle frontal and left rostral middle frontal regions, and left frontal pole. However, group differences in cortical thickness varied by developmental stage, and were influenced by IQ. Differences in age-related trajectories emerged in bilateral parietal and occipital regions (postcentral gyrus, cuneus, lingual gyrus, pericalcarine cortex), left frontal regions (pars opercularis, rostral middle frontal and frontal pole), left supramarginal gyrus, and right transverse temporal gyrus, superior parietal lobule, and

  1. Prospective detection of cortical dysplasia on clinical MRI in pediatric intractable epilepsy

    Energy Technology Data Exchange (ETDEWEB)

    Radhakrishnan, Rupa; Leach, James L.; Gelfand, Michael J. [Cincinnati Children' s Hospital Medical Center, Department of Radiology, Cincinnati, OH (United States); Mangano, Francesco T. [Cincinnati Children' s Hospital Medical Center, Department of Neurosurgery, Cincinnati, OH (United States); Rozhkov, Leonid; Greiner, Hansel M. [Cincinnati Children' s Hospital Medical Center, Department of Neurology, Comprehensive Epilepsy Treatment Center, Cincinnati, OH (United States); Miles, Lili [Cincinnati Children' s Hospital Medical Center, Department of Pathology, Cincinnati, OH (United States)

    2016-09-15

    Cortical dysplasia is the most common cause of pediatric refractory epilepsy. MRI detection of epileptogenic lesion is associated with good postsurgical outcome. Additional electrophysiological information is suggested to be helpful in localization of cortical dysplasia. Educational measures were taken to increase the awareness of cortical dysplasia at our institution in the context of a recent International League Against Epilepsy (ILAE 2011) classification of cortical dysplasia. To determine changes in the rate of prospective identification of cortical dysplasia on an initial radiology report and also evaluate the benefit of MRI review as part of a multidisciplinary epilepsy conference in identifying previously overlooked MRI findings. We retrospectively evaluated surgically treated children with refractory epilepsy from 2007 to 2014 with cortical dysplasia on histopathology. We analyzed the initial radiology report, preoperative MRI interpretation at multidisciplinary epilepsy conference and subsequent retrospective MRI review with knowledge of the resection site. We recorded additional electrophysiological data and the presence of lobar concordance with the MRI findings. Of 78 children (44 MRI lesional) evaluated, 18 had initially overlooked MRI findings. Comparing 2007-2010 to 2011-2014, there was improvement in the rate of overlooked findings on the initial radiology report (54% vs. 13% of lesional cases, respectively; P = 0.008). The majority (72%) were identified at a multidisciplinary conference with lobar concordance of findings with at least one additional electrophysiological investigation in 89%. Awareness of current classification schemes of cortical dysplasia and image review in the context of a multidisciplinary conference can lead to improved MRI detection of cortical dysplasia in children. (orig.)

  2. Prospective detection of cortical dysplasia on clinical MRI in pediatric intractable epilepsy

    International Nuclear Information System (INIS)

    Radhakrishnan, Rupa; Leach, James L.; Gelfand, Michael J.; Mangano, Francesco T.; Rozhkov, Leonid; Greiner, Hansel M.; Miles, Lili

    2016-01-01

    Cortical dysplasia is the most common cause of pediatric refractory epilepsy. MRI detection of epileptogenic lesion is associated with good postsurgical outcome. Additional electrophysiological information is suggested to be helpful in localization of cortical dysplasia. Educational measures were taken to increase the awareness of cortical dysplasia at our institution in the context of a recent International League Against Epilepsy (ILAE 2011) classification of cortical dysplasia. To determine changes in the rate of prospective identification of cortical dysplasia on an initial radiology report and also evaluate the benefit of MRI review as part of a multidisciplinary epilepsy conference in identifying previously overlooked MRI findings. We retrospectively evaluated surgically treated children with refractory epilepsy from 2007 to 2014 with cortical dysplasia on histopathology. We analyzed the initial radiology report, preoperative MRI interpretation at multidisciplinary epilepsy conference and subsequent retrospective MRI review with knowledge of the resection site. We recorded additional electrophysiological data and the presence of lobar concordance with the MRI findings. Of 78 children (44 MRI lesional) evaluated, 18 had initially overlooked MRI findings. Comparing 2007-2010 to 2011-2014, there was improvement in the rate of overlooked findings on the initial radiology report (54% vs. 13% of lesional cases, respectively; P = 0.008). The majority (72%) were identified at a multidisciplinary conference with lobar concordance of findings with at least one additional electrophysiological investigation in 89%. Awareness of current classification schemes of cortical dysplasia and image review in the context of a multidisciplinary conference can lead to improved MRI detection of cortical dysplasia in children. (orig.)

  3. Coherence analysis differentiates between cortical myoclonic tremor and essential tremor

    NARCIS (Netherlands)

    van Rootselaar, AF; Maurits, NM; Koelman, JHTM; van der Hoeven, JH; Bour, LJ; Leenders, KL; Brown, P; Tijssen, MAJ

    Familial cortical myoclonic tremor with epilepsy (FCMTE) is characterized by a distal kinetic tremor, infrequent epileptic attacks, and autosomal dominant inheritance. The tremor is thought to originate from the motor cortex. In our patient group, a premovement cortical spike Could not be

  4. SPECT in patients with cortical visual loss.

    Science.gov (United States)

    Silverman, I E; Galetta, S L; Gray, L G; Moster, M; Atlas, S W; Maurer, A H; Alavi, A

    1993-09-01

    Single-photon emission computed tomography (SPECT) with 99mTc-hexamethylpropyleneamine oxime (HMPAO) was used to investigate changes in cerebral blood flow in seven patients with cortical visual impairment. Traumatic brain injury (TBI) was the cause of cortical damage in two patients, cerebral ischemia in two patients and carbon monoxide (CO) poisoning, status epilepticus and Alzheimer's Disease (AD) each in three separate patients. The SPECT scans of the seven patients were compared to T2-weighted magnetic resonance image (MRI) scans of the brain to determine the correlation between functional and anatomical findings. In six of the seven patients, the qualitative interpretation of the SPECT studies supported the clinical findings (i.e., the visual field defect) by revealing altered regional cerebral blood flow (rCBF) in the appropriate regions of the visual pathway. MR scans in all of the patients, on the other hand, were either normal or disclosed smaller lesions than those detected by SPECT. We conclude that SPECT may reveal altered rCBF in patients with cortical visual impairment of various etiologies, even when MRI studies are normal or nondiagnostic.

  5. Probabilistic Coexistence and Throughput of Cognitive Dual-Polarized Networks

    Directory of Open Access Journals (Sweden)

    J.-M. Dricot

    2010-01-01

    Full Text Available Diversity techniques for cognitive radio networks are important since they enable the primary and secondary terminals to efficiently share the spectral resources in the same location simultaneously. In this paper, we investigate a simple, yet powerful, diversity scheme by exploiting the polarimetric dimension. More precisely, we evaluate a scenario where the cognitive terminals use cross-polarized communications with respect to the primary users. Our approach is network-centric, that is, the performance of the proposed dual-polarized system is investigated in terms of link throughput in the primary and the secondary networks. In order to carry out this analysis, we impose a probabilistic coexistence constraint derived from an information-theoretic approach, that is, we enforce a guaranteed capacity for a primary terminal for a high fraction of time. Improvements brought about by the use of our scheme are demonstrated analytically and through simulations. In particular, the main simulation parameters are extracted from a measurement campaign dedicated to the characterization of indoor-to-indoor and outdoor-to-indoor polarization behaviors. Our results suggest that the polarimetric dimension represents a remarkable opportunity, yet easily implementable, in the context of cognitive radio networks.

  6. Cytosolic Pellino-1-Mediated K63-Linked Ubiquitination of IRF5 in M1 Macrophages Regulates Glucose Intolerance in Obesity

    Directory of Open Access Journals (Sweden)

    Donghyun Kim

    2017-07-01

    Full Text Available IRF5 is a signature transcription factor that induces M1 macrophage polarization. However, little is known regarding cytosolic proteins that induce IRF5 activation for M1 polarization. Here, we report the interaction between ubiquitin E3 ligase Pellino-1 and IRF5 in the cytoplasm, which increased nuclear translocation of IRF5 by K63-linked ubiquitination in human and mouse M1 macrophages. LPS and/or IFN-γ increased Pellino-1 expression, and M1 polarization was attenuated in Pellino-1-deficient macrophages in vitro and in vivo. Defective M1 polarization in Pellino-1-deficient macrophages improved glucose intolerance in mice fed a high-fat diet. Furthermore, macrophages in adipose tissues from obese humans exhibited increased Pellino-1 expression and IRF5 nuclear translocation compared with nonobese subjects, and these changes are associated with insulin resistance index. This study demonstrates that cytosolic Pellino-1-mediated K63-linked ubiquitination of IRF5 in M1 macrophages regulates glucose intolerance in obesity, suggesting a cytosolic mediator function of Pellino-1 in TLR4/IFN-γ receptor-IRF5 axis during M1 polarization.

  7. Differential Motor and Prefrontal Cerebello-Cortical Network Development: Evidence from Multimodal Neuroimaging

    Science.gov (United States)

    Bernard, Jessica A.; Orr, Joseph M.; Mittal, Vijay A.

    2015-01-01

    While our understanding of cerebellar structural development through adolescence and young adulthood has expanded, we still lack knowledge of the developmental patterns of cerebellar networks during this critical portion of the lifespan. Volume in lateral posterior cerebellar regions associated with cognition and the prefrontal cortex develops more slowly, reaching their peak volume in adulthood, particularly as compared to motor Lobule V. We predicted that resting state functional connectivity of the lateral posterior regions would show a similar pattern of development during adolescence and young adulthood. That is, we expected to see changes over time in Crus I and Crus II connectivity with the cortex, but no changes in Lobule V connectivity. Additionally, we were interested in how structural connectivity changes in cerebello-thalamo-cortical white matter are related to changes in functional connectivity. A sample of 23 individuals between 12 and 21 years old underwent neuroimaging scans at baseline and 12-months later. Functional networks of Crus I and Crus II showed significant connectivity decreases over 12-months, though there were no differences in Lobule V. Furthermore, these functional connectivity changes were correlated with increases in white matter structural integrity in the corresponding cerebello-thalamo-cortical white matter tract. We suggest that these functional network changes are due to both later pruning in the prefrontal cortex as well as further development of the white matter tracts linking these brain regions. PMID:26391125

  8. Neural correlates of mirth and laughter: a direct electrical cortical stimulation study.

    Science.gov (United States)

    Yamao, Yukihiro; Matsumoto, Riki; Kunieda, Takeharu; Shibata, Sumiya; Shimotake, Akihiro; Kikuchi, Takayuki; Satow, Takeshi; Mikuni, Nobuhiro; Fukuyama, Hidenao; Ikeda, Akio; Miyamoto, Susumu

    2015-05-01

    Laughter consists of both motor and emotional aspects. The emotional component, known as mirth, is usually associated with the motor component, namely, bilateral facial movements. Previous electrical cortical stimulation (ES) studies revealed that mirth was associated with the basal temporal cortex, inferior frontal cortex, and medial frontal cortex. Functional neuroimaging implicated a role for the left inferior frontal and bilateral temporal cortices in humor processing. However, the neural origins and pathways linking mirth with facial movements are still unclear. We hereby report two cases with temporal lobe epilepsy undergoing subdural electrode implantation in whom ES of the left basal temporal cortex elicited both mirth and laughter-related facial muscle movements. In one case with normal hippocampus, high-frequency ES consistently caused contralateral facial movement, followed by bilateral facial movements with mirth. In contrast, in another case with hippocampal sclerosis (HS), ES elicited only mirth at low intensity and short duration, and eventually laughter at higher intensity and longer duration. In both cases, the basal temporal language area (BTLA) was located within or adjacent to the cortex where ES produced mirth. In conclusion, the present direct ES study demonstrated that 1) mirth had a close relationship with language function, 2) intact mesial temporal structures were actively engaged in the beginning of facial movements associated with mirth, and 3) these emotion-related facial movements had contralateral dominance. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Spectrotemporal dynamics of auditory cortical synaptic receptive field plasticity.

    Science.gov (United States)

    Froemke, Robert C; Martins, Ana Raquel O

    2011-09-01

    The nervous system must dynamically represent sensory information in order for animals to perceive and operate within a complex, changing environment. Receptive field plasticity in the auditory cortex allows cortical networks to organize around salient features of the sensory environment during postnatal development, and then subsequently refine these representations depending on behavioral context later in life. Here we review the major features of auditory cortical receptive field plasticity in young and adult animals, focusing on modifications to frequency tuning of synaptic inputs. Alteration in the patterns of acoustic input, including sensory deprivation and tonal exposure, leads to rapid adjustments of excitatory and inhibitory strengths that collectively determine the suprathreshold tuning curves of cortical neurons. Long-term cortical plasticity also requires co-activation of subcortical neuromodulatory control nuclei such as the cholinergic nucleus basalis, particularly in adults. Regardless of developmental stage, regulation of inhibition seems to be a general mechanism by which changes in sensory experience and neuromodulatory state can remodel cortical receptive fields. We discuss recent findings suggesting that the microdynamics of synaptic receptive field plasticity unfold as a multi-phase set of distinct phenomena, initiated by disrupting the balance between excitation and inhibition, and eventually leading to wide-scale changes to many synapses throughout the cortex. These changes are coordinated to enhance the representations of newly-significant stimuli, possibly for improved signal processing and language learning in humans. Copyright © 2011 Elsevier B.V. All rights reserved.

  10. Characterization of the Relationship of CDKL5 with MeCP2 and Dnmt1 in PrimaryRat Cortical Neurons

    Directory of Open Access Journals (Sweden)

    Zhi Yi

    Full Text Available ABSTRACT Cyclin-dependent kinase-like 5 (CDKL5 is a protein kinase that is homologous to mitogen-activated protein kinases (MAPKs and cyclin-dependent kinases (CDKs. Mutations in the CDKL5 gene cause X-linked infantile spasms and phenotypes that overlap with that of Rett syndrome, which is a neurodevelopmental disorder caused primarily by mutations in the methyl CpG binding protein 2 gene (MECP2. Previous studies in transfected cell lines showed that CDKL5 interacts with MeCP2 and DNA (cytosine-5-methyltransferase 1 (Dnmt1. However, little is known about the relationships of CDKL5 with interacting proteins in primary neuronal cultures. In this study, we investigated the expression patterns of CDKL5, MeCP2 and Dnmt1, and their interaction in cultured rat cortical neurons. Using real-time PCR analysis, we found that CDKL5, MeCP2 and Dnmt1 have similar expression patterns at the mRNA level. In contrast, the expression patterns of those proteins at the protein level are different and could be inversely correlated, as shown by western blotting. Using co-immunoprecipitation, we further demonstrated that CDKL5 interacts with MeCP2 and Dnmt1 in primary rat cortical neurons. These data suggest that a functional link exists among CDKL5, MeCP2 and Dnmt1 during neuronal development and may provide further insight into the pathogenesis of Rett syndrome.

  11. File list: InP.Neu.05.AllAg.Cortical_neuron [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  12. File list: InP.Neu.10.AllAg.Cortical_neuron [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  13. File list: InP.Neu.20.AllAg.Cortical_neuron [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  14. File list: InP.Neu.50.AllAg.Cortical_neuron [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Neu.50.AllAg.Cortical_neuron mm9 Input control Neural Cortical neuron SRX804268...76,SRX671651,SRX671655 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/InP.Neu.50.AllAg.Cortical_neuron.bed ...

  15. Organohalogen concentrations and a gross and histologic assessment of multiple organ systems in East Greenland polar bears (Ursus maritimus)

    DEFF Research Database (Denmark)

    Sonne, C.

    To investigate the relation between biological parameters, not earlier investigated in the polar bear, and organohalogen pollution in East Greenland polar bears, we initiated a sampling of adipose tissue, internal organs and skulls from more than 100 free-ranging polar bears killed by local...... in the adipose tissue and pathological changes in skulls and internal organs. Our results suggested a decrease in adipose tissue concentrations of organohalogens in East Greenland polar bears from 1990 to 1999-2001. Two of the biological effect parameters (FA and enlarged clitoris) did not indicate a link......, infectious agents, season and meaby chronic exposure to organohalogens. These result fill out an existing knowledge gap in potential effects of environmental, organic contaminants on fluctuating asymmetry, bone mineral density and functional anatomy (histology) in the polar bear. In addition, the results may...

  16. Charge transport in non-polar and semi-polar III-V nitride heterostructures

    International Nuclear Information System (INIS)

    Konar, Aniruddha; Verma, Amit; Fang, Tian; Zhao, Pei; Jana, Raj; Jena, Debdeep

    2012-01-01

    Compared to the intense research focus on the optical properties, the transport properties in non-polar and semi-polar III-nitride semiconductors remain relatively unexplored to date. The purpose of this paper is to discuss charge-transport properties in non-polar and semi-polar orientations of GaN in a comparative fashion to what is known for transport in polar orientations. A comprehensive approach is adopted, starting from an investigation of the differences in the electronic bandstructure along different polar orientations of GaN. The polarization fields along various orientations are then discussed, followed by the low-field electron and hole mobilities. A number of scattering mechanisms that are specific to non-polar and semi-polar GaN heterostructures are identified, and their effects are evaluated. Many of these scattering mechanisms originate due to the coupling of polarization with disorder and defects in various incarnations depending on the crystal orientation. The effect of polarization orientation on carrier injection into quantum-well light-emitting diodes is discussed. This paper ends with a discussion of orientation-dependent high-field charge-transport properties including velocity saturation, instabilities and tunneling transport. Possible open problems and opportunities are also discussed. (paper)

  17. Neurodevelopmental origins of abnormal cortical morphology in dissociative identity disorder.

    Science.gov (United States)

    Reinders, A A T S; Chalavi, S; Schlumpf, Y R; Vissia, E M; Nijenhuis, E R S; Jäncke, L; Veltman, D J; Ecker, C

    2018-02-01

    To examine the two constitutes of cortical volume (CV), that is, cortical thickness (CT) and surface area (SA), in individuals with dissociative identity disorder (DID) with the view of gaining important novel insights into the underlying neurobiological mechanisms mediating DID. This study included 32 female patients with DID and 43 matched healthy controls. Between-group differences in CV, thickness, and SA, the degree of spatial overlap between differences in CT and SA, and their relative contribution to differences in regional CV were assessed using a novel spatially unbiased vertex-wise approach. Whole-brain correlation analyses were performed between measures of cortical anatomy and dissociative symptoms and traumatization. Individuals with DID differed from controls in CV, CT, and SA, with significantly decreased CT in the insula, anterior cingulate, and parietal regions and reduced cortical SA in temporal and orbitofrontal cortices. Abnormalities in CT and SA shared only about 3% of all significantly different cerebral surface locations and involved distinct contributions to the abnormality of CV in DID. Significant negative associations between abnormal brain morphology (SA and CV) and dissociative symptoms and early childhood traumatization (0 and 3 years of age) were found. In DID, neuroanatomical areas with decreased CT and SA are in different locations in the brain. As CT and SA have distinct genetic and developmental origins, our findings may indicate that different neurobiological mechanisms and environmental factors impact on cortical morphology in DID, such as early childhood traumatization. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  18. Functional MRI study of cerebral cortical activation during volitional swallowing

    International Nuclear Information System (INIS)

    Wakasa, Toru; Aiga, Hideki; Yanagi, Yoshinobu; Kawai, Noriko; Sugimoto, Tomosada; Kuboki, Takuo; Kishi, Kanji

    2002-01-01

    The purpose of this study was to investigate the somatotropic distribution and lateralization of motor and sensory cortical activity during swallowing in healthy adult human subjects using functional MR imaging. Nine healthy right-handed adult volunteers (6 men, 3 women; ages 22-38) were examined. Their cortical activities were evoked by having them swallow, five times, a small bolus of water (3 ml) supplied through a plastic catheter. As a positive control, the subjects performed five repetitions of right-handed grasping tasks. Blood oxygenation level-dependent images were obtained using a 1.5 Tesla MR system (Magnetom Vision, Siemens Germany; repetition time/echo time (TR/TE)=0.96/0.66, flip angle (FA)=90 deg). T1 weighted anatomical images were obtained for the same slices in each subject. Cerebral activity was observed most notably in the primary motor cortex and primary somatosensory cortex, followed by the premotor cortex, anterior cingulate cortex, frontal operculum, and insula. The hand-grasping task activated relatively superior parts of the primary motor and somatosensory cortices. The swallowing task, on the other hand, activated the inferior parts of the pre- and postcentral gyri. The hand-grasping activation of motor and sensory cortices was localized absolutely on the contralateral side, whereas swallowing activated the motor cortex either bilaterally or unilaterally. Swallowing activated the sensory cortex almost always bilaterally. This study suggested that fMRI could be used to identify the specific areas of cortical activation caused by various tasks, and to differentiate the locations of cortical activation between tasks. (author)

  19. Functional MRI study of cerebral cortical activation during volitional swallowing

    Energy Technology Data Exchange (ETDEWEB)

    Wakasa, Toru; Aiga, Hideki; Yanagi, Yoshinobu; Kawai, Noriko; Sugimoto, Tomosada; Kuboki, Takuo; Kishi, Kanji [Okayama Univ. (Japan). Graduate School of Medicine and Dentistry

    2002-12-01

    The purpose of this study was to investigate the somatotropic distribution and lateralization of motor and sensory cortical activity during swallowing in healthy adult human subjects using functional MR imaging. Nine healthy right-handed adult volunteers (6 men, 3 women; ages 22-38) were examined. Their cortical activities were evoked by having them swallow, five times, a small bolus of water (3 ml) supplied through a plastic catheter. As a positive control, the subjects performed five repetitions of right-handed grasping tasks. Blood oxygenation level-dependent images were obtained using a 1.5 Tesla MR system (Magnetom Vision, Siemens Germany; repetition time/echo time (TR/TE)=0.96/0.66, flip angle (FA)=90 deg). T1 weighted anatomical images were obtained for the same slices in each subject. Cerebral activity was observed most notably in the primary motor cortex and primary somatosensory cortex, followed by the premotor cortex, anterior cingulate cortex, frontal operculum, and insula. The hand-grasping task activated relatively superior parts of the primary motor and somatosensory cortices. The swallowing task, on the other hand, activated the inferior parts of the pre- and postcentral gyri. The hand-grasping activation of motor and sensory cortices was localized absolutely on the contralateral side, whereas swallowing activated the motor cortex either bilaterally or unilaterally. Swallowing activated the sensory cortex almost always bilaterally. This study suggested that fMRI could be used to identify the specific areas of cortical activation caused by various tasks, and to differentiate the locations of cortical activation between tasks. (author)

  20. Visual Working Memory Is Independent of the Cortical Spacing Between Memoranda.

    Science.gov (United States)

    Harrison, William J; Bays, Paul M

    2018-03-21

    The sensory recruitment hypothesis states that visual short-term memory is maintained in the same visual cortical areas that initially encode a stimulus' features. Although it is well established that the distance between features in visual cortex determines their visibility, a limitation known as crowding, it is unknown whether short-term memory is similarly constrained by the cortical spacing of memory items. Here, we investigated whether the cortical spacing between sequentially presented memoranda affects the fidelity of memory in humans (of both sexes). In a first experiment, we varied cortical spacing by taking advantage of the log-scaling of visual cortex with eccentricity, presenting memoranda in peripheral vision sequentially along either the radial or tangential visual axis with respect to the fovea. In a second experiment, we presented memoranda sequentially either within or beyond the critical spacing of visual crowding, a distance within which visual features cannot be perceptually distinguished due to their nearby cortical representations. In both experiments and across multiple measures, we found strong evidence that the ability to maintain visual features in memory is unaffected by cortical spacing. These results indicate that the neural architecture underpinning working memory has properties inconsistent with the known behavior of sensory neurons in visual cortex. Instead, the dissociation between perceptual and memory representations supports a role of higher cortical areas such as posterior parietal or prefrontal regions or may involve an as yet unspecified mechanism in visual cortex in which stimulus features are bound to their temporal order. SIGNIFICANCE STATEMENT Although much is known about the resolution with which we can remember visual objects, the cortical representation of items held in short-term memory remains contentious. A popular hypothesis suggests that memory of visual features is maintained via the recruitment of the same neural

  1. Scene perception in posterior cortical atrophy: categorization, description and fixation patterns.

    Science.gov (United States)

    Shakespeare, Timothy J; Yong, Keir X X; Frost, Chris; Kim, Lois G; Warrington, Elizabeth K; Crutch, Sebastian J

    2013-01-01

    Partial or complete Balint's syndrome is a core feature of the clinico-radiological syndrome of posterior cortical atrophy (PCA), in which individuals experience a progressive deterioration of cortical vision. Although multi-object arrays are frequently used to detect simultanagnosia in the clinical assessment and diagnosis of PCA, to date there have been no group studies of scene perception in patients with the syndrome. The current study involved three linked experiments conducted in PCA patients and healthy controls. Experiment 1 evaluated the accuracy and latency of complex scene perception relative to individual faces and objects (color and grayscale) using a categorization paradigm. PCA patients were both less accurate (faces < scenes < objects) and slower (scenes < objects < faces) than controls on all categories, with performance strongly associated with their level of basic visual processing impairment; patients also showed a small advantage for color over grayscale stimuli. Experiment 2 involved free description of real world scenes. PCA patients generated fewer features and more misperceptions than controls, though perceptual errors were always consistent with the patient's global understanding of the scene (whether correct or not). Experiment 3 used eye tracking measures to compare patient and control eye movements over initial and subsequent fixations of scenes. Patients' fixation patterns were significantly different to those of young and age-matched controls, with comparable group differences for both initial and subsequent fixations. Overall, these findings describe the variability in everyday scene perception exhibited by individuals with PCA, and indicate the importance of exposure duration in the perception of complex scenes.

  2. Scene perception in Posterior Cortical Atrophy: categorisation, description and fixation patterns

    Directory of Open Access Journals (Sweden)

    Timothy J Shakespeare

    2013-10-01

    Full Text Available Partial or complete Balint’s syndrome is a core feature of the clinico-radiological syndrome of posterior cortical atrophy (PCA, in which individuals experience a progressive deterioration of cortical vision. Although multi-object arrays are frequently used to detect simultanagnosia in the clinical assessment and diagnosis of PCA, to date there have been no group studies of scene perception in patients with the syndrome. The current study involved three linked experiments conducted in PCA patients and healthy controls. Experiment 1 evaluated the accuracy and latency of complex scene perception relative to individual faces and objects (colour and greyscale using a categorisation paradigm. PCA patients were both less accurate (faces

  3. Distinct slow and fast cortical theta dynamics in episodic memory retrieval.

    Science.gov (United States)

    Pastötter, Bernhard; Bäuml, Karl-Heinz T

    2014-07-01

    Brain oscillations in the theta frequency band (3-8 Hz) have been shown to be critically involved in human episodic memory retrieval. In prior work, both positive and negative relationships between cortical theta power and retrieval success have been reported. This study examined the hypothesis that slow and fast cortical theta oscillations at the edges of the traditional theta frequency band are differentially related to retrieval success. Scalp EEG was recorded in healthy human participants as they performed a cued-recall episodic memory task. Slow (~3 Hz) and fast (~7 Hz) theta oscillations at retrieval were examined as a function of whether an item was recalled or not and as a function of the items' output position at test. Recall success typically declines with output position, due to increases in interference level. The results showed that slow theta power was positively related but fast theta power was negatively related to retrieval success. Concurrent positive and negative episodic memory effects for slow and fast theta oscillations were dissociable in time and space, showing different time courses and different spatial locations on the scalp. Moreover, fast theta power increased from early to late output positions, whereas slow theta power was unaffected by items' output position. Together with prior work, the results suggest that slow and fast theta oscillations have distinct functional roles in episodic memory retrieval, with slow theta oscillations being related to processes of recollection and conscious awareness, and fast theta oscillations being linked to processes of interference and interference resolution. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. Polarization-sensitive color in butterfly scales: polarization conversion from ridges with reflecting elements.

    Science.gov (United States)

    Zhang, Ke; Tang, Yiwen; Meng, Jinsong; Wang, Ge; Zhou, Han; Fan, Tongxiang; Zhang, Di

    2014-11-03

    Polarization-sensitive color originates from polarization-dependent reflection or transmission, exhibiting abundant light information, including intensity, spectral distribution, and polarization. A wide range of butterflies are physiologically sensitive to polarized light, but the origins of polarized signal have not been fully understood. Here we systematically investigate the colorful scales of six species of butterfly to reveal the physical origins of polarization-sensitive color. Microscopic optical images under crossed polarizers exhibit their polarization-sensitive characteristic, and micro-structural characterizations clarify their structural commonality. In the case of the structural scales that have deep ridges, the polarization-sensitive color related with scale azimuth is remarkable. Periodic ridges lead to the anisotropic effective refractive indices in the parallel and perpendicular grating orientations, which achieves form-birefringence, resulting in the phase difference of two different component polarized lights. Simulated results show that ridge structures with reflecting elements reflect and rotate the incident p-polarized light into s-polarized light. The dimensional parameters and shapes of grating greatly affect the polarization conversion process, and the triangular deep grating extends the outstanding polarization conversion effect from the sub-wavelength period to the period comparable to visible light wavelength. The parameters of ridge structures in butterfly scales have been optimized to fulfill the polarization-dependent reflection for secret communication. The structural and physical origin of polarization conversion provides a more comprehensive perspective on the creation of polarization-sensitive color in butterfly wing scales. These findings show great potential in anti-counterfeiting technology and advanced optical material design.

  5. APECS: A Network for Polar Early Career Scientist Professional Development

    Science.gov (United States)

    Enderlin, E. M.

    2014-12-01

    The Association of Polar Early Career Researchers (APECS) is an international and interdisciplinary organization for undergraduate and graduate students, postdoctoral researchers, early faculty members, educators and others with interests in the polar regions, alpine regions and the wider Cryosphere. APECS is a scientific, non-profit organization with free individual membership that aims to stimulate research collaborations and develop effective future leaders in polar research, education, and outreach. APECS grew out of the 4th International Polar Year (2007-08), which emphasized the need to stimulate and nurture the next generation of scientists in order to improve the understanding and communication of the polar regions and its global connections. The APECS organizational structure includes a Council and an elected Executive Committee that are supported by a Directorate. These positions are open to all individual members through a democratic process. The APECS Directorate is funded by the Norwegian Research Council, the University of Tromsø and the Norwegian Polar Institute and is hosted by the University of Tromsø. Early career scientists benefit from a range of activities hosted/organized by APECS. Every year, numerous activities are run with partner organizations and in conjunction with major polar conferences and meetings. In-person and online panels and workshops focus on a range of topics, from developing field skills to applying for a job after graduate school. Career development webinars are hosted each fall and topical research webinars are hosted throughout the year and archived online (http://www.apecs.is). The APECS website also contains abundant information on polar news, upcoming conferences and meetings, and job postings for early career scientists. To better respond to members' needs, APECS has national/regional committees that are linked to the international overarching organization. Many of these committees organize regional meetings or

  6. Is the Alzheimer's disease cortical thickness signature a biological marker for memory?

    Science.gov (United States)

    Busovaca, Edgar; Zimmerman, Molly E; Meier, Irene B; Griffith, Erica Y; Grieve, Stuart M; Korgaonkar, Mayuresh S; Williams, Leanne M; Brickman, Adam M

    2016-06-01

    Recent work suggests that analysis of the cortical thickness in key brain regions can be used to identify individuals at greatest risk for development of Alzheimer's disease (AD). It is unclear to what extent this "signature" is a biological marker of normal memory function - the primary cognitive domain affected by AD. We examined the relationship between the AD signature biomarker and memory functioning in a group of neurologically healthy young and older adults. Cortical thickness measurements and neuropsychological evaluations were obtained in 110 adults (age range 21-78, mean = 46) drawn from the Brain Resource International Database. The cohort was divided into young adult (n = 64, age 21-50) and older adult (n = 46, age 51-78) groups. Cortical thickness analysis was performed with FreeSurfer, and the average cortical thickness extracted from the eight regions that comprise the AD signature. Mean AD-signature cortical thickness was positively associated with performance on the delayed free recall trial of a list learning task and this relationship did not differ between younger and older adults. Mean AD-signature cortical thickness was not associated with performance on a test of psychomotor speed, as a control task, in either group. The results suggest that the AD signature cortical thickness is a marker for memory functioning across the adult lifespan.

  7. Inhibition of polar calcium movement and gravitropism in roots treated with auxin-transport inhibitors

    Science.gov (United States)

    Lee, J. S.; Mulkey, T. J.; Evans, M. L.

    1984-01-01

    Primary roots of maize (Zea mays L.) and pea (Pisum sativum L.) exhibit strong positive gravitropism. In both species, gravistimulation induces polar movement of calcium across the root tip from the upper side to the lower side. Roots of onion (Allium cepa L.) are not responsive to gravity and gravistimulation induces little or no polar movement of calcium across the root tip. Treatment of maize or pea roots with inhibitors of auxin transport (morphactin, naphthylphthalamic acid, 2,3,5-triiodobenzoic acid) prevents both gravitropism and gravity-induced polar movement of calcium across the root tip. The results indicate that calcium movement and auxin movement are closely linked in roots and that gravity-induced redistribution of calcium across the root cap may play an important role in the development of gravitropic curvature.

  8. Bilateral Cerebellar Cortical Dysplasia without Other Malformations: A Case Report

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Jung Seok; Ahn Kook Jin; Kim, Jee Young; Lee, Sun Jin; Park, Jeong Mi [Catholic University Yeouido St. Mary' s Hospital, College of Medicine, Seoul (Korea, Republic of)

    2010-06-15

    Recent advances in MRI have revealed congenital brain malformations and subtle developmental abnormalities of the cerebral and cerebellar cortical architecture. Typical cerebellar cortical dysplasia as a newly categorized cerebellar malformation, has been seen in patients with Fukuyama congenital muscular dystrophy. Cerebellar cortical dysplasia occurs at the embryonic stage and is often observed in healthy newborns. It is also incidentally and initially detected in adults without symptoms. To the best of our knowledge, cerebellar dysplasia without any related disorders is very rare. We describe the MRI findings in one patient with disorganized foliation of both cerebellar hemispheres without a related disorder or syndrome

  9. Acute hepatic encephalopathy presenting as cortical laminar necrosis: Case report

    International Nuclear Information System (INIS)

    Choi, Jong Mun; Kim, Yoon Hee; Roh, Sook Young

    2013-01-01

    We report on a 55-year-old man with alcoholic liver cirrhosis who presented with status epilepticus. Laboratory analysis showed markedly elevated blood ammonia. Brain magnetic resonance imaging (MRI) showed widespread cortical signal changes with restricted diffusion, involving both temporo-fronto-parietal cortex, while the perirolandic regions and occipital cortex were uniquely spared. A follow-up brain MRI demonstrated diffuse cortical atrophy with increased signals on T1-weighted images in both the basal ganglia and temporal lobe cortex, representing cortical laminar necrosis. We suggest that the brain lesions, in our case, represent a consequence of toxic effect of ammonia.

  10. Acute hepatic encephalopathy presenting as cortical laminar necrosis: Case report

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jong Mun; Kim, Yoon Hee; Roh, Sook Young [Bundang Jesaeng General Hospital, Daejin Medical Center, Seongnam (Korea, Republic of)

    2013-04-15

    We report on a 55-year-old man with alcoholic liver cirrhosis who presented with status epilepticus. Laboratory analysis showed markedly elevated blood ammonia. Brain magnetic resonance imaging (MRI) showed widespread cortical signal changes with restricted diffusion, involving both temporo-fronto-parietal cortex, while the perirolandic regions and occipital cortex were uniquely spared. A follow-up brain MRI demonstrated diffuse cortical atrophy with increased signals on T1-weighted images in both the basal ganglia and temporal lobe cortex, representing cortical laminar necrosis. We suggest that the brain lesions, in our case, represent a consequence of toxic effect of ammonia.

  11. System for measuring the proton polarization in a polarized target

    International Nuclear Information System (INIS)

    Karnaukhov, I.M.; Lukhanin, A.A.; Telegin, Yu.N.; Trotsenko, V.I.; Chechetenko, V.F.

    1984-01-01

    The system for measuring the proton polarization in a polarized target representing the high-sensitivity nuclear magnetic resonance (NMR) is described Q-meter with series connection and a circuit for measuring system resonance characteristic is used for NMR-absorption signal recording. Measuring coil is produced of a strip conductor in order to obtain uniform system sensitivity to polarization state in all target volume and improve signal-to-noise ratio. Polarization measuring system operates ion-line with the M-6000 computer. The total measuring error for the value of free proton polarization in target taking into account the error caused by local depolarization of working substance under irradiation by high-intense photon beam is <= 6%. Long-term application of the described system for measuring the proton polarization in the LUEh-20000 accelerator target used in the pion photoproduction experiments has demonstrated its high reliability

  12. Sources of polarized neutrons

    International Nuclear Information System (INIS)

    Walter, L.

    1983-01-01

    Various sources of polarized neutrons are reviewed. Monoenergetic source produced with unpolarized or polarized beams, white sources of polarized neutrons, production by transmissions through polarized hydrogen targets and polarized thermal neutronsare discussed, with appropriate applications included. (U.K.)

  13. Cortical Thickness and Episodic Memory Impairment in Systemic Lupus Erythematosus.

    Science.gov (United States)

    Bizzo, Bernardo Canedo; Sanchez, Tiago Arruda; Tukamoto, Gustavo; Zimmermann, Nicolle; Netto, Tania Maria; Gasparetto, Emerson Leandro

    2017-01-01

    The purpose of this study was to investigate differences in brain cortical thickness of systemic lupus erythematosus (SLE) patients with and without episodic memory impairment and healthy controls. We studied 51 patients divided in 2 groups (SLE with episodic memory deficit, n = 17; SLE without episodic memory deficit, n = 34) by the Rey Auditory Verbal Learning Test and 34 healthy controls. Groups were paired based on sex, age, education, Mini-Mental State Examination score, and accumulation of disease burden. Cortical thickness from magnetic resonance imaging scans was determined using the FreeSurfer software package. SLE patients with episodic memory deficits presented reduced cortical thickness in the left supramarginal cortex and superior temporal gyrus when compared to the control group and in the right superior frontal, caudal, and rostral middle frontal and precentral gyri when compared to the SLE group without episodic memory impairment considering time since diagnosis of SLE as covaried. There were no significant differences in the cortical thickness between the SLE without episodic memory and control groups. Different memory-related cortical regions thinning were found in the episodic memory deficit group when individually compared to the groups of patients without memory impairment and healthy controls. Copyright © 2016 by the American Society of Neuroimaging.

  14. Changes in cortical cytoskeletal and extracellular matrix gene expression in prostate cancer are related to oncogenic ERG deregulation

    International Nuclear Information System (INIS)

    Schulz, Wolfgang A; Ingenwerth, Marc; Djuidje, Carolle E; Hader, Christiane; Rahnenführer, Jörg; Engers, Rainer

    2010-01-01

    The cortical cytoskeleton network connects the actin cytoskeleton to various membrane proteins, influencing cell adhesion, polarity, migration and response to extracellular signals. Previous studies have suggested changes in the expression of specific components in prostate cancer, especially of 4.1 proteins (encoded by EPB41 genes) which form nodes in this network. Expression of EPB41L1, EPB41L2, EPB41L3 (protein: 4.1B), EPB41L4B (EHM2), EPB41L5, EPB49 (dematin), VIL2 (ezrin), and DLG1 (summarized as „cortical cytoskeleton' genes) as well as ERG was measured by quantitative RT-PCR in a well-characterized set of 45 M0 prostate adenocarcinoma and 13 benign tissues. Hypermethylation of EPB41L3 and GSTP1 was compared in 93 cancer tissues by methylation-specific PCR. Expression of 4.1B was further studied by immunohistochemistry. EPB41L1 and EPB41L3 were significantly downregulated and EPB41L4B was upregulated in cancer tissues. Low EPB41L1 or high EPB41L4B expression were associated with earlier biochemical recurrence. None of the other cortical cytoskeleton genes displayed expression changes, in particular EPB49 and VIL2, despite hints from previous studies. EPB41L3 downregulation was significantly associated with hypermethylation of its promoter and strongly correlated with GSTP1 hypermethylation. Protein 4.1B was detected most strongly in the basal cells of normal prostate epithelia. Its expression in carcinoma cells was similar to the weaker one in normal luminal cells. EPB41L3 downregulation and EPB41L4B upregulation were essentially restricted to the 22 cases with ERG overexpression. Expression changes in EPB41L3 and EPB41L4B closely paralleled those previously observed for the extracellular matrix genes FBLN1 and SPOCK1, respectively. Specific changes in the cortical cytoskeleton were observed during prostate cancer progression. They parallel changes in the expression of extracellular matrix components and all together appear to be associated with

  15. Mediterranean diet, micronutrients and macronutrients, and MRI measures of cortical thickness.

    Science.gov (United States)

    Staubo, Sara C; Aakre, Jeremiah A; Vemuri, Prashanthi; Syrjanen, Jeremy A; Mielke, Michelle M; Geda, Yonas E; Kremers, Walter K; Machulda, Mary M; Knopman, David S; Petersen, Ronald C; Jack, Clifford R; Roberts, Rosebud O

    2017-02-01

    The Mediterranean diet (MeDi) is associated with reduced risk of cognitive impairment, but it is unclear whether it is associated with better brain imaging biomarkers. Among 672 cognitively normal participants (mean age, 79.8 years, 52.5% men), we investigated associations of MeDi score and MeDi components with magnetic resonance imaging measures of cortical thickness for the four lobes separately and averaged (average lobar). Higher MeDi score was associated with larger frontal, parietal, occipital, and average lobar cortical thickness. Higher legume and fish intakes were associated with larger cortical thickness: legumes with larger superior parietal, inferior parietal, precuneus, parietal, occipital, lingual, and fish with larger precuneus, superior parietal, posterior cingulate, parietal, and inferior parietal. Higher carbohydrate and sugar intakes were associated with lower entorhinal cortical thickness. In this sample of elderly persons, higher adherence to MeDi was associated with larger cortical thickness. These cross-sectional findings require validation in prospective studies. Copyright © 2016 the Alzheimer's Association. Published by Elsevier Inc. All rights reserved.

  16. PolarHub: A Global Hub for Polar Data Discovery

    Science.gov (United States)

    Li, W.

    2014-12-01

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

  17. Cortical laminar necrosis in brain infarcts: serial MRI

    Energy Technology Data Exchange (ETDEWEB)

    Siskas, N.; Lefkopoulos, A.; Ioannidis, I.; Charitandi, A.; Dimitriadis, A.S. [Radiology Department, AHEPA University Hospital, Aristotele University of Thessaloniki (Greece)

    2003-05-01

    High-signal cortical lesions are observed on T1-weighted images in cases of brain infarct. Histological examination has demonstrated these to be ''cortical laminar necrosis'', without haemorrhage or calcification. We report serial MRI in this condition in 12 patients with brain infarcts. We looked at high-signal lesions on T1-weighted images, chronological changes in signal intensity and contrast enhancement. High-signal cortical lesions began to appear about 2 weeks after the ictus, were prominent at 1 - 2 months, then became less evident, but occasionally remained for up to 1.5 years. They gave high signal or were isointense on T2-weighted images and did not give low signal at any stage. Contrast enhancement of these lesions was prominent at 1 - 2 months, and less apparent from 3 months, but was seen up to 5 months. (orig.)

  18. Polarization extinction ratio of the polarization crosstalk caused by point pressure force in the polarization-maintaining fiber

    Science.gov (United States)

    Mukhtubayev, Azamat B.; Aksarin, Stanislav M.; Strigalev, Vladimir E.

    2017-11-01

    A study of the orthogonal polarization modes crosstalk changes in the point of different mechanical actions (pressure force) in the polarization-maintaining fiber with straining elliptical cladding is presented. It was found that by increasing of the pressure force the polarization extinction ratio increases nonlinearly. Also revealed the dependence of the extinction coefficient and the angle between vector of the mechanical action and polarization axes of the test fiber, which leads to change the extinction coefficient variable from -57 dB to -25 dB under the pressure force of 0.7 N. Also it was found that the cross angle of the fiber axes doesn't influence on the extinction ratio value of the mechanical induced polarization crosstalk.

  19. Cortical hypermetabolism in MCI subjects: a compensatory mechanism?

    International Nuclear Information System (INIS)

    Ashraf, A.; Fan, Z.; Brooks, D.J.; Edison, P.

    2015-01-01

    Alzheimer's disease (AD) is associated with amyloid accumulation that takes place decades before symptoms appear. Cognitive impairment in AD is associated with reduced glucose metabolism. However, neuronal plasticity/compensatory mechanisms might come into play before the onset of dementia. The aim of this study was to determine whether there is evidence of cortical hypermetabolism as a compensatory mechanism before amyloid deposition takes place in subjects with amnestic mild cognitive impairment (aMCI). Nine AD subjects and ten aMCI subjects had both [ 11 C]PIB and [ 18 F]FDG PET scans with arterial input in order to quantify the amyloid deposition and glucose metabolism in vivo in comparison with healthy control subjects who underwent either [ 11 C]PIB or [ 18 F]FDG PET scans. The [ 11 C]PIB PET scans were quantified using [ 11 C]PIB target region to cerebellum uptake ratio images created by integrating the activity collected from 60 to 90 min, and regional cerebral glucose metabolism was quantified using spectral analysis. In MCI subjects, cortical hypermetabolism was observed in four amyloid-negative subjects and one amyloid-positive subject, while hypometabolism was seen in five other MCI subjects with high amyloid load. Subjects with hypermetabolism and low amyloid did not convert to AD during clinical follow-up for 18 months in contrast to four amyloid-positive hypometabolic subjects who did convert to AD. This preliminary study suggests that compensatory hypermetabolism can occur in aMCI subjects, particularly in those who are amyloid-negative. The increase in metabolic rate in different cortical regions with predominance in the occipital cortex may be a compensatory response to the neuronal damage occurring early in the disease process. It may also reflect recruitment of relatively minimally affected cortical regions to compensate for reduced function in the temporoparietal cortical association areas. (orig.)

  20. Cortical hypermetabolism in MCI subjects: a compensatory mechanism?

    Energy Technology Data Exchange (ETDEWEB)

    Ashraf, A.; Fan, Z.; Brooks, D.J.; Edison, P. [Imperial College London, Neurology Imaging Unit, Division of Brain Sciences, London (United Kingdom)

    2014-09-30

    Alzheimer's disease (AD) is associated with amyloid accumulation that takes place decades before symptoms appear. Cognitive impairment in AD is associated with reduced glucose metabolism. However, neuronal plasticity/compensatory mechanisms might come into play before the onset of dementia. The aim of this study was to determine whether there is evidence of cortical hypermetabolism as a compensatory mechanism before amyloid deposition takes place in subjects with amnestic mild cognitive impairment (aMCI). Nine AD subjects and ten aMCI subjects had both [{sup 11}C]PIB and [{sup 18}F]FDG PET scans with arterial input in order to quantify the amyloid deposition and glucose metabolism in vivo in comparison with healthy control subjects who underwent either [{sup 11}C]PIB or [{sup 18}F]FDG PET scans. The [{sup 11}C]PIB PET scans were quantified using [{sup 11}C]PIB target region to cerebellum uptake ratio images created by integrating the activity collected from 60 to 90 min, and regional cerebral glucose metabolism was quantified using spectral analysis. In MCI subjects, cortical hypermetabolism was observed in four amyloid-negative subjects and one amyloid-positive subject, while hypometabolism was seen in five other MCI subjects with high amyloid load. Subjects with hypermetabolism and low amyloid did not convert to AD during clinical follow-up for 18 months in contrast to four amyloid-positive hypometabolic subjects who did convert to AD. This preliminary study suggests that compensatory hypermetabolism can occur in aMCI subjects, particularly in those who are amyloid-negative. The increase in metabolic rate in different cortical regions with predominance in the occipital cortex may be a compensatory response to the neuronal damage occurring early in the disease process. It may also reflect recruitment of relatively minimally affected cortical regions to compensate for reduced function in the temporoparietal cortical association areas. (orig.)

  1. Low-frequency hippocampal-cortical activity drives brain-wide resting-state functional MRI connectivity.

    Science.gov (United States)

    Chan, Russell W; Leong, Alex T L; Ho, Leon C; Gao, Patrick P; Wong, Eddie C; Dong, Celia M; Wang, Xunda; He, Jufang; Chan, Ying-Shing; Lim, Lee Wei; Wu, Ed X

    2017-08-15

    The hippocampus, including the dorsal dentate gyrus (dDG), and cortex engage in bidirectional communication. We propose that low-frequency activity in hippocampal-cortical pathways contributes to brain-wide resting-state connectivity to integrate sensory information. Using optogenetic stimulation and brain-wide fMRI and resting-state fMRI (rsfMRI), we determined the large-scale effects of spatiotemporal-specific downstream propagation of hippocampal activity. Low-frequency (1 Hz), but not high-frequency (40 Hz), stimulation of dDG excitatory neurons evoked robust cortical and subcortical brain-wide fMRI responses. More importantly, it enhanced interhemispheric rsfMRI connectivity in various cortices and hippocampus. Subsequent local field potential recordings revealed an increase in slow oscillations in dorsal hippocampus and visual cortex, interhemispheric visual cortical connectivity, and hippocampal-cortical connectivity. Meanwhile, pharmacological inactivation of dDG neurons decreased interhemispheric rsfMRI connectivity. Functionally, visually evoked fMRI responses in visual regions also increased during and after low-frequency dDG stimulation. Together, our results indicate that low-frequency activity robustly propagates in the dorsal hippocampal-cortical pathway, drives interhemispheric cortical rsfMRI connectivity, and mediates visual processing.

  2. Polarized secondary radioactive beams

    International Nuclear Information System (INIS)

    Zaika, N.I.

    1992-01-01

    Three methods of polarized radioactive nuclei beam production: a) a method nuclear interaction of the non-polarized or polarized charged projectiles with target nuclei; b) a method of polarization of stopped reaction radioactive products in a special polarized ion source with than following acceleration; c) a polarization of radioactive nuclei circulating in a storage ring are considered. Possible life times of the radioactive ions for these methods are determined. General schemes of the polarization method realizations and depolarization problems are discussed

  3. Rasmussen's encephalitis presenting as focal cortical dysplasia

    Directory of Open Access Journals (Sweden)

    D.J. O'Rourke

    2014-01-01

    Full Text Available Rasmussen's encephalitis is a rare syndrome characterized by intractable seizures, often associated with epilepsia partialis continua and symptoms of progressive hemispheric dysfunction. Seizures are usually the hallmark of presentation, but antiepileptic drug treatment fails in most patients and is ineffective against epilepsia partialis continua, which often requires surgical intervention. Co-occurrence of focal cortical dysplasia has only rarely been described and may have implications regarding pathophysiology and management. We describe a rare case of dual pathology of Rasmussen's encephalitis presenting as a focal cortical dysplasia (FCD and discuss the literature on this topic.

  4. Small vessel disease is linked to disrupted structural network covariance in Alzheimer's disease.

    Science.gov (United States)

    Nestor, Sean M; Mišić, Bratislav; Ramirez, Joel; Zhao, Jiali; Graham, Simon J; Verhoeff, Nicolaas P L G; Stuss, Donald T; Masellis, Mario; Black, Sandra E

    2017-07-01

    Cerebral small vessel disease (SVD) is thought to contribute to Alzheimer's disease (AD) through abnormalities in white matter networks. Gray matter (GM) hub covariance networks share only partial overlap with white matter connectivity, and their relationship with SVD has not been examined in AD. We developed a multivariate analytical pipeline to elucidate the cortical GM thickness systems that covary with major network hubs and assessed whether SVD and neurodegenerative pathologic markers were associated with attenuated covariance network integrity in mild AD and normal elderly control subjects. SVD burden was associated with reduced posterior cingulate corticocortical GM network integrity and subneocorticocortical hub network integrity in AD. These findings provide evidence that SVD is linked to the selective disruption of cortical hub GM networks in AD brains and point to the need to consider GM hub covariance networks when assessing network disruption in mixed disease. Copyright © 2017 the Alzheimer's Association. Published by Elsevier Inc. All rights reserved.

  5. Scattering of polarized electrons from polarized targets: Coincidence reactions and prescriptions for polarized half-off-shell single-nucleon cross sections

    International Nuclear Information System (INIS)

    Caballero, J.A.; Massachusetts Inst. of Tech., Cambridge, MA; Donnelly, T.W.; Massachusetts Inst. of Tech., Cambridge, MA; Poulis, G.I.; Massachusetts Inst. of Tech., Cambridge, MA

    1993-01-01

    Coincidence reactions of the type vector A( vector e, e'N)B involving the scattering of polarized electrons from polarized targets are discussed within the context of the plane-wave impulse approximation. Prescriptions are developed for polarized half-off single-nucleon cross sections; the different prescriptions are compared for typical quasi-free kinematics. Illustrative results are presented for coincidence polarized electron scattering from typical polarized nuclei. (orig.)

  6. Curved planar reconstruction of MR images in focal cortical dysplasia of the brain

    International Nuclear Information System (INIS)

    Chung, Gyung Ho; Lee, Sang Yong; Kim, Chong So; Kim, Young Kon; Lee, Young Hwan; Jeong, Su Hyun

    2002-01-01

    To describe curved planar reconstruction imaging (CPR) and determine its usefulness in the evaluation of focal cortical dysplasia of the brain. In 17 cases of focal cortical dysplasia (cortical dysplasia (n=9), schizencephaly (n=5), and heterotopia (n=3), CPR images were created using a multiplanar reconstruction program and imaging data obtained during T1 magnetization prepared rapid acquisition gradient-echo MR imaging. We assessed the precise configuration of abnormalities and their relation to adjacent gyri and sulci. CPRI showed the brain cortex as a 2D panoramic image, demonstrating the precise configurations and locations of dysplasia-associated abnormalities and their relation to adjacent gyri and sulci, and the precise shape of the gray-white matter interface. CPRI can provide important radiological information about the extension and configuration of focal cortical dysplasia, and its relation to neighboring cortical structures. We believe that CPRI should form an essential part of the routine investigation os suspected cases of focal cortical dysplasia

  7. Effect of porosity, tissue density, and mechanical properties on radial sound speed in human cortical bone

    Energy Technology Data Exchange (ETDEWEB)

    Eneh, C. T. M., E-mail: chibuzor.eneh@uef.fi, E-mail: markus.malo@uef.fi, E-mail: janne.karjalainen@boneindex.fi, E-mail: jukka.liukkonen@gmail.com, E-mail: juha.toyras@uef.fi; Töyräs, J., E-mail: chibuzor.eneh@uef.fi, E-mail: markus.malo@uef.fi, E-mail: janne.karjalainen@boneindex.fi, E-mail: jukka.liukkonen@gmail.com, E-mail: juha.toyras@uef.fi; Jurvelin, J. S., E-mail: jukka.jurvelin@uef.fi [Department of Applied Physics, University of Eastern Finland, P.O. Box 1627, Kuopio FI-70211, Finland and Diagnostic Imaging Center, Kuopio University Hospital, P.O. Box 100, Kuopio FI-70029 (Finland); Malo, M. K. H., E-mail: chibuzor.eneh@uef.fi, E-mail: markus.malo@uef.fi, E-mail: janne.karjalainen@boneindex.fi, E-mail: jukka.liukkonen@gmail.com, E-mail: juha.toyras@uef.fi; Liukkonen, J., E-mail: chibuzor.eneh@uef.fi, E-mail: markus.malo@uef.fi, E-mail: janne.karjalainen@boneindex.fi, E-mail: jukka.liukkonen@gmail.com, E-mail: juha.toyras@uef.fi [Department of Applied Physics, University of Eastern Finland, P.O. Box 1627, Kuopio FI-70211 (Finland); Karjalainen, J. P., E-mail: chibuzor.eneh@uef.fi, E-mail: markus.malo@uef.fi, E-mail: janne.karjalainen@boneindex.fi, E-mail: jukka.liukkonen@gmail.com, E-mail: juha.toyras@uef.fi [Bone Index Finland Ltd., P.O. Box 1188, Kuopio FI-70211 (Finland)

    2016-05-15

    Purpose: The purpose of this study was to investigate the effect of simultaneous changes in cortical porosity, tissue mineral density, and elastic properties on radial speed of sound (SOS) in cortical bone. The authors applied quantitative pulse-echo (PE) ultrasound techniques that hold much potential especially for screening of osteoporosis at primary healthcare facilities. Currently, most PE measurements of cortical thickness, a well-known indicator of fracture risk, use a predefined estimate for SOS in bone to calculate thickness. Due to variation of cortical bone porosity, the use of a constant SOS value propagates to an unknown error in cortical thickness assessment by PE ultrasound. Methods: The authors conducted 2.25 and 5.00 MHz focused PE ultrasound time of flight measurements on femoral diaphyses of 18 cadavers in vitro. Cortical porosities of the samples were determined using microcomputed tomography and related to SOS in the samples. Additionally, the effect of cortical bone porosity and mechanical properties of the calcified matrix on SOS was investigated using numerical finite difference time domain simulations. Results: Both experimental measurements and simulations demonstrated significant negative correlation between radial SOS and cortical porosity (R{sup 2} ≥ 0.493, p < 0.01 and R{sup 2} ≥ 0.989, p < 0.01, respectively). When a constant SOS was assumed for cortical bone, the error due to variation of cortical bone porosity (4.9%–16.4%) was about 6% in the cortical thickness assessment in vitro. Conclusions: Use of a predefined, constant value for radial SOS in cortical bone, i.e., neglecting the effect of measured variation in cortical porosity, propagated to an error of 6% in cortical thickness. This error can be critical as characteristic cortical thinning of 1.10% ± 1.06% per yr decreases bending strength of the distal radius and results in increased fragility in postmenopausal women. Provided that the cortical porosity can be estimated

  8. Effect of porosity, tissue density, and mechanical properties on radial sound speed in human cortical bone

    International Nuclear Information System (INIS)

    Eneh, C. T. M.; Töyräs, J.; Jurvelin, J. S.; Malo, M. K. H.; Liukkonen, J.; Karjalainen, J. P.

    2016-01-01

    Purpose: The purpose of this study was to investigate the effect of simultaneous changes in cortical porosity, tissue mineral density, and elastic properties on radial speed of sound (SOS) in cortical bone. The authors applied quantitative pulse-echo (PE) ultrasound techniques that hold much potential especially for screening of osteoporosis at primary healthcare facilities. Currently, most PE measurements of cortical thickness, a well-known indicator of fracture risk, use a predefined estimate for SOS in bone to calculate thickness. Due to variation of cortical bone porosity, the use of a constant SOS value propagates to an unknown error in cortical thickness assessment by PE ultrasound. Methods: The authors conducted 2.25 and 5.00 MHz focused PE ultrasound time of flight measurements on femoral diaphyses of 18 cadavers in vitro. Cortical porosities of the samples were determined using microcomputed tomography and related to SOS in the samples. Additionally, the effect of cortical bone porosity and mechanical properties of the calcified matrix on SOS was investigated using numerical finite difference time domain simulations. Results: Both experimental measurements and simulations demonstrated significant negative correlation between radial SOS and cortical porosity (R"2 ≥ 0.493, p < 0.01 and R"2 ≥ 0.989, p < 0.01, respectively). When a constant SOS was assumed for cortical bone, the error due to variation of cortical bone porosity (4.9%–16.4%) was about 6% in the cortical thickness assessment in vitro. Conclusions: Use of a predefined, constant value for radial SOS in cortical bone, i.e., neglecting the effect of measured variation in cortical porosity, propagated to an error of 6% in cortical thickness. This error can be critical as characteristic cortical thinning of 1.10% ± 1.06% per yr decreases bending strength of the distal radius and results in increased fragility in postmenopausal women. Provided that the cortical porosity can be estimated in vivo

  9. Ortho-Babinet polarization-interrogating filter: an interferometric approach to polarization measurement.

    Science.gov (United States)

    Van Delden, Jay S

    2003-07-15

    A novel, interferometric, polarization-interrogating filter assembly and method for the simultaneous measurement of all four Stokes parameters across a partially polarized irradiance image in a no-moving-parts, instantaneous, highly sensitive manner is described. In the reported embodiment of the filter, two spatially varying linear retarders and a linear polarizer comprise an ortho-Babinet, polarization-interrogating (OBPI) filter. The OBPI filter uniquely encodes the incident ensemble of electromagnetic wave fronts comprising a partially polarized irradiance image in a controlled, deterministic, spatially varying manner to map the complete state of polarization across the image to local variations in a superposed interference pattern. Experimental interferograms are reported along with a numerical simulation of the method.

  10. Ultrasound evaluation of cortical brain development in fetuses with intrauterine growth restriction.

    Science.gov (United States)

    Businelli, Caterina; de Wit, Charlotte; Visser, Gerard H A; Pistorius, Lourens R

    2014-09-10

    Abstract Objective: We evaluated the ultrasound appearance of brain volume and cortical development in fetuses with early growth restriction and placental insufficiency. Methods: We examined a cohort of 20 fetuses with severe intrauterine growth restriction (IUGR) and evidence of placental insufficiency by three-dimensional (3D) ultrasound between 24 and 34 weeks. We graded cortical development and measured the supratentorial intracranial volume. The cortical grading and volume were compared to data obtained from a reference population of 28 adequate for gestational age (AGA) fetuses. Results: Ultrasound examinations were performed in 20 fetuses with IUGR. The biometry and brain volume were significantly reduced in IUGR fetuses. There was evidence of accelerated cortical development in IUGR fetuses. Conclusion: This study confirms that the smaller brain volume in IUGR fetuses, with normal or accelerated cortical maturation as previously depicted with postnatal MRI examination, can be demonstrated by prenatal 3D ultrasound.

  11. Relating normalization to neuronal populations across cortical areas.

    Science.gov (United States)

    Ruff, Douglas A; Alberts, Joshua J; Cohen, Marlene R

    2016-09-01

    Normalization, which divisively scales neuronal responses to multiple stimuli, is thought to underlie many sensory, motor, and cognitive processes. In every study where it has been investigated, neurons measured in the same brain area under identical conditions exhibit a range of normalization, ranging from suppression by nonpreferred stimuli (strong normalization) to additive responses to combinations of stimuli (no normalization). Normalization has been hypothesized to arise from interactions between neuronal populations, either in the same or different brain areas, but current models of normalization are not mechanistic and focus on trial-averaged responses. To gain insight into the mechanisms underlying normalization, we examined interactions between neurons that exhibit different degrees of normalization. We recorded from multiple neurons in three cortical areas while rhesus monkeys viewed superimposed drifting gratings. We found that neurons showing strong normalization shared less trial-to-trial variability with other neurons in the same cortical area and more variability with neurons in other cortical areas than did units with weak normalization. Furthermore, the cortical organization of normalization was not random: neurons recorded on nearby electrodes tended to exhibit similar amounts of normalization. Together, our results suggest that normalization reflects a neuron's role in its local network and that modulatory factors like normalization share the topographic organization typical of sensory tuning properties. Copyright © 2016 the American Physiological Society.

  12. Coronal Polarization of Pseudostreamers and the Solar Polar Field Reversal

    Science.gov (United States)

    Rachmeler, L. A.; Guennou, C.; Seaton, D. B.; Gibson, S. E.; Auchere, F.

    2016-01-01

    The reversal of the solar polar magnetic field is notoriously hard to pin down due to the extreme viewing angle of the pole. In Cycle 24, the southern polar field reversal can be pinpointed with high accuracy due to a large-scale pseudostreamer that formed over the pole and persisted for approximately a year. We tracked the size and shape of this structure with multiple observations and analysis techniques including PROBA2/SWAP EUV images, AIA EUV images, CoMP polarization data, and 3D tomographic reconstructions. We find that the heliospheric field reversed polarity in February 2014, whereas in the photosphere, the last vestiges of the previous polar field polarity remained until March 2015. We present here the evolution of the structure and describe its identification in the Fe XII 1074nm coronal emission line, sensitive to the Hanle effect in the corona.

  13. Experiments with Fermilab polarized proton and polarized antiproton beams

    International Nuclear Information System (INIS)

    Yokosawa, A.

    1990-01-01

    We summarize activities concerning the Fermilab polarized beams. They include a brief description of the polarized-beam facility, measurements of beam polarization by polarimeters, asymmetry measurements in the π degree production at high p perpendicular and in the Λ (Σ degree), π ± , π degree production at large x F , and Δσ L (pp, bar pp) measurements. 18 refs

  14. Examining the volume efficiency of the cortical architecture in a multi-processor network model.

    Science.gov (United States)

    Ruppin, E; Schwartz, E L; Yeshurun, Y

    1993-01-01

    The convoluted form of the sheet-like mammalian cortex naturally raises the question whether there is a simple geometrical reason for the prevalence of cortical architecture in the brains of higher vertebrates. Addressing this question, we present a formal analysis of the volume occupied by a massively connected network or processors (neurons) and then consider the pertaining cortical data. Three gross macroscopic features of cortical organization are examined: the segregation of white and gray matter, the circumferential organization of the gray matter around the white matter, and the folded cortical structure. Our results testify to the efficiency of cortical architecture.

  15. Defects in cortical microarchitecture among African-American women with type 2 diabetes.

    Science.gov (United States)

    Yu, E W; Putman, M S; Derrico, N; Abrishamanian-Garcia, G; Finkelstein, J S; Bouxsein, M L

    2015-02-01

    Patients with type 2 diabetes mellitus (DM2) have increased fracture risk. We found that African-American women with DM2 have increased cortical porosity and lower cortical bone density at the radius than non-diabetic controls. These cortical deficits are associated with hyperglycemia and may contribute to skeletal fragility associated with DM2. Fracture risk is increased in patients with type 2 diabetes mellitus (DM2) despite normal areal bone mineral density (aBMD). DM2 is more common in African-Americans than in Caucasians. It is not known whether African-American women with DM2 have deficits in bone microstructure. We measured aBMD at the spine and hip by DXA, and volumetric BMD (vBMD) and microarchitecture at the distal radius and tibia by HR-pQCT in 22 DM2 and 78 non-diabetic African-American women participating in the Study of Women Across the Nation (SWAN). We also measured fasting glucose and HOMA-IR. Age, weight, and aBMD at all sites were similar in both groups. At the radius, cortical porosity was 26% greater, while cortical vBMD and tissue mineral density were lower in women with DM2 than in controls. There were no differences in radius total vBMD or trabecular vBMD between groups. Despite inferior cortical bone properties at the radius, FEA-estimated failure load was similar between groups. Tibia vBMD and microarchitecture were also similar between groups. There were no significant associations between cortical parameters and duration of DM2 or HOMA-IR. However, among women with DM2, higher fasting glucose levels were associated with lower cortical vBMD (r=-0.54, p=0.018). DM2 and higher fasting glucose are associated with unfavorable cortical bone microarchitecture at the distal radius in African-American women. These structural deficits may contribute to the increased fracture risk among women with DM2. Further, our results suggest that hyperglycemia may be involved in mechanisms of skeletal fragility associated with DM2.

  16. Recent advance in polar seismology: Global impact of the International Polar Year

    Science.gov (United States)

    Kanao, Masaki; Zhao, Dapeng; Wiens, Douglas A.; Stutzmann, Éléonore

    2015-03-01

    The most exciting initiative for the recent polar studies was the International Polar Year (IPY) in 2007-2008. The IPY has witnessed a growing community of seismologists who have made considerable efforts to acquire high-quality data in polar regions. It also provided an excellent opportunity to make significant advances in seismic instrumentation of the polar regions to achieve scientific targets involving global issues. Taking these aspects into account, we organize and publish a special issue in Polar Science on the recent advance in polar seismology and cryoseismology as fruitful achievements of the IPY.

  17. Cortical spreading depression in migraine-time to reconsider?

    Directory of Open Access Journals (Sweden)

    Alan J McComas

    2015-08-01

    Full Text Available New evidence concerning the pathophysiology of migraine has come from the results of therapeutic transcranial magnetic stimulation (tTMS. The instantaneous responses to single pulses applied during the aura or headache phase, together with a number of other observations, make it unlikely that cortical spreading depression is involved in migraine. tTMS is considered to act by abolishing abnormal impulse activity in cortical pyramidal neurons and a suggestion is made as to how this activity could arise.

  18. An adhesome comprising laminin, dystroglycan and myosin IIA is required during notochord development in Xenopus laevis.

    Science.gov (United States)

    Buisson, Nicolas; Sirour, Cathy; Moreau, Nicole; Denker, Elsa; Le Bouffant, Ronan; Goullancourt, Aline; Darribère, Thierry; Bello, Valérie

    2014-12-01

    Dystroglycan (Dg) is a transmembrane receptor for laminin that must be expressed at the right time and place in order to be involved in notochord morphogenesis. The function of Dg was examined in Xenopus laevis embryos by knockdown of Dg and overexpression and replacement of the endogenous Dg with a mutated form of the protein. This analysis revealed that Dg is required for correct laminin assembly, for cell polarization during mediolateral intercalation and for proper differentiation of vacuoles. Using mutations in the cytoplasmic domain, we identified two sites that are involved in cell polarization and are required for mediolateral cell intercalation, and a site that is required for vacuolation. Furthermore, using a proteomic analysis, the cytoskeletal non-muscle myosin IIA has been identified for the first time as a molecular link between the Dg-cytoplasmic domain and cortical actin. The data allowed us to identify the adhesome laminin-Dg-myosin IIA as being required to maintain the cortical actin cytoskeleton network during vacuolation, which is crucial to maintain the shape of notochordal cells. © 2014. Published by The Company of Biologists Ltd.

  19. Study of excess carrier dynamics in polar, semi-polar, and non-polar (In,Ga)N epilayers and QWs

    Energy Technology Data Exchange (ETDEWEB)

    Aleksiejunas, R. [Institute of Applied Research, Vilnius University, Sauletekio Ave. 9-III, 10222 Vilnius (Lithuania); Laser Research Center, Vilnius University, Sauletekio Ave. 10, 10222 Vilnius (Lithuania); Lubys, L.; Jarasiunas, K. [Institute of Applied Research, Vilnius University, Sauletekio Ave. 9-III, 10222 Vilnius (Lithuania); Vengris, M. [Laser Research Center, Vilnius University, Sauletekio Ave. 10, 10222 Vilnius (Lithuania); Wernicke, T.; Hoffmann, V.; Netzel, C.; Knauer, A.; Weyers, M. [Ferdinand-Braun-Institut, Leibniz-Institut fuer Hoechstfrequenztechnik, Gustav-Kirchhoff-Str. 4, 12498 Berlin (Germany); Kneissl, M. [Ferdinand-Braun-Institut, Leibniz-Institut fuer Hoechstfrequenztechnik, Gustav-Kirchhoff-Str. 4, 12498 Berlin (Germany); Institute of Solid State Physics, Technische Universitaet Berlin, Hardenbergstr. 36, 10623 Berlin (Germany)

    2011-07-15

    We studied carrier recombination and diffusion in GaN/sapphire templates, (In,Ga)N layers, and (In,Ga)N quantum well structures oriented along the polar [0001], semi-polar [11-22], and non-polar [11-20] orientations by means of light induced transient grating, differential transmission, and photoluminescence optical techniques. We show that the lifetime of excess carriers drops by orders of magnitude when changing the orientation from polar to non-polar, both in GaN templates and (In,Ga)N layers. We attribute the shorter lifetime to carrier trapping by extended structural defects that are more abundant in non-polar grown samples. In addition, we observe pronounced carrier localization effects in the semi- and non-polar layers. We show that thick (In,Ga)N layers inherit the properties of the GaN templates. However, the thin quantum well structures show a lower carrier trapping activity. So, a better electrical quality can be assumed as compared to the thick (In,Ga)N layers. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  20. Traumatic Brain Injury Increases Cortical Glutamate Network Activity by Compromising GABAergic Control.

    Science.gov (United States)

    Cantu, David; Walker, Kendall; Andresen, Lauren; Taylor-Weiner, Amaro; Hampton, David; Tesco, Giuseppina; Dulla, Chris G

    2015-08-01

    Traumatic brain injury (TBI) is a major risk factor for developing pharmaco-resistant epilepsy. Although disruptions in brain circuitry are associated with TBI, the precise mechanisms by which brain injury leads to epileptiform network activity is unknown. Using controlled cortical impact (CCI) as a model of TBI, we examined how cortical excitability and glutamatergic signaling was altered following injury. We optically mapped cortical glutamate signaling using FRET-based glutamate biosensors, while simultaneously recording cortical field potentials in acute brain slices 2-4 weeks following CCI. Cortical electrical stimulation evoked polyphasic, epileptiform field potentials and disrupted the input-output relationship in deep layers of CCI-injured cortex. High-speed glutamate biosensor imaging showed that glutamate signaling was significantly increased in the injured cortex. Elevated glutamate responses correlated with epileptiform activity, were highest directly adjacent to the injury, and spread via deep cortical layers. Immunoreactivity for markers of GABAergic interneurons were significantly decreased throughout CCI cortex. Lastly, spontaneous inhibitory postsynaptic current frequency decreased and spontaneous excitatory postsynaptic current increased after CCI injury. Our results suggest that specific cortical neuronal microcircuits may initiate and facilitate the spread of epileptiform activity following TBI. Increased glutamatergic signaling due to loss of GABAergic control may provide a mechanism by which TBI can give rise to post-traumatic epilepsy. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  1. Mitochondrial dysfunction precedes depression of AMPK/AKT signaling in insulin resistance induced by high glucose in primary cortical neurons.

    Science.gov (United States)

    Peng, Yunhua; Liu, Jing; Shi, Le; Tang, Ying; Gao, Dan; Long, Jiangang; Liu, Jiankang

    2016-06-01

    Recent studies have demonstrated brain insulin signaling impairment and mitochondrial dysfunction in diabetes. Hyperinsulinemia and hyperlipidemia arising from diabetes have been linked to neuronal insulin resistance, and hyperglycemia induces peripheral sensory neuronal impairment and mitochondrial dysfunction. However, how brain glucose at diabetic conditions elicits cortical neuronal insulin signaling impairment and mitochondrial dysfunction remains unknown. In the present study, we cultured primary cortical neurons with high glucose levels and investigated the neuronal mitochondrial function and insulin response. We found that mitochondrial function was declined in presence of 10 mmol/L glucose, prior to the depression of AKT signaling in primary cortical neurons. We further demonstrated that the cerebral cortex of db/db mice exhibited both insulin resistance and loss of mitochondrial complex components. Moreover, we found that adenosine monophosphate-activated protein kinase (AMPK) inactivation is involved in high glucose-induced mitochondrial dysfunction and insulin resistance in primary cortical neurons and neuroblastoma cells, as well as in cerebral cortex of db/db mice, and all these impairments can be rescued by mitochondrial activator, resveratrol. Taken together, our results extend the finding that high glucose (≥10 mmol/L) comparable to diabetic brain extracellular glucose level leads to neuronal mitochondrial dysfunction and resultant insulin resistance, and targeting mitochondria-AMPK signaling might be a promising strategy to protect against diabetes-related neuronal impairment in central nerves system. We found that high glucose (≥10 mmol/L), comparable to diabetic brain extracellular glucose level, leads to neuronal mitochondrial dysfunction and resultant insulin resistance in an AMPK-dependent manner, and targeting mitochondria-AMPK signaling might be a promising strategy to protect against diabetes-related neuronal impairment in central

  2. A neural model of motion processing and visual navigation by cortical area MST.

    Science.gov (United States)

    Grossberg, S; Mingolla, E; Pack, C

    1999-12-01

    Cells in the dorsal medial superior temporal cortex (MSTd) process optic flow generated by self-motion during visually guided navigation. A neural model shows how interactions between well-known neural mechanisms (log polar cortical magnification, Gaussian motion-sensitive receptive fields, spatial pooling of motion-sensitive signals and subtractive extraretinal eye movement signals) lead to emergent properties that quantitatively simulate neurophysiological data about MSTd cell properties and psychophysical data about human navigation. Model cells match MSTd neuron responses to optic flow stimuli placed in different parts of the visual field, including position invariance, tuning curves, preferred spiral directions, direction reversals, average response curves and preferred locations for stimulus motion centers. The model shows how the preferred motion direction of the most active MSTd cells can explain human judgments of self-motion direction (heading), without using complex heading templates. The model explains when extraretinal eye movement signals are needed for accurate heading perception, and when retinal input is sufficient, and how heading judgments depend on scene layouts and rotation rates.

  3. Polarized targets and beams

    International Nuclear Information System (INIS)

    Meyer, W.

    1985-01-01

    First the experimental situation of the single-pion photoproduction and the photodisintegration of the deuteron is briefly discussed. Then a description of the Bonn polarization facilities is given. The point of main effort is put on the polarized target which plays a vital role in the program. A facility for photon induced double polarization experiments at ELSA will be presented in section 4. Properties of a tensor polarized deuteron target are discussed in section 5. The development in the field of polarized targets, especially on new target materials, enables a new generation of polarized target experiments with (polarized) electrons. Some comments on the use of a polarized target in combination with electron beams will be discussed in section 6. Electron deuteron scattering from a tensor polarized deuteron target is considered and compared with other experimental possibilities. (orig./HSI)

  4. Alterations of whole-brain cortical area and thickness in mild cognitive impairment and Alzheimer's disease.

    Science.gov (United States)

    Li, Chuanming; Wang, Jian; Gui, Li; Zheng, Jian; Liu, Chen; Du, Hanjian

    2011-01-01

    Gray matter volume and density of several brain regions, determined by magnetic resonance imaging (MRI), are decreased in Alzheimer's disease (AD). Animal studies have indicated that changes in cortical area size is relevant to thinking and behavior, but alterations of cortical area and thickness in the brains of individuals with AD or its likely precursor, mild cognitive impairment (MCI), have not been reported. In this study, 25 MCI subjects, 30 AD subjects, and 30 age-matched normal controls were recruited for brain MRI scans and Functional Activities Questionnaire (FAQ) assessments. Based on the model using FreeSurfer software, two brain lobes were divided into various regions according to the Desikan-Killiany atlas and the cortical area and thickness of every region was compared and analyzed. We found a significant increase in cortical area of several regions in the frontal and temporal cortices, which correlated negatively with MMSE scores, and a significant decrease in cortical area of several regions in the parietal cortex and the cingulate gyrus in AD subjects. Increased cortical area was also seen in some regions of the frontal and temporal cortices in MCI subjects, whereas the cortical thickness of the same regions was decreased. Our observations suggest characteristic differences of the cortical area and thickness in MCI, AD, and normal control subjects, and these changes may help diagnose both MCI and AD.

  5. GDNF/GFRα1 Complex Abrogates Self-Renewing Activity of Cortical Neural Precursors Inducing Their Differentiation

    Directory of Open Access Journals (Sweden)

    Antonela Bonafina

    2018-03-01

    Full Text Available Summary: The balance between factors leading to proliferation and differentiation of cortical neural precursors (CNPs determines the correct cortical development. In this work, we show that GDNF and its receptor GFRα1 are expressed in the neocortex during the period of cortical neurogenesis. We show that the GDNF/GFRα1 complex inhibits the self-renewal capacity of mouse CNP cells induced by fibroblast growth factor 2 (FGF2, promoting neuronal differentiation. While GDNF leads to decreased proliferation of cultured cortical precursor cells, ablation of GFRα1 in glutamatergic cortical precursors enhances its proliferation. We show that GDNF treatment of CNPs promoted morphological differentiation even in the presence of the self-renewal-promoting factor, FGF2. Analysis of GFRα1-deficient mice shows an increase in the number of cycling cells during cortical development and a reduction in dendrite development of cortical GFRα1-expressing neurons. Together, these results indicate that GDNF/GFRα1 signaling plays an essential role in regulating the proliferative condition and the differentiation of cortical progenitors. : In this article, Ledda and colleagues show that GDNF acting through its receptor GFRα1 plays a critical role in the maturation of cortical progenitors by counteracting FGF2 self-renewal activity on neural stem cells and promoting neuronal differentiation. Keywords: GDNF, GFRα1, cortical precursors, proliferation, postmitotic neurons, neuronal differentiation

  6. High-conductance states in a mean-field cortical network model

    CERN Document Server

    Lerchner, A; Hertz, J

    2004-01-01

    Measured responses from visual cortical neurons show that spike times tend to be correlated rather than exactly Poisson distributed. Fano factors vary and are usually greater than 1 due to the tendency of spikes being clustered into bursts. We show that this behavior emerges naturally in a balanced cortical network model with random connectivity and conductance-based synapses. We employ mean field theory with correctly colored noise to describe temporal correlations in the neuronal activity. Our results illuminate the connection between two independent experimental findings: high conductance states of cortical neurons in their natural environment, and variable non-Poissonian spike statistics with Fano factors greater than 1.

  7. Glycine Receptor α2 Subunit Activation Promotes Cortical Interneuron Migration

    Directory of Open Access Journals (Sweden)

    Ariel Avila

    2013-08-01

    Full Text Available Glycine receptors (GlyRs are detected in the developing CNS before synaptogenesis, but their function remains elusive. This study demonstrates that functional GlyRs are expressed by embryonic cortical interneurons in vivo. Furthermore, genetic disruption of these receptors leads to interneuron migration defects. We discovered that extrasynaptic activation of GlyRs containing the α2 subunit in cortical interneurons by endogenous glycine activates voltage-gated calcium channels and promotes calcium influx, which further modulates actomyosin contractility to fine-tune nuclear translocation during migration. Taken together, our data highlight the molecular events triggered by GlyR α2 activation that control cortical tangential migration during embryogenesis.

  8. Altered cortical anatomical networks in temporal lobe epilepsy

    Science.gov (United States)

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

    2011-03-01

    Temporal lobe epilepsy (TLE) is one of the most common epilepsy syndromes with focal seizures generated in the left or right temporal lobes. With the magnetic resonance imaging (MRI), many evidences have demonstrated that the abnormalities in hippocampal volume and the distributed atrophies in cortical cortex. However, few studies have investigated if TLE patients have the alternation in the structural networks. In the present study, we used the cortical thickness to establish the morphological connectivity networks, and investigated the network properties using the graph theoretical methods. We found that all the morphological networks exhibited the small-world efficiency in left TLE, right TLE and normal groups. And the betweenness centrality analysis revealed that there were statistical inter-group differences in the right uncus region. Since the right uncus located at the right temporal lobe, these preliminary evidences may suggest that there are topological alternations of the cortical anatomical networks in TLE, especially for the right TLE.

  9. Reduction of coating induced polarization aberrations by controlling the polarization state variation

    International Nuclear Information System (INIS)

    Li, Yanghui; Shen, Weidong; Zheng, Zhenrong; Zhang, Yueguang; Liu, Xu; Hao, Xiang

    2011-01-01

    The mechanism of coating induced polarization state variation is analysed by the Jones matrix. Pauli spin matrices are used to establish the relationship between coating induced polarization state variation and polarization aberrations. To reduce coating induced polarization aberrations, we propose that δ = 0 and T s = T p at arbitrary incident angle should be appended as two additional optimization goals of optical coating design when the requirements of transmittance are met. Two typical anti-reflection (AR) coatings are designed and the polarization state variation induced by them is simulated. The MTF (modulation transfer function) calculated by polarization ray tracing is applied to evaluate the polarization aberrations of the practical lithography objective system with the two AR coatings. All the obtained results show that the coating induced polarization aberrations can be reduced by optimizing the angle dependent properties of the optical coating without additional optical elements

  10. Effect of 3D Polarization profiles on polarization measurements and colliding beam experiments

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, W.; Bazilevsky, A.

    2011-08-18

    The development of polarization profiles are the primary reason for the loss of average polarization. Polarization profiles have been parametrized with a Gaussian distribution. We derive the effect of 3-dimensional polarization profiles on the measured polarization in polarimeters, as well as the observed polarization and the figure of merit in single and double spin experiments. Examples from RHIC are provided. The Relativistic Heavy Ion Collider (RHIC) is the only collider of spin polarized protons. During beam acceleration and storage profiles of the polarization P develop, which affect the polarization measured in a polarimeter, and the polarization and figure of merit (FOM) in colliding beam experiments. We calculate these for profiles in all dimensions, and give examples for RHIC. Like in RHIC we call the two colliding beams Blue and Yellow. We use the overbar to designate intensity-weighted averages in polarimeters (e.g. {bar P}), and angle brackets to designate luminosity-weighted averages in colliding beam experiments (e.g.

    ).

  11. Effect of 3D Polarization profiles on polarization measurements and colliding beam experiments

    International Nuclear Information System (INIS)

    Fischer, W.; Bazilevsky, A.

    2011-01-01

    The development of polarization profiles are the primary reason for the loss of average polarization. Polarization profiles have been parametrized with a Gaussian distribution. We derive the effect of 3-dimensional polarization profiles on the measured polarization in polarimeters, as well as the observed polarization and the figure of merit in single and double spin experiments. Examples from RHIC are provided. The Relativistic Heavy Ion Collider (RHIC) is the only collider of spin polarized protons. During beam acceleration and storage profiles of the polarization P develop, which affect the polarization measured in a polarimeter, and the polarization and figure of merit (FOM) in colliding beam experiments. We calculate these for profiles in all dimensions, and give examples for RHIC. Like in RHIC we call the two colliding beams Blue and Yellow. We use the overbar to designate intensity-weighted averages in polarimeters (e.g. (bar P)), and angle brackets to designate luminosity-weighted averages in colliding beam experiments (e.g. ).

  12. Tactile thermal oral stimulation increases the cortical representation of swallowing

    Directory of Open Access Journals (Sweden)

    Suntrup Sonja

    2009-06-01

    Full Text Available Abstract Background Dysphagia is a leading complication in stroke patients causing aspiration pneumonia, malnutrition and increased mortality. Current strategies of swallowing therapy involve on the one hand modification of eating behaviour or swallowing technique and on the other hand facilitation of swallowing with the use of pharyngeal sensory stimulation. Thermal tactile oral stimulation (TTOS is an established method to treat patients with neurogenic dysphagia especially if caused by sensory deficits. Little is known about the possible mechanisms by which this interventional therapy may work. We employed whole-head MEG to study changes in cortical activation during self-paced volitional swallowing in fifteen healthy subjects with and without TTOS. Data were analyzed by means of synthetic aperture magnetometry (SAM and the group analysis of individual SAM data was performed using a permutation test. Results Compared to the normal swallowing task a significantly increased bilateral cortical activation was seen after oropharyngeal stimulation. Analysis of the chronological changes during swallowing suggests facilitation of both the oral and the pharyngeal phase of deglutition. Conclusion In the present study functional cortical changes elicited by oral sensory stimulation could be demonstrated. We suggest that these results reflect short-term cortical plasticity of sensory swallowing areas. These findings facilitate our understanding of the role of cortical reorganization in dysphagia treatment and recovery.

  13. Nuclear polarization and neutrons

    International Nuclear Information System (INIS)

    Glaettli, H.

    1985-01-01

    Different possibilities for the use of polarized nuclei in thermal neutron scattering on condensed matter are reviewed. Highly polarized nuclei are the starting point for studying dipolar magnetic order. Systematic measurement of spin-dependent scattering lengths is possible on samples with polarized nuclei. Highly polarized hydrogen should help to unravel complicated structures in chemistry and biology. The use of polarized proton targets as an energy-independent neutron polarizer in the thermal and epithermal region should be considered afresh. (author)

  14. Intra-operative multi-site stimulation: Expanding methodology for cortical brain mapping of language functions.

    Science.gov (United States)

    Gonen, Tal; Gazit, Tomer; Korn, Akiva; Kirschner, Adi; Perry, Daniella; Hendler, Talma; Ram, Zvi

    2017-01-01

    Direct cortical stimulation (DCS) is considered the gold-standard for functional cortical mapping during awake surgery for brain tumor resection. DCS is performed by stimulating one local cortical area at a time. We present a feasibility study using an intra-operative technique aimed at improving our ability to map brain functions which rely on activity in distributed cortical regions. Following standard DCS, Multi-Site Stimulation (MSS) was performed in 15 patients by applying simultaneous cortical stimulations at multiple locations. Language functioning was chosen as a case-cognitive domain due to its relatively well-known cortical organization. MSS, performed at sites that did not produce disruption when applied in a single stimulation point, revealed additional language dysfunction in 73% of the patients. Functional regions identified by this technique were presumed to be significant to language circuitry and were spared during surgery. No new neurological deficits were observed in any of the patients following surgery. Though the neuro-electrical effects of MSS need further investigation, this feasibility study may provide a first step towards sophistication of intra-operative cortical mapping.

  15. Right temporal cortical hypertrophy in resilience to trauma: an MRI study

    Directory of Open Access Journals (Sweden)

    André Sevenius Nilsen

    2016-07-01

    Full Text Available Background: In studies employing physiological measures such as magnetic resonance imaging (MRI, it is often hard to distinguish what constitutes risk-resilience factors to posttraumatic stress disorder (PTSD following trauma exposure and what the effects of trauma exposure and PTSD are. Objective: We aimed to investigate whether there were observable morphological differences in cortical and sub-cortical regions of the brain, 7–8 years after a single potentially traumatic event. Methods: Twenty-four participants, who all directly experienced the 2004 Indian Ocean Tsunami, and 25 controls, underwent structural MRI using a 3T scanner. We generated cortical thickness maps and parcellated sub-cortical volumes for analysis. Results: We observed greater cortical thickness for the trauma-exposed participants relative to controls, in a right lateralized temporal lobe region including anterior fusiform gyrus, and superior, middle, and inferior temporal gyrus. Conclusions: We observed greater thickness in the right temporal lobe which might indicate that the region could be implicated in resilience to the long-term effects of a traumatic event. We hypothesize this is due to altered emotional semantic memory processing. However, several methodological and confounding issues warrant caution in interpretation of the results.

  16. Right temporal cortical hypertrophy in resilience to trauma: an MRI study.

    Science.gov (United States)

    Nilsen, André Sevenius; Hilland, Eva; Kogstad, Norunn; Heir, Trond; Hauff, Edvard; Lien, Lars; Endestad, Tor

    2016-01-01

    In studies employing physiological measures such as magnetic resonance imaging (MRI), it is often hard to distinguish what constitutes risk-resilience factors to posttraumatic stress disorder (PTSD) following trauma exposure and what the effects of trauma exposure and PTSD are. We aimed to investigate whether there were observable morphological differences in cortical and sub-cortical regions of the brain, 7-8 years after a single potentially traumatic event. Twenty-four participants, who all directly experienced the 2004 Indian Ocean Tsunami, and 25 controls, underwent structural MRI using a 3T scanner. We generated cortical thickness maps and parcellated sub-cortical volumes for analysis. We observed greater cortical thickness for the trauma-exposed participants relative to controls, in a right lateralized temporal lobe region including anterior fusiform gyrus, and superior, middle, and inferior temporal gyrus. We observed greater thickness in the right temporal lobe which might indicate that the region could be implicated in resilience to the long-term effects of a traumatic event. We hypothesize this is due to altered emotional semantic memory processing. However, several methodological and confounding issues warrant caution in interpretation of the results.

  17. Long-distance swimming by polar bears (Ursus maritimus) of the southern Beaufort Sea during years of extensive open water

    Science.gov (United States)

    2014-01-01

    Polar bears (Ursus maritimus Phipps, 1774) depend on sea ice for catching marine mammal prey. Recent sea-ice declines have been linked to reductions in body condition, survival, and population size. Reduced foraging opportunity is hypothesized to be the primary cause of sea-ice-linked declines, but the costs of travel through a deteriorated sea-ice environment also may be a factor. We used movement data from 52 adult female polar bears wearing Global Positioning System (GPS) collars, including some with dependent young, to document long-distance swimming (>50 km) by polar bears in the southern Beaufort and Chukchi seas. During 6 years (2004-2009), we identified 50 long-distance swims by 20 bears. Swim duration and distance ranged from 0.7 to 9.7 days (mean = 3.4 days) and 53.7 to 687.1 km (mean = 154.2 km), respectively. Frequency of swimming appeared to increase over the course of the study. We show that adult female polar bears and their cubs are capable of swimming long distances during periods when extensive areas of open water are present. However, long-distance swimming appears to have higher energetic demands than moving over sea ice. Our observations suggest long-distance swimming is a behavioral response to declining summer sea-ice conditions.

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

    Science.gov (United States)

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

    2015-10-01

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

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

    Directory of Open Access Journals (Sweden)

    Omer Ziv

    2015-10-01

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

  20. NUCLEON POLARIZATION IN 3-BODY MODELS OF POLARIZED LI-6

    NARCIS (Netherlands)

    SCHELLINGERHOUT, NW; KOK, LP; COON, SA; ADAM, RM

    1993-01-01

    Just as He-3 --> can be approximately characterized as a polarized neutron target, polarized Li-6D has been advocated as a good isoscalar nuclear target for the extraction of the polarized gluon content of the nucleon. The original argument rests upon a presumed ''alpha + deuteron'' picture of Li-6,