WorldWideScience

Sample records for ca1 pyramidal cells

  1. Signal Propagation in Oblique Dendrites of CA1 Pyramidal Cells

    OpenAIRE

    Migliore, Michele; Ferrante, Michele; Ascoli, Giorgio A.

    2005-01-01

    The electrophysiological properties of the oblique branches of CA1 pyramidal neurons are largely unknown and very difficult to investigate experimentally. These relatively thin dendrites make up the majority of the apical tree surface area and constitute the main target of Schaffer collateral axons from CA3. Their electrogenic properties might have an important role in defining the computational functions of CA1 neurons. It is thus important to determine if and to what extent the back- and fo...

  2. Novel nootropic dipeptide Noopept increases inhibitory synaptic transmission in CA1 pyramidal cells.

    Science.gov (United States)

    Kondratenko, Rodion V; Derevyagin, Vladimir I; Skrebitsky, Vladimir G

    2010-05-31

    Effects of newly synthesized nootropic and anxiolytic dipeptide Noopept on inhibitory synaptic transmission in hippocampal CA1 pyramidal cells were investigated using patch-clamp technique in whole-cell configuration. Bath application of Noopept (1 microM) significantly increased the frequency of spike-dependant spontaneous IPSCs whereas spike-independent mIPSCs remained unchanged. It was suggested that Noopept mediates its effect due to the activation of inhibitory interneurons terminating on CA1 pyramidal cells. Results of current clamp recording of inhibitory interneurons residing in stratum radiatum confirmed this suggestion. PMID:20382202

  3. Serotonin3 receptor agonists attenuate glutamate-induced firing in rat hippocampal CA1 pyramidal cells.

    Science.gov (United States)

    Zhang, J Y; Zeise, M L; Wang, R Y

    1994-01-01

    The techniques of extracellular single cell recording and microiontophoresis were used to study the effect of 5-HT3 receptor agonists on glutamate-activated firing of CA1 hippocampal pyramidal cells. Iontophoretic application of 5-HT3 receptor agonists 2-methyl-5-HT and SR 57227A produced a current (dose)-dependent suppression of the firing of CA1 pyramidal cells; SR 57227A was more effective than 2-methyl-5-HT. The suppressant action of 2-methyl-5-HT and SR 57227A had a slow onset and showed little or no desensitization. This effect was markedly attenuated or completely blocked by the 5-HT3 receptor antagonist BRL 46470A but not by the nonspecific 5-HT1 and 5-HT2 receptor antagonist metergoline or by the 5-HT1A antagonist WAY 100478. Intravenous administration of SR 57227A was effective in reducing the firing rate of CA1 pyramidal cells and this effect was prevented by BRL 46470A administered either i.v. or iontophoretically. Iontophoresis of 2-methyl-5-HT also diminished CA1 postsynaptic field potentials evoked by electrical stimulation of the Schaffer collaterals. Again, BRL 46470A but not metergoline prevented the suppressant action of 2-methyl-5-HT. Taken together, our results indicate that activation of 5-HT3-like receptors in the hippocampal CA1 region effectively reduces the efficacy of glutamatergic neurotransmission. PMID:7984287

  4. Somatosensory stimulation suppresses the excitability of pyramidal cells in the hippocampal CA1 region in rats

    Institute of Scientific and Technical Information of China (English)

    Yang Wang; Zhouyan Feng; Jing Wang; Xiaojing Zheng

    2014-01-01

    The hippocampal region of the brain is important for encoding environment inputs and memory formation. However, the underlying mechanisms are unclear. To investigate the behavior of indi-vidual neurons in response to somatosensory inputs in the hippocampal CA1 region, we recorded and analyzed changes in local ifeld potentials and the ifring rates of individual pyramidal cells and interneurons during tail clamping in urethane-anesthetized rats. We also explored the mechanisms underlying the neuronal responses. Somatosensory stimulation, in the form of tail clamping, chan-ged local ifeld potentials into theta rhythm-dominated waveforms, decreased the spike ifring of py-ramidal cells, and increased interneuron ifring. In addition, somatosensory stimulation attenuated orthodromic-evoked population spikes. These results suggest that somatosensory stimulation sup-presses the excitability of pyramidal cells in the hippocampal CA1 region. Increased inhibition by local interneurons might underlie this effect. These ifndings provide insight into the mechanisms of signal processing in the hippocampus and suggest that sensory stimulation might have thera-peutic potential for brain disorders associated with neuronal hyperexcitability.

  5. Structured Dendritic Inhibition Supports Branch-Selective Integration in CA1 Pyramidal Cells.

    Science.gov (United States)

    Bloss, Erik B; Cembrowski, Mark S; Karsh, Bill; Colonell, Jennifer; Fetter, Richard D; Spruston, Nelson

    2016-03-01

    Neuronal circuit function is governed by precise patterns of connectivity between specialized groups of neurons. The diversity of GABAergic interneurons is a hallmark of cortical circuits, yet little is known about their targeting to individual postsynaptic dendrites. We examined synaptic connectivity between molecularly defined inhibitory interneurons and CA1 pyramidal cell dendrites using correlative light-electron microscopy and large-volume array tomography. We show that interneurons can be highly selective in their connectivity to specific dendritic branch types and, furthermore, exhibit precisely targeted connectivity to the origin or end of individual branches. Computational simulations indicate that the observed subcellular targeting enables control over the nonlinear integration of synaptic input or the initiation and backpropagation of action potentials in a branch-selective manner. Our results demonstrate that connectivity between interneurons and pyramidal cell dendrites is more precise and spatially segregated than previously appreciated, which may be a critical determinant of how inhibition shapes dendritic computation. VIDEO ABSTRACT. PMID:26898780

  6. GABABR-Dependent Long-Term Depression at Hippocampal Synapses between CB1-Positive Interneurons and CA1 Pyramidal Cells.

    Science.gov (United States)

    Jappy, Dave; Valiullina, Fliza; Draguhn, Andreas; Rozov, Andrei

    2016-01-01

    Activity induced long lasting modifications of synaptic efficacy have been extensively studied in excitatory synapses, however, long term plasticity is also a property of inhibitory synapses. Inhibitory neurons in the hippocampal CA1 region can be subdivided according to the compartment they target on the pyramidal cell. Some interneurons preferentially innervate the perisomatic area and axon hillock of the pyramidal cells while others preferentially target dendritic branches and spines. Another characteristic feature allowing functional classification of interneurons is cell type specific expression of different neurochemical markers and receptors. In the hippocampal CA1 region, nearly 90% of the interneurons expressing cannabinoid type 1 receptors (CB1R) also express cholecystokinin (CCK). Therefore, the functional presence of CB1 receptors can be used for identification of the inhibitory input from CCK positive (CCK+) interneurons to CA1 pyramidal cells. The goal of this study was to explore the nature of long term plasticity at the synapses between interneurons expressing CB1Rs (putative CCK+) and pyramidal neurons in the CA1 region of the hippocampus in vitro. We found that theta burst stimulation triggered robust long-term depression (LTD) at this synapse. The locus of LTD induction was postsynaptic and required activation of GABAB receptors. We also showed that LTD at this synaptic connection involves GABABR-dependent suppression of adenylyl cyclase and consequent reduction of PKA activity. In this respect, CB1+ to pyramidal cell synapses differ from the majority of the other hippocampal inhibitory connections where theta burst stimulation results in long-term potentiation. PMID:26858602

  7. Characterization of altered intrinsic excitability in hippocampal CA1 pyramidal cells of the Aβ-overproducing PDAPP mouse☆

    Science.gov (United States)

    Kerrigan, T.L.; Brown, J.T.; Randall, A.D.

    2014-01-01

    Transgenic mice that accumulate Aβ peptides in the CNS are commonly used to interrogate functional consequences of Alzheimer's disease-associated amyloidopathy. In addition to changes to synaptic function, there is also growing evidence that changes to intrinsic excitability of neurones can arise in these models of amyloidopathy. Furthermore, some of these alterations to intrinsic properties may occur relatively early within the age-related progression of experimental amyloidopathy. Here we report a detailed comparison between the intrinsic excitability properties of hippocampal CA1 pyramidal neurones in wild-type (WT) and PDAPP mice. The latter is a well-established model of Aβ accumulation which expresses human APP harbouring the Indiana (V717F) mutation. At the age employed in this study (9–10 months) CNS Abeta was elevated in PDAPP mice but significant plaque pathology was absent. PDAPP mice exhibited no differences in subthreshold intrinsic properties including resting potential, input resistance, membrane time constant and sag. When CA1 cells of PDAPP mice were given depolarizing stimuli of various amplitudes they initially fired at a higher frequency than WT cells. Commensurate with this, PDAPP cells exhibited a larger fast afterdepolarizing potential. PDAPP mice had narrower spikes but action potential threshold, rate of rise and peak were not different. Thus not all changes seen in our previous studies of amyloidopathy models were present in PDAPP mice; however, narrower spikes, larger ADPs and the propensity to fire at higher frequencies were consistent with our prior work and thus may represent robust, cross-model, indices of amyloidopathy. This article is part of a Special Issue entitled ‘Neurodevelopment Disorder’. PMID:24055500

  8. Transcriptome analysis of the hippocampal CA1 pyramidal cell region after kainic acid-induced status epilepticus in juvenile rats.

    Directory of Open Access Journals (Sweden)

    Hanna B Laurén

    Full Text Available Molecular mechanisms involved in epileptogenesis in the developing brain remain poorly understood. The gene array approach could reveal some of the factors involved by allowing the identification of a broad scale of genes altered by seizures. In this study we used microarray analysis to reveal the gene expression profile of the laser microdissected hippocampal CA1 subregion one week after kainic acid (KA-induced status epilepticus (SE in 21-day-old rats, which are developmentally roughly comparable to juvenile children. The gene expression analysis with the Chipster software generated a total of 1592 differently expressed genes in the CA1 subregion of KA-treated rats compared to control rats. The KEGG database revealed that the identified genes were involved in pathways such as oxidative phosporylation (26 genes changed, and long-term potentiation (LTP; 18 genes changed. Also genes involved in Ca(2+ homeostasis, gliosis, inflammation, and GABAergic transmission were altered. To validate the microarray results we further examined the protein expression for a subset of selected genes, glial fibrillary protein (GFAP, apolipoprotein E (apo E, cannabinoid type 1 receptor (CB1, Purkinje cell protein 4 (PEP-19, and interleukin 8 receptor (CXCR1, with immunohistochemistry, which confirmed the transcriptome results. Our results showed that SE resulted in no obvious CA1 neuronal loss, and alterations in the expression pattern of several genes during the early epileptogenic phase were comparable to previous gene expression studies of the adult hippocampus of both experimental epileptic animals and patients with temporal lobe epilepsy (TLE. However, some changes seem to occur after SE specifically in the juvenile rat hippocampus. Insight of the SE-induced alterations in gene expression and their related pathways could give us hints for the development of new target-specific antiepileptic drugs that interfere with the progression of the disease in the

  9. Altered calcium metabolism in aging CA1 hippocampal pyramidal neurons

    OpenAIRE

    Oh, M. Matthew; Oliveira, Fernando A.; Waters, Jack; Disterhoft, John F.

    2013-01-01

    Altered neuronal calcium homeostasis is widely hypothesized to underlie cognitive deficits in normal aging subjects, but the mechanisms that underlie this change are unknown, possibly due to a paucity of direct measurements from aging neurons. Using CCD and two-photon calcium imaging techniques on CA1 pyramidal neurons from young and aged rats, we show that calcium influx across the plasma membrane increases with aging, and that this change is countered by increased intracellular calcium buff...

  10. Activity-based anorexia during adolescence disrupts normal development of the CA1 pyramidal cells in the ventral hippocampus of female rats.

    Science.gov (United States)

    Chowdhury, Tara G; Ríos, Mariel B; Chan, Thomas E; Cassataro, Daniela S; Barbarich-Marsteller, Nicole C; Aoki, Chiye

    2014-12-01

    Anorexia nervosa (AN) is a psychiatric illness characterized by restricted eating and irrational fears of gaining weight. There is no accepted pharmacological treatment for AN, and AN has the highest mortality rate among psychiatric illnesses. Anorexia nervosa most commonly affects females during adolescence, suggesting an effect of sex and hormones on vulnerability to the disease. Activity-based anorexia (ABA) is a rodent model of AN that shares symptoms with AN, including over-exercise, elevation of stress hormones, and genetic links to anxiety traits. We previously reported that ABA in adolescent female rats results in increased apical dendritic branching in CA1 pyramidal cells of the ventral hippocampus at postnatal day 44 (P44). To examine the long-term effects of adolescent ABA (P44) in female rats, we compared the apical branching in the ventral hippocampal CA1 after recovery from ABA (P51) and after a relapse of ABA (P55) with age-matched controls. To examine the age-dependence of the hippocampal plasticity, we examined the effect of ABA during adulthood (P67). We found that while ABA at P44 resulted in increased branching of ventral hippocampal pyramidal cells, relapse of ABA at P55 resulted in decreased branching. ABA induced during adulthood did not have an effect on dendritic branching, suggesting an age-dependence of the vulnerability to structural plasticity. Cells from control animals were found to exhibit a dramatic increase in branching, more than doubling from P44 to P51, followed by pruning from P51 to P55. The proportion of mature spines on dendrites from the P44-ABA animals is similar to that on dendrites from P55-CON animals. These results suggest that the experience of ABA may cause precocious anatomical development of the ventral hippocampus. Importantly, we found that adolescence is a period of continued development of the hippocampus, and increased vulnerability to mental disorders during adolescence may be due to insults during this

  11. Spatial Gene-Expression Gradients Underlie Prominent Heterogeneity of CA1 Pyramidal Neurons.

    Science.gov (United States)

    Cembrowski, Mark S; Bachman, Julia L; Wang, Lihua; Sugino, Ken; Shields, Brenda C; Spruston, Nelson

    2016-01-20

    Tissue and organ function has been conventionally understood in terms of the interactions among discrete and homogeneous cell types. This approach has proven difficult in neuroscience due to the marked diversity across different neuron classes, but it may be further hampered by prominent within-class variability. Here, we considered a well-defined canonical neuronal population—hippocampal CA1 pyramidal cells (CA1 PCs)—and systematically examined the extent and spatial rules of transcriptional heterogeneity. Using next-generation RNA sequencing, we identified striking variability in CA1 PCs, such that the differences within CA1 along the dorsal-ventral axis rivaled differences across distinct pyramidal neuron classes. This variability emerged from a spectrum of continuous gene-expression gradients, producing a transcriptional profile consistent with a multifarious continuum of cells. This work reveals an unexpected amount of variability within a canonical and narrowly defined neuronal population and suggests that continuous, within-class heterogeneity may be an important feature of neural circuits. PMID:26777276

  12. Suppressive Effects of Resveratrol Treatment on The Intrinsic Evoked Excitability of CA1 Pyramidal Neurons

    Directory of Open Access Journals (Sweden)

    Gholamhossein Meftahi

    2015-10-01

    Full Text Available Objective: Resveratrol, a phytoalexin, has a wide range of desirable biological actions. Despite a growing body of evidence indicating that resveratrol induces changes in neuronal function, little effort, if any, has been made to investigate the cellular effect of resveratrol treatment on intrinsic neuronal properties. Materials and Methods: This experimental study was performed to examine the acute effects of resveratrol (100 μM on the intrinsic evoked responses of rat Cornu Ammonis (CA1 pyramidal neurons in brain slices, using whole cell patch clamp recording under current clamp conditions. Results: Findings showed that resveratrol treatment caused dramatic changes in evoked responses of pyramidal neurons. Its treatment induced a significant (P<0.05 increase in the after hyperpolarization amplitude of the first evoked action potential. Resveratrol-treated cells displayed a significantly broader action potential (AP when compared with either control or vehicle-treated groups. In addition, the mean instantaneous firing frequency between the first two action potentials was significantly lower in resveratrol-treated neurons. It also caused a significant reduction in the time to maximum decay of AP. The rheobase current and the utilization time were both significantly greater following resveratrol treatment. Neurons exhibited a significantly depolarized voltage threshold when exposed to resveratrol. Conclusion: Results provide direct electrophysiological evidence for the inhibitory effects of resveratrol on pyramidal neurons, at least in part, by reducing the evoked neural activity.

  13. Activation of functional α7-containing nAChRs in hippocampal CA1 pyramidal neurons by physiological levels of choline in the presence of PNU-120596.

    Directory of Open Access Journals (Sweden)

    Bopanna I Kalappa

    Full Text Available BACKGROUND: The level of expression of functional α7-containing nicotinic acetylcholine receptors (nAChRs in hippocampal CA1 pyramidal neurons is believed to be very low compared to hippocampal CA1 interneurons, and for many years this expression was largely overlooked. However, high densities of expression of functional α7-containing nAChRs in CA1 pyramidal neurons may not be necessary for triggering important cellular and network functions, especially if activation of α7-containing nAChRs occurs in the presence of positive allosteric modulators such as PNU-120596. METHODOLOGY/PRINCIPAL FINDINGS: An approach previously developed for α7-containing nAChRs expressed in tuberomammillary neurons was applied to investigate functional CA1 pyramidal α7-containing nAChRs using rat coronal hippocampal slices and patch-clamp electrophysiology. The majority (∼71% of tested CA1 pyramidal neurons expressed low densities of functional α7-containing nAChRs as evidenced by small whole-cell responses to choline, a selective endogenous agonist of α7 nAChRs. These responses were potentiated by PNU-120596, a novel positive allosteric modulator of α7 nAChRs. The density of functional α7-containing nAChRs expressed in CA1 pyramidal neurons (and thus, the normalized net effect of activation, i.e., response net charge per unit of membrane capacitance per unit of time was estimated to be ∼5% of the density observed in CA1 interneurons. The results of this study demonstrate that despite low levels of expression of functional pyramidal α7-containing nAChRs, physiological levels of choline (∼10 µM are sufficient to activate these receptors and transiently depolarize and even excite CA1 pyramidal neurons in the presence of PNU-120596. The observed effects are possible because in the presence of 10 µM choline and 1-5 µM PNU-120596, a single opening of an individual pyramidal α7-containing nAChR ion channel appears to transiently depolarize (∼4 mV the

  14. Interaction between the Spatiotemporal Learning Rule (STLR) and Hebb type (HEBB) in single pyramidal cells in the hippocampal CA1 Area

    OpenAIRE

    Tsukada, Minoru; Yamazaki, Yoshiyuki; Kojima, Hiroshi

    2007-01-01

    The spatiotemporal learning rule (STLR), proposed as a non-Hebb type by Tsukada et al. (Neural Networks 9 (1996) 1357 and Tsukada and Pan (Biol. cyberm 92 (2005) 139), 2005), consists of two distinctive factors; “cooperative plasticity without a cell spike,” and “its temporal summation”. On the other hand, Hebb (The organization of behavior. John Wiley, New York, 1949) proposed the idea (HEBB) that synaptic modification is strengthened only if the pre- and post-cell are activated simultaneous...

  15. Computational modeling reveals dendritic origins of GABA(A-mediated excitation in CA1 pyramidal neurons.

    Directory of Open Access Journals (Sweden)

    Naomi Lewin

    Full Text Available GABA is the key inhibitory neurotransmitter in the adult central nervous system, but in some circumstances can lead to a paradoxical excitation that has been causally implicated in diverse pathologies from endocrine stress responses to diseases of excitability including neuropathic pain and temporal lobe epilepsy. We undertook a computational modeling approach to determine plausible ionic mechanisms of GABA(A-dependent excitation in isolated post-synaptic CA1 hippocampal neurons because it may constitute a trigger for pathological synchronous epileptiform discharge. In particular, the interplay intracellular chloride accumulation via the GABA(A receptor and extracellular potassium accumulation via the K/Cl co-transporter KCC2 in promoting GABA(A-mediated excitation is complex. Experimentally it is difficult to determine the ionic mechanisms of depolarizing current since potassium transients are challenging to isolate pharmacologically and much GABA signaling occurs in small, difficult to measure, dendritic compartments. To address this problem and determine plausible ionic mechanisms of GABA(A-mediated excitation, we built a detailed biophysically realistic model of the CA1 pyramidal neuron that includes processes critical for ion homeostasis. Our results suggest that in dendritic compartments, but not in the somatic compartments, chloride buildup is sufficient to cause dramatic depolarization of the GABA(A reversal potential and dominating bicarbonate currents that provide a substantial current source to drive whole-cell depolarization. The model simulations predict that extracellular K(+ transients can augment GABA(A-mediated excitation, but not cause it. Our model also suggests the potential for GABA(A-mediated excitation to promote network synchrony depending on interneuron synapse location - excitatory positive-feedback can occur when interneurons synapse onto distal dendritic compartments, while interneurons projecting to the perisomatic

  16. Effects of lithium chloride on outward potassium currents in acutely isolated hippocampal CA1 pyramidal neurons

    Institute of Scientific and Technical Information of China (English)

    ZHANG Chaofeng; DU Huizhi; YANG Pin

    2006-01-01

    Although lithium possesses neuroprotective functions, the molecular mechanism underlying its actions has not been fully elucidated. In the present paper, the effects of lithium chloride on voltage-dependent potassium currents in the CA1 pyramidal neurons acutely isolated from rat hippocampus were studied using the whole-cell patch-clamp technique. Depolarizing test pulses activated two components of outward potassium currents: a rapidly activating and inactivating component, IA and a delayed component, IK. Results showed that lithium chloride increased the amplitude of IA in a concentration-dependent manner. Half enhancement concentration (EC50) was 22.80±5.45 μmol·L-1. Lithium chloride of 25 μmol·L-1 shifted the steady-state activation curve and inactivation curve of IA to more negative potentials, but mainly affected the activation kinetics. The amplitude and the activation processes of IK were not affected by lithium chloride. The effects of lithium chloride on potassium channel appear to possess neuroprotective properties by Ca2+-lowing effects modulate neuronal excitability by activating IA in rat hippocampal neurons.

  17. THE KINETICS OF MULTIBRANCH INTEGRATION ON THE DENDRITIC ARBOR OF CA1 PYRAMIDAL NEURONS

    Directory of Open Access Journals (Sweden)

    Sunggu eYang

    2014-05-01

    Full Text Available The process by which synaptic inputs separated in time and space are integrated by the dendritic arbor to produce a sequence of action potentials is among the most fundamental signal transformations that takes place within the central nervous system. Some aspects of this complex process, such as integration at the level of individual dendritic branches, have been extensively studied. But other aspects, such as how inputs from multiple branches are combined, and the kinetics of that integration have not been systematically examined. Using a 3D digital holographic photolysis technique to overcome the challenges posed by the complexities of the 3D anatomy of the dendritic arbor of CA1 pyramidal neurons for conventional photolysis, we show that integration on a single dendrite is fundamentally different from that on multiple dendrites. Multibranch integration occurring at oblique and basal dendrites allows somatic action potential firing of the cell to faithfully follow the driving stimuli over a significantly wider frequency range than what is possible with single branch integration. However, multibranch integration requires greater input strength to drive the somatic action potentials. This tradeoff between sensitivity and kinetics may explain the puzzling report of the predominance of multibranch, rather than single branch, integration from in vivo recordings during presentation of visual stimuli.

  18. Altered intrinsic excitability of hippocampal CA1 pyramidal neurons in aged PDAPP mice

    Directory of Open Access Journals (Sweden)

    Francesco Tamagnini

    2015-10-01

    These data show that Aβ-overexpression in aged mice altered the capacitance, the neuronal firing and the AP waveform of CA1 pyramidal neurons. Some of these findings are consistent with previous work on younger PDAPP, they also show important differences that can be potentially ascribed to the interaction between amyloidopathy and ageing. Such a change of IE properties over time underlies that the increased incidence of seizure observed in AD patients might rely on different mechanistic pathways during progression of the disease.

  19. The protective role of ascorbic acid on hippocampal CA1 pyramidal neurons in a rat model of maternal lead exposure.

    Science.gov (United States)

    Sepehri, Hamid; Ganji, Farzaneh

    2016-07-01

    Oxidative stress is a major pathogenic mechanism of lead neurotoxicity. The antioxidant ascorbic acid protects hippocampal pyramidal neurons against cell death during congenital lead exposure; however, critical functions like synaptic transmission, integration, and plasticity depend on preservation of dendritic and somal morphology. This study was designed to examine if ascorbic acid also protects neuronal morphology during developmental lead exposure. Timed pregnant rats were divided into four treatment groups: (1) control, (2) 100mg/kg ascorbic acid once a day via gavage, (3) 0.05% lead acetate in drinking water, and (4) 0.05% lead+100mg/kg oral ascorbic acid. Brains of eight male pups (P25) per treatment group were processed for Golgi staining. Changes in hippocampal CA1 pyramidal neurons' somal size were estimated by cross-sectional area and changes in dendritic arborization by Sholl's analysis. One-way ANOVA was used to compare results among treatment groups. Lead-exposed pups exhibited a significant decrease in somal size compared to controls (Pnear cell body (P<0.05) and a decreased total dendritic length in both apical and basal dendritic trees of CA1 neurons (P<0.05). Ascorbic acid significantly but only partially reversed the somal and dendritic damage caused by developmental lead exposure. Oxidative stress thus contributes to lead neurotoxicity but other pathogenic mechanisms are also involved. PMID:26783884

  20. Endocannabinoids differentially modulate synaptic plasticity in rat hippocampal CA1 pyramidal neurons.

    Directory of Open Access Journals (Sweden)

    Jian-Yi Xu

    Full Text Available BACKGROUND: Hippocampal CA1 pyramidal neurons receive two excitatory glutamatergic synaptic inputs: their most distal dendritic regions in the stratum lacunosum-moleculare (SLM are innervated by the perforant path (PP, originating from layer III of the entorhinal cortex, while their more proximal regions of the apical dendrites in the stratum radiatum (SR are innervated by the Schaffer-collaterals (SC, originating from hippocampal CA3 neurons. Endocannabinoids (eCBs are naturally occurring mediators capable of modulating both GABAergic and glutamatergic synaptic transmission and plasticity via the CB1 receptor. Previous work on eCB modulation of excitatory synapses in the CA1 region largely focuses on the SC pathway. However, little information is available on whether and how eCBs modulate glutamatergic synaptic transmission and plasticity at PP synapses. METHODOLOGY/PRINCIPAL FINDINGS: By employing somatic and dendritic patch-clamp recordings, Ca(2+ uncaging, and immunostaining, we demonstrate that there are significant differences in low-frequency stimulation (LFS- or DHPG-, an agonist of group I metabotropic glutamate receptors (mGluRs, induced long-term depression (LTD of excitatory synaptic transmission between SC and PP synapses in the same pyramidal neurons. These differences are eliminated by pharmacological inhibition with selective CB1 receptor antagonists or genetic deletion of the CB1 receptor, indicating that these differences likely result from differential modulation via a CB1 receptor-dependent mechanism. We also revealed that depolarization-induced suppression of excitation (DSE, a form of short-term synaptic plasticity, and photolysis of caged Ca(2+-induced suppression of Excitatory postsynaptic currents (EPSCs were less at the PP than that at the SC. In addition, application of WIN55212 (WIN induced a more pronounced inhibition of EPSCs at the SC when compared to that at the PP. CONCLUSIONS/SIGNIFICANCE: Our results suggest

  1. PLACE CELL FORMATION BY GRID CELL CONVERGENCE IN THE DENDRITES OF A CA1 MODEL NEURON

    Directory of Open Access Journals (Sweden)

    Evangelia Pollali

    2014-04-01

    Full Text Available Place cells are pyramidal neurons in CA1 and CA3 regions of hippocampus which fire selectively when the animal is located in a particular place in space. CA1 place cells receive synaptic input from CA3 via the Schaffer collateral fibers to their proximal apical and basal dendrites and from the third layer of medial entorhinal cortex to their apical tuft dendrites. Both of these input pathways encode spatial information. Grid cells, which form the entorhinal input to CA1 cells, have a spatial firing field with multiple peaks which displays a regularly spaced, triangular grid pattern that covers the entire space of a given environment. Both grid and place cells are phase-modulated by theta rhythm and this modulation may be important for their spatial properties. Studying the formation of place cells is an important step in understanding how representation of the external environment is coded in neural networks that constitute spatial maps. It is not currently known how place fields emerge in CA1 neurons. An influential model of place cell formation predicts the convergence of various grid field inputs which combine linearly to create the place field output of CA1 cells. In this study, we constructed a model of CA1 place cell formation through the convergence of grid field inputs to the distal dendrites of our model neuron. We created a model of grid cell activity which represents the firing of grid cells modulated be the theta rhythm. We varied the number of different grid fields used as synaptic inputs to stimulate the distal dendrites of a biophysically constrained, detailed compartmental CA1 pyramidal cell model. In addition, inhibition was placed in both the distal and proximal dendrites. These inhibitory pathways are known to be active in different phases of the theta rhythm. We used this model to study the properties of CA1 place cell formation and to assess the output of the CA1 model cell during place cell activity. Additionally, we

  2. Cholinergic-mediated IP3-receptor activation induces long-lasting synaptic enhancement in CA1 pyramidal neurons

    OpenAIRE

    Fernández de Sevilla, D.; Núñez Molina, Ángel; Borde, M.; Malinow, R.; Buño, Washinton

    2008-01-01

    Cholinergic-glutamatergic interactions influence forms of synaptic plasticity that are thought to mediate memory and learning. We tested in vitro the induction of long-lasting synaptic enhancement at Schaffer collaterals by acetylcholine (ACh) at the apical dendrite of CA1 pyramidal neurons and in vivo by stimulation of cholinergic afferents. In vitro ACh induced a Ca2+ wave and synaptic enhancement mediated by insertion of AMPA receptors in spines. Activation of muscarinic ACh receptors (mAC...

  3. Evidence for Alzheimer's disease-linked synapse loss and compensation in mouse and human hippocampal CA1 pyramidal neurons.

    Science.gov (United States)

    Neuman, Krystina M; Molina-Campos, Elizabeth; Musial, Timothy F; Price, Andrea L; Oh, Kwang-Jin; Wolke, Malerie L; Buss, Eric W; Scheff, Stephen W; Mufson, Elliott J; Nicholson, Daniel A

    2015-11-01

    Alzheimer's disease (AD) is associated with alterations in the distribution, number, and size of inputs to hippocampal neurons. Some of these changes are thought to be neurodegenerative, whereas others are conceptualized as compensatory, plasticity-like responses, wherein the remaining inputs reactively innervate vulnerable dendritic regions. Here, we provide evidence that the axospinous synapses of human AD cases and mice harboring AD-linked genetic mutations (the 5XFAD line) exhibit both, in the form of synapse loss and compensatory changes in the synapses that remain. Using array tomography, quantitative conventional electron microscopy, immunogold electron microscopy for AMPARs, and whole-cell patch-clamp physiology, we find that hippocampal CA1 pyramidal neurons in transgenic mice are host to an age-related synapse loss in their distal dendrites, and that the remaining synapses express more AMPA-type glutamate receptors. Moreover, the number of axonal boutons that synapse with multiple spines is significantly reduced in the transgenic mice. Through serial section electron microscopic analyses of human hippocampal tissue, we further show that putative compensatory changes in synapse strength are also detectable in axospinous synapses of proximal and distal dendrites in human AD cases, and that their multiple synapse boutons may be more powerful than those in non-cognitively impaired human cases. Such findings are consistent with the notion that the pathophysiology of AD is a multivariate product of both neurodegenerative and neuroplastic processes, which may produce adaptive and/or maladaptive responses in hippocampal synaptic strength and plasticity. PMID:25031178

  4. Maternal mobile phone exposure alters intrinsic electrophysiological properties of CA1 pyramidal neurons in rat offspring.

    Science.gov (United States)

    Razavinasab, Moazamehosadat; Moazzami, Kasra; Shabani, Mohammad

    2016-06-01

    Some studies have shown that exposure to electromagnetic field (EMF) may result in structural damage to neurons. In this study, we have elucidated the alteration in the hippocampal function of offspring Wistar rats (n = 8 rats in each group) that were chronically exposed to mobile phones during their gestational period by applying behavioral, histological, and electrophysiological tests. Rats in the EMF group were exposed to 900 MHz pulsed-EMF irradiation for 6 h/day. Whole cell recordings in hippocampal pyramidal cells in the mobile phone groups did show a decrease in neuronal excitability. Mobile phone exposure was mostly associated with a decrease in the number of action potentials fired in spontaneous activity and in response to current injection in both male and female groups. There was an increase in the amplitude of the afterhyperpolarization (AHP) in mobile phone rats compared with the control. The results of the passive avoidance and Morris water maze assessment of learning and memory performance showed that phone exposure significantly altered learning acquisition and memory retention in male and female rats compared with the control rats. Light microscopy study of brain sections of the control and mobile phone-exposed rats showed normal morphology.Our results suggest that exposure to mobile phones adversely affects the cognitive performance of both female and male offspring rats using behavioral and electrophysiological techniques. PMID:24604340

  5. Phasic and tonic type A γ-Aminobutryic acid receptor mediated effect of Withania somnifera on mice hippocampal CA1 pyramidal Neurons

    Directory of Open Access Journals (Sweden)

    Janardhan Prasad Bhattarai

    2014-01-01

    Full Text Available Background: In Nepali and Indian system of traditional medicine, Withania somnifera (WS is considered as a rejuvenative medicine to maintain physical and mental health and has also been shown to improve memory consolidation. Objective: In this study, a methanolic extract of WS (mWS was applied on mice hippocampal CA1 neurons to identify the receptors activated by the WS. Materials and Methods: The whole cell patch clamp recordings were performed on CA1 pyramidal neurons from immature mice (7-20 postnatal days. The cells were voltage clamped at -60 mV. Extract of WS root were applied to identify the effect of mWS. Results: The application of mWS (400 ng/μl induced remarkable inward currents (-158.1 ± 28.08 pA, n = 26 on the CA1 pyramidal neurons. These inward currents were not only reproducible but also concentration dependent. mWS-induced inward currents remained persistent in the presence of amino acid receptor blocking cocktail (AARBC containing blockers for the ionotropic glutamate receptors, glycine receptors and voltage-gated Na + channel (Control: -200.3 ± 55.42 pA, AARBC: -151.5 ± 40.58 pA, P > 0.05 suggesting that most of the responses by mWS are postsynaptic events. Interestingly, these inward currents were almost completely blocked by broad GABA A receptor antagonist, bicuculline- 20 μM (BIC (BIC: -1.46 ± 1.4 pA, P < 0.001, but only partially by synaptic GABA A receptor blocker gabazine (1 μM (GBZ: -18.26 ± 4.70 pA, P < 0.01. Conclusion: These results suggest that WS acts on synaptic/extrasynaptic GABA A receptors and may play an important role in the process of memory and neuroprotection via activation of synaptic and extrasynaptic GABA A receptors.

  6. Temporal dynamics of distinct CA1 cell populations during unconscious state induced by ketamine.

    Directory of Open Access Journals (Sweden)

    Hui Kuang

    Full Text Available Ketamine is a widely used dissociative anesthetic which can induce some psychotic-like symptoms and memory deficits in some patients during the post-operative period. To understand its effects on neural population dynamics in the brain, we employed large-scale in vivo ensemble recording techniques to monitor the activity patterns of simultaneously recorded hippocampal CA1 pyramidal cells and various interneurons during several conscious and unconscious states such as awake rest, running, slow wave sleep, and ketamine-induced anesthesia. Our analyses reveal that ketamine induces distinct oscillatory dynamics not only in pyramidal cells but also in at least seven different types of CA1 interneurons including putative basket cells, chandelier cells, bistratified cells, and O-LM cells. These emergent unique oscillatory dynamics may very well reflect the intrinsic temporal relationships within the CA1 circuit. It is conceivable that systematic characterization of network dynamics may eventually lead to better understanding of how ketamine induces unconsciousness and consequently alters the conscious mind.

  7. Local Optogenetic Induction of Fast (20-40 Hz Pyramidal-Interneuron Network Oscillations in the In Vitro and In Vivo CA1 Hippocampus: Modulation by CRF and Enforcement of Perirhinal Theta Activity

    Directory of Open Access Journals (Sweden)

    Julien eDine

    2016-04-01

    Full Text Available The neurophysiological processes that can cause theta-to-gamma frequency range (4-80 Hz network oscillations in the rhinal cortical-hippocampal system and the potential connectivity-based interactions of such forebrain rhythms are a topic of intensive investigation. Here, using selective Channelrhodopsin-2 (ChR2 expression in mouse forebrain glutamatergic cells, we were able to locally, temporally precisely, and reliably induce fast (20-40 Hz field potential oscillations in hippocampal area CA1 in vitro (at 25°C and in vivo (i.e., slightly anaesthetized NEX-Cre-ChR2 mice. As revealed by pharmacological analyses and patch-clamp recordings from pyramidal cells and GABAergic interneurons in vitro, these light-triggered oscillations can exclusively arise from sustained suprathreshold depolarization (~200 ms or longer and feedback inhibition of CA1 pyramidal neurons, as being mandatory for prototypic pyramidal-interneuron network (P-I oscillations. Consistently, the oscillations comprised rhythmically occurring population spikes (generated by pyramidal cells and their frequency increased with increasing spectral power. We further demonstrate that the optogenetically driven CA1 oscillations, which remain stable over repeated evocations, are impaired by the stress hormone corticotropin-releasing factor (CRF, 125 nM in vitro and, even more remarkably, found that they are accompanied by concurrent states of enforced theta activity in the memory-associated perirhinal cortex (PrC in vivo. The latter phenomenon most likely derives from neurotransmission via a known, but poorly studied excitatory CA1PrC pathway. Collectively, our data provide evidence for the existence of a prototypic (CRF-sensitive P-I gamma rhythm generator in area CA1 and suggest that CA1 P-I oscillations can rapidly up-regulate theta activity strength in hippocampus-innervated rhinal networks, at least in the PrC.

  8. Local Optogenetic Induction of Fast (20-40 Hz) Pyramidal-Interneuron Network Oscillations in the In Vitro and In Vivo CA1 Hippocampus: Modulation by CRF and Enforcement of Perirhinal Theta Activity.

    Science.gov (United States)

    Dine, Julien; Genewsky, Andreas; Hladky, Florian; Wotjak, Carsten T; Deussing, Jan M; Zieglgänsberger, Walter; Chen, Alon; Eder, Matthias

    2016-01-01

    The neurophysiological processes that can cause theta-to-gamma frequency range (4-80 Hz) network oscillations in the rhinal cortical-hippocampal system and the potential connectivity-based interactions of such forebrain rhythms are a topic of intensive investigation. Here, using selective Channelrhodopsin-2 (ChR2) expression in mouse forebrain glutamatergic cells, we were able to locally, temporally precisely, and reliably induce fast (20-40 Hz) field potential oscillations in hippocampal area CA1 in vitro (at 25°C) and in vivo (i.e., slightly anesthetized NEX-Cre-ChR2 mice). As revealed by pharmacological analyses and patch-clamp recordings from pyramidal cells and GABAergic interneurons in vitro, these light-triggered oscillations can exclusively arise from sustained suprathreshold depolarization (~200 ms or longer) and feedback inhibition of CA1 pyramidal neurons, as being mandatory for prototypic pyramidal-interneuron network (P-I) oscillations. Consistently, the oscillations comprised rhythmically occurring population spikes (generated by pyramidal cells) and their frequency increased with increasing spectral power. We further demonstrate that the optogenetically driven CA1 oscillations, which remain stable over repeated evocations, are impaired by the stress hormone corticotropin-releasing factor (CRF, 125 nM) in vitro and, even more remarkably, found that they are accompanied by concurrent states of enforced theta activity in the memory-associated perirhinal cortex (PrC) in vivo. The latter phenomenon most likely derives from neurotransmission via a known, but poorly studied excitatory CA1→PrC pathway. Collectively, our data provide evidence for the existence of a prototypic (CRF-sensitive) P-I gamma rhythm generator in area CA1 and suggest that CA1 P-I oscillations can rapidly up-regulate theta activity strength in hippocampus-innervated rhinal networks, at least in the PrC. PMID:27199662

  9. Evidence for neuroprotective effect of sulbutiamine against oxygen-glucose deprivation in rat hippocampal CA1 pyramidal neurons.

    Science.gov (United States)

    Kwag, Jeehyun; Majid, Aman Shah Abdul; Kang, Kui Dong

    2011-01-01

    Hippocampus is one of the earliest brain regions that gets affected by ischemia, however, no pharmacological therapy exists yet that can fully counteract the ischemic damage. Here we study the effect of sulbutiamine, a synthetic thiamine analogue that can cross the blood-brain barrier easily, on hippocampal neurons under an in vitro model of ischemia, oxygen-glucose deprivation (OGD). We find that exposure to OGD in the presence of sulbutiamine significantly increases neuronal viability and enhances electrophysiological properties such as excitatory synaptic transmissions and intrinsic neuronal membrane input resistance in a concentration-dependent manner. Overall, here we report, for the first time, the neuroprotective evidence of sulbutiamine on hippocampal CA1 pyramidal neurons under OGD, which may have beneficial implications as a possible therapeutic agent/substance against ischemic insult. PMID:22040892

  10. Pyramidal Cell-Interneuron Interactions Underlie Hippocampal Ripple Oscillations

    Science.gov (United States)

    Stark, Eran; Roux, Lisa; Eichler, Ronny; Senzai, Yuta; Royer, Sebastien; Buzsáki, György

    2015-01-01

    SUMMARY High-frequency ripple oscillations, observed most prominently in the hippocampal CA1 pyramidal layer, are associated with memory consolidation. The cellular and network mechanisms underlying the generation, frequency control, and spatial coherence of the rhythm are poorly understood. Using multisite optogenetic manipulations in freely behaving rodents, we found that depolarization of a small group of nearby pyramidal cells was sufficient to induce high-frequency oscillations, whereas closed-loop silencing of pyramidal cells or activation of parvalbumin-(PV) or somatostatin-immunoreactive interneurons aborted spontaneously occurring ripples. Focal pharmacological blockade of GABAA receptors abolished ripples. Localized PV inter-neuron activation paced ensemble spiking, and simultaneous induction of high-frequency oscillations at multiple locations resulted in a temporally coherent pattern mediated by phase-locked inter-neuron spiking. These results constrain competing models of ripple generation and indicate that temporally precise local interactions between excitatory and inhibitory neurons support ripple generation in the intact hippocampus. PMID:25033186

  11. Bursting response to current-evoked depolarization in rat CA1 pyramidal neurons is correlated with lucifer yellow dye coupling but not with the presence of calbindin-D28k

    International Nuclear Information System (INIS)

    Calbindin-D28k (CaBP) immunohistochemistry has been combined with electrophysiological recording and Lucifer Yellow (LY) cell identification in the CA1 region of the rat hippocampal formation. CaBP is shown to be contained within a distinct sub-population of CA1 pyramidal cells which is equivalent to the superficial layer described by Lorente de No (1934). The neurogenesis of these CaBP-positive neurons occurs 1-2 days later than the CaBP-negative neurons in the deep pyramidal cell layer, as shown by 3H-thymidine autoradiography. No correlation could be found between the presence or absence of CaBP and the type of electrophysiological response to current-evoked depolarizing pulses. The latter could be separated into bursting or non-bursting types, and the bursting-type response was nearly always found to be associated with the presence of LY dye coupling. Furthermore, when dye coupling involved three neurons, a characteristic pattern was observed which may represent the coupling of phenotypically identical neurons into distinct functional units within the CA1 pyramidal cell layer. In this particular case the three neurons were all likely to be CaBP-positive

  12. Bursting response to current-evoked depolarization in rat CA1 pyramidal neurons is correlated with lucifer yellow dye coupling but not with the presence of calbindin-D28k

    Energy Technology Data Exchange (ETDEWEB)

    Baimbridge, K.G.; Peet, M.J.; McLennan, H.; Church, J. (Department of Physiology, University of British Columbia, Vancouver (Canada))

    1991-04-01

    Calbindin-D28k (CaBP) immunohistochemistry has been combined with electrophysiological recording and Lucifer Yellow (LY) cell identification in the CA1 region of the rat hippocampal formation. CaBP is shown to be contained within a distinct sub-population of CA1 pyramidal cells which is equivalent to the superficial layer described by Lorente de No (1934). The neurogenesis of these CaBP-positive neurons occurs 1-2 days later than the CaBP-negative neurons in the deep pyramidal cell layer, as shown by 3H-thymidine autoradiography. No correlation could be found between the presence or absence of CaBP and the type of electrophysiological response to current-evoked depolarizing pulses. The latter could be separated into bursting or non-bursting types, and the bursting-type response was nearly always found to be associated with the presence of LY dye coupling. Furthermore, when dye coupling involved three neurons, a characteristic pattern was observed which may represent the coupling of phenotypically identical neurons into distinct functional units within the CA1 pyramidal cell layer. In this particular case the three neurons were all likely to be CaBP-positive.

  13. 小鼠海马CA1区锥体神经元树突棘的发育%Dendritic spine development of mouse hippocampal CA1 pyramidal neurons

    Institute of Scientific and Technical Information of China (English)

    刘畅; 范文娟; 程维杰; 左曙光; 邓锦波

    2012-01-01

    Objective To investigate the developmental characteristics of dendritic spines in mouse hippocampal CA1 pyramidal neurons by analysing the spine density and morphological changes. Methods Fifty mice were collected at postnatal days ( P ) 0, 5, 10, 20 and 30, 10 mice for each age. Dil diolistic labeling with gene gun was performed to observe dendritic spines development in mouse hippocampal CA1 pyramidal neurons. High quality labeled neurons were examined and photographed under a confocal microscope, whereas the ultrastructure of spines was observed under a transmission electron microscope. Results Dendritic spines changed their morphology and density with mouse development in response to neuronal activity. The smooth endoplasmic reticulum and spine apparatus in dendritic spines of hippocampal CA1 were observed with electron microscopy analysis, which might be involved in the regulation of plasticity at individual synapses. Conclusion The development of dendritic spines may be closely related to synaptogenesis and the formation of synaptic plasticity.%目的 对小鼠海马CA1区锥体神经元正常发育中树突棘密度及各种形态变化进行分析测定,为深入研究突触发生及突触可塑性提供直接的形态学依据.方法 分别取出生后0、5、10、20及30d 5个年龄段的C57BL/6小鼠各10只,采用基因枪对小鼠海马CA1区锥体神经元树突棘进行亲脂性荧光染料DiI标记,通过激光共焦显微镜对其进行观察分析;同时利用透射电镜技术对树突棘的超微结构进行分析.结果 树突棘的形态、大小及其密度随小鼠发育而变化,成熟树突棘内部存在滑面内质网与棘器,可能参与了突触后膜结合蛋白及其转运体的合成.结论 树突棘的发育过程与突触连接的形成以及突触可塑性密切相关.

  14. Association of Rgs7/Gβ5 complexes with Girk channels and GABAB receptors in hippocampal CA1 pyramidal neurons.

    Science.gov (United States)

    Fajardo-Serrano, Ana; Wydeven, Nicole; Young, Daniele; Watanabe, Masahiko; Shigemoto, Ryuichi; Martemyanov, Kirill A; Wickman, Kevin; Luján, Rafael

    2013-12-01

    In the hippocampus, signaling through G protein-coupled receptors is modulated by Regulators of G protein signaling (Rgs) proteins, which act to stimulate the rate of GTP hydrolysis, and consequently, G protein inactivation. The R7-Rgs subfamily selectively deactivates the G(i/o)-class of Gα subunits that mediate the action of several GPCRs. Here, we used co-immunoprecipitation, electrophysiology and immunoelectron microscopy techniques to investigate the formation of macromolecular complexes and spatial relationship of Rgs7/Gβ5 complexes and its prototypical signaling partners, the GABAB receptor and Girk channel. Co-expression of recombinant GABAB receptors and Girk channels in combination with co-immunoprecipitation experiments established that the Rgs7/Gβ5 forms complexes with GABAB receptors or Girk channels. Using electrophysiological experiments, we found that GABAB -Girk current deactivation kinetics was markedly faster in cells coexpressing Rgs7/Gβ5. At the electron microscopic level, immunolabeling for Rgs7 and Gβ5 proteins was found primarily in the dendritic layers of the hippocampus and showed similar distribution patterns. Immunoreactivity was mostly localized along the extrasynaptic plasma membrane of dendritic shafts and spines of pyramidal cells and, to a lesser extent, to that of presynaptic terminals. Quantitative analysis of immunogold particles for Rgs7 and Gβ5 revealed an enrichment of the two proteins around excitatory synapses on dendritic spines, virtually identical to that of Girk2 and GABAB1 . These data support the existence of macromolecular complexes composed of GABAB receptor-G protein-Rgs7-Girk channels in which Rgs7 and Gβ5 proteins may preferentialy modulate GABAB receptor signaling through the deactivation of Girk channels on dendritic spines. In contrast, Rgs7 and Girk2 were associated but mainly segregated from GABAB1 in dendritic shafts, where Rgs7/Gβ5 signaling complexes might modulate Girk-dependent signaling via a

  15. Latent N-methyl-D-aspartate receptors in the recurrent excitatory pathway between hippocampal CA1 pyramidal neurons: Ca(2+)-dependent activation by blocking A1 adenosine receptors.

    OpenAIRE

    Klishin, A; Tsintsadze, T.; Lozovaya, N.; Krishtal, O

    1995-01-01

    When performed at increased external [Ca2+]/[Mg2+] ratio (2.5 mM/0.5 mM), temporary block of A1 adenosine receptors in hippocampus [by 8-cyclopentyltheophylline (CPT)] leads to a dramatic and irreversible change in the excitatory postsynaptic current (EPSC) evoked by Schaffer collateral/commissural (SCC) stimulation and recorded by in situ patch clamp in CA1 pyramidal neurons. The duration of the EPSC becomes stimulus dependent, increasing with increase in stimulus strength. The later occurri...

  16. Effects of FK506 on Hippocampal CA1 Cells Following Transient Global Ischemia/Reperfusion in Wistar Rat

    Directory of Open Access Journals (Sweden)

    Zahra-Nadia Sharifi

    2012-01-01

    Full Text Available Transient global cerebral ischemia causes loss of pyramidal cells in CA1 region of hippocampus. In this study, we investigated the neurotrophic effect of the immunosuppressant agent FK506 in rat after global cerebral ischemia. Both common carotid arteries were occluded for 20 minutes followed by reperfusion. In experimental group 1, FK506 (6 mg/kg was given as a single dose exactly at the time of reperfusion. In the second group, FK506 was administered at the beginning of reperfusion, followed by its administration intraperitoneally (IP 6, 24, 48, and 72 hours after reperfusion. FK506 failed to show neurotrophic effects on CA1 region when applied as a single dose of 6 mg/kg. The cell number and size of the CA1 pyramidal cells were increased, also the number of cell death decreased in this region when FK506 was administrated 48 h after reperfusion. This work supports the possible use of FK506 in treatment of ischemic brain damage.

  17. Dopamine modulates Spike Timing-Dependent Plasticity and action potential properties in CA1 pyramidal neurons of acute rat hippocampal slices

    Directory of Open Access Journals (Sweden)

    Elke eEdelmann

    2011-11-01

    Full Text Available Spike Timing-Dependent Plasticity (STDP is a cellular model of hebbian synaptic plasticity which is believed to underlie memory formation. In an attempt to establish a STDP paradigm in CA1 of acute hippocampal slices from juvenile rats (P15-20, we found that changes in excitability resulting from different slice preparation protocols correlate with the success of STDP induction. Slice preparation with sucrose containing ACSF prolonged rise time, reduced frequency adaptation, and decreased latency of action potentials in CA1 pyramidal neurons compared to preparation in conventional ASCF, while other basal electrophysiological parameters remained unaffected. Whereas we observed prominent timing-dependent (t-LTP to 171 ± 10% of controls in conventional ACSF, STDP was absent in sucrose prepared slices. This sucrose-induced STDP deficit could not be rescued by stronger STDP paradigms, applying either more pre- and/or postsynaptic stimuli, or by a higher stimulation frequency. Importantly, slice preparation with sucrose containing ACSF did not eliminate theta-burst stimulation induced LTP in CA1 in field potential recordings in our rat hippocampal slices. Application of dopamine (for 10-20 min to sucrose prepared slices completely rescued t-LTP and recovered action potential properties back to levels observed in ACSF prepared slices. Conversely, acute inhibition of D1 receptor signaling impaired t-LTP in ACSF prepared slices. No similar restoring effect for STDP as seen with dopamine was observed in response to the β-adrenergic agonist isoproterenol. ELISA measurements demonstrated a significant reduction of endogenous dopamine levels (to 61.9 ± 6.9% of ACSF values in sucrose prepared slices. These results lead us to suggest that dopamine dependent regulation of action potential properties correlates with the efficiency to elicit STDP in CA1 pyramidal neurons.

  18. Fast gamma oscillations are generated intrinsically in CA1 without the involvement of fast-spiking basket cells.

    Science.gov (United States)

    Craig, Michael T; McBain, Chris J

    2015-02-25

    Information processing in neuronal networks relies on the precise synchronization of ensembles of neurons, coordinated by the diverse family of inhibitory interneurons. Cortical interneurons can be usefully parsed by embryonic origin, with the vast majority arising from either the caudal or medial ganglionic eminences (CGE and MGE). Here, we examine the activity of hippocampal interneurons during gamma oscillations in mouse CA1, using an in vitro model where brief epochs of rhythmic activity were evoked by local application of kainate. We found that this CA1 KA-evoked gamma oscillation was faster than that in CA3 and, crucially, did not appear to require the involvement of fast-spiking basket cells. In contrast to CA3, we also found that optogenetic inhibition of pyramidal cells in CA1 did not significantly affect the power of the oscillation, suggesting that excitation may not be essential for gamma genesis in this region. We found that MGE-derived interneurons were generally more active than CGE interneurons during CA1 gamma, although a group of CGE-derived interneurons, putative trilaminar cells, were strongly phase-locked with gamma oscillations and, together with MGE-derived axo-axonic and bistratified cells, provide attractive candidates for being the driver of this locally generated, predominantly interneuron-driven model of gamma oscillations. PMID:25716860

  19. Huperzine A enhances excitatory synaptic transmission in CA1 pyramidal neurons of adult rat hippocampal slices%石杉碱甲增强大鼠海马脑片CA1锥体神经元的兴奋性突触传递

    Institute of Scientific and Technical Information of China (English)

    吴小未; 王邦安; 汪萌芽

    2012-01-01

    AIM: To observe the effects of huperzine A (Hup-A) on excitatory synaptic transmission in CA1 pyramidal neurons of adult rat hippocampal slices and to gain an insight into the cellular electrophysiological mechanisms underlying the potentiation of learning and memory by Hup-A. METHODS: The intracellular recordings from CA1 pyramidal neurons in hippocampal slices related to learning and memory were made to analyze mechanisms of Hup-A actions on cell electrophysiological properties and excitatory postsynaptic potential (EPSP) evoked by stimulating Schaffer collaterals. RESULTS; (1) During bath of Hup-A (1 μmol/L), the changes of cell electrophysiological properties were not significant (P>0. 05). (2) Superfu-sion of Hup-A (0. 3 - 3. 0 μmol/L, 15 min) in- creased amplitude, duration and area under curve of EPSPs, which was concentration-dependent, recoverable, but sensitive to atropine pretreatment (10 μmol/L, n = 4). (3) Hup-A did not result in remarkable changes of depolarizing response induced by exogenous glutamate (n=5). CONCLUSION, By the facilitation of the synaptic transmissions, Hup-A may potentiate the activities of hippocampal CA1 pyramidal neurons, and its actions on EPSP is related to the excitation of muscarinic type of acetylcholin-ergic receptors.%目的:观察石杉碱甲(Hup-A)对海马CA1锥体神经元兴奋性突触传递的影响,以探讨其增强学习记忆功能的神经细胞电生理机制.方法:应用大鼠海马脑片CA1锥体神经元细胞内记录技术,观察Hup-A对大鼠海马CA1锥体神经元膜电性质和刺激Schaffer侧支诱发的兴奋性突触后电位( EPSP)的影响.结果:(1) Hup-A(1 μmol/L)灌流15 min对CA1锥体神经元的膜电性质没有显著性影响.(2) Hup-A (0.3~3.0 μmol/L)浓度依赖性使EPSP幅度升高、时程延长、曲线下面积增大,该作用可被阿托品(10μmol/L)预处理取消.(3)Hup-A对外源性谷氨酸诱导的去极化反应无明显影响.结论:Hup-A可增强CA1

  20. Memory-enhancing intra-basolateral amygdala clenbuterol infusion reduces post-burst afterhyperpolarizations in hippocampal CA1 pyramidal neurons following inhibitory avoidance learning.

    Science.gov (United States)

    Lovitz, E S; Thompson, L T

    2015-03-01

    Activation of the basolateral amygdala can modulate the strength of fear memories, including those in single-trial inhibitory avoidance (IA) tasks. Memory retention, measured by the latency to re-enter a dark-compartment paired 24h earlier with a footshock, varies with intensity of this aversive stimulus. When higher intensity footshocks were used, hippocampal CA1 pyramidal neurons exhibited reduced afterhyperpolarizations (AHPs) 24h post-trial, an effect blocked by immediate post-trial inactivation of the basolateral complex of the amygdala (BLA). Similar AHP reductions in CA1 have been observed in a number of learning tasks, with time courses appropriate to support memory consolidation. When less intense footshocks were used for IA training of Sprague-Dawley rats, immediate post-trial infusion of the β-adrenergic agonist clenbuterol into BLA was required to enhance hippocampal Arc protein expression 45 min later and to enhance memory retention tested 48 h later. Here, using Long-Evans rats and low-intensity footshocks, we confirmed that bilateral immediate post-trial infusion of 15 ng/0.5 μl of the β-adrenergic agonist clenbuterol into BLA significantly enhances memory for an IA task. Next, clenbuterol was infused into one BLA immediately post-training, with vehicle infused into the contralateral BLA, then hippocampal CA1 neuron AHPs were assessed 24 h later. Only CA1 neurons from hemispheres ipsilateral to post-trial clenbuterol infusion showed learning-dependent AHP reductions. Excitability of CA1 neurons from the same trained rats, but from the vehicle-infused hemispheres, was identical to that from untrained rats receiving unilateral clenbuterol or vehicle infusions. Peak AHPs, medium and slow AHPs, and accommodation were reduced only with the combination of IA training and unilateral BLA β-receptor activation. Similar to previous observations of BLA adrenergic memory-related enhancement of Arc protein expression in hippocampus, increased CA1 neuronal

  1. Sub-millisecond firing synchrony of closely neighboring pyramidal neurons in hippocampal CA1 of rats during delayed non-matching to sample task

    Directory of Open Access Journals (Sweden)

    Susumu Takahashi

    2009-09-01

    Full Text Available Firing synchrony among neurons is thought to play functional roles in several brain regions. In theoretical analyses, firing synchrony among neurons within sub-millisecond precision is feasible to convey information. However, little is known about the occurrence and the functional significance of the sub-millisecond synchrony among closely neighboring neurons in the brain of behaving animals because of a technical issue: spikes simultaneously generated from closely neighboring neurons are overlapped in the extracellular space and are not easily separated. As described herein, using a unique spike sorting technique based on independent component analysis together with extracellular 12-channel multi-electrodes (dodecatrodes, we separated such overlapping spikes and investigated the firing synchrony among closely neighboring pyramidal neurons in the hippocampal CA1 of rats during a delayed non-matching to sample task. Results showed that closely neighboring pyramidal neurons in the hippocampal CA1 can co-fire with sub-millisecond precision. The synchrony generally co-occurred with the firing rate modulation in relation to both internal (retention and comparison and external (stimulus input and motor output events during the task. However, the synchrony occasionally occurred in relation to stimulus inputs even when rate modulation was clearly absent, suggesting that the synchrony is not simply accompanied with firing rate modulation and that the synchrony and the rate modulation might code similar information independently. We therefore conclude that the sub-millisecond firing synchrony in the hippocampus is an effective carrier for propagating information—as represented by the firing rate modulations—to downstream neurons.

  2. Activation of CRH receptor type 1 expressed on glutamatergic neurons increases excitability of CA1 pyramidal neurons by the modulation of voltage-gated ion channels

    Directory of Open Access Journals (Sweden)

    Stephan eKratzer

    2013-07-01

    Full Text Available Corticotropin-releasing hormone (CRH plays an important role in a substantial number of patients with stress-related mental disorders, such as anxiety disorders and depression. CRH has been shown to increase neuronal excitability in the hippocampus, but the underlying mechanisms are poorly understood. The effects of CRH on neuronal excitability were investigated in acute hippocampal brain slices. Population spikes (PS and field excitatory postsynaptic potentials (fEPSP were evoked by stimulating Schaffer-collaterals and recorded simultaneously from the somatic and dendritic region of CA1 pyramidal neurons. CRH was found to increase PS amplitudes (mean  Standard error of the mean; 231.8  31.2% of control; n=10 while neither affecting fEPSPs (104.3 ± 4.2%; n=10 nor long-term potentiation (LTP. However, when Schaffer-collaterals were excited via action potentials (APs generated by stimulation of CA3 pyramidal neurons, CRH increased fEPSP amplitudes (119.8 ± 3.6%; n=8 and the magnitude of LTP in the CA1 region. Experiments in slices from transgenic mice revealed that the effect on PS amplitude is mediated exclusively by CRH receptor 1 (CRHR1 expressed on glutamatergic neurons. The effects of CRH on PS were dependent on phosphatase-2B, L- and T-type calcium channels and voltage-gated potassium channels but independent on intracellular Ca2+-elevation. In patch-clamp experiments, CRH increased the frequency and decay times of APs and decreased currents through A-type and delayed-rectifier potassium channels. These results suggest that CRH does not affect synaptic transmission per se, but modulates voltage-gated ion currents important for the generation of APs and hence elevates by this route overall neuronal activity.

  3. Kynurenic acid inhibits glutamatergic transmission to CA1 pyramidal neurons via α7 nAChR-dependent and -independent mechanisms.

    Science.gov (United States)

    Banerjee, Jyotirmoy; Alkondon, Manickavasagom; Albuquerque, Edson X

    2012-10-15

    Glutamatergic hypofunction and elevated levels of kynurenic acid (KYNA) in the brain are common features of patients with schizophrenia. In vivo studies indicate that in the hippocampus KYNA decreases glutamate levels, presumably via inhibition of α7 nicotinic receptors (nAChRs). Here we tested the hypothesis that basal synaptic glutamate activity in the hippocampus is regulated by tonically active α7 nAChRs and is sensitive to inhibition by KYNA. To this end, spontaneous excitatory postsynaptic currents (EPSCs), sensitive to AMPA receptor antagonist CNQX (10 μM), were recorded from CA1 pyramidal neurons at -70 mV in rat hippocampal slices. The α7 nAChR antagonists α-bungarotoxin (α-BGT, 100 nM) and methyllycaconitine (MLA, 1-50 nM), and the NMDA receptor antagonist 2-amino-5-phosphonovaleric acid (APV, 50 μM) reduced the frequency of EPSCs. MLA and α-BGT had no effect on miniature EPSCs (mEPSCs). The effect of MLA decreased in the presence of APV (50 μM), with 1 nM MLA becoming completely ineffective. KYNA (1-20 μM) suppressed the frequency of EPSCs, without affecting mEPSCs. The effect of KYNA decreased in the presence of MLA (1 nM) or α-BGT (100 nM), with 1 μM KYNA being devoid of any effect. In the presence of both MLA (10 nM) and APV (50 μM) higher KYNA concentrations (5-20 μM) still reduced the frequency of EPSCs. These results suggest that basal synaptic glutamate activity in CA1 pyramidal neurons is maintained in part by tonically active α7 nAChRs and NMDA receptors and is inhibited by micromolar concentrations of KYNA, acting via α7 nAChR-dependent and -independent mechanisms. PMID:22889930

  4. Enhanced sensitivity to ethanol-induced inhibition of LTP in CA1 pyramidal neurons of socially isolated C57BL/6J mice: role of neurosteroids

    Directory of Open Access Journals (Sweden)

    Giuseppe eTalani

    2011-10-01

    Full Text Available Ethanol (EtOH–induced impairment of long-term potentiation (LTP in the rat hippocampus is prevented by the 5α-reductase inhibitor finasteride, suggesting that this effect of EtOH is dependent on the increased local release of neurosteroids such as 3α,5α-THP that promote GABA–mediated transmission. Given that social isolation (SI in rodents is associated with altered plasma and brain levels of such neurosteroids as well as with an enhanced neurosteroidogenic action of EtOH, we examined whether the inhibitory effect of EtOH on LTP at CA3-CA1 hippocampal excitatory synapses is altered in C57BL/6J mice subjected to SI for 6 weeks in comparison with group-housed (GH animals. Extracellular recording of fEPSPs as well as patch-clamp analysis were performed in hippocampal slices prepared from both SI and GH mice. Consistent with previous observations, recording of fEPSPs revealed that the extent of LTP induced in the CA1 region of SI mice was significantly reduced compared with that in GH animals. EtOH (40 mM inhibited LTP in slices from SI mice but not in those from GH mice, and this effect of EtOH was abolished by co-application of 1 µM finasteride. Current-clamp analysis of CA1 pyramidal neurons revealed a decrease in action potential frequency and an increase in the intensity of injected current required to evoke the first action potential in SI mice compared with GH mice, indicative of a decrease in neuronal excitability associated with SI. Together, our data suggest that SI results in reduced levels of neuronal excitability and synaptic plasticity in the hippocampus. Furthermore, the increased sensitivity to the neurosteroidogenic effect of EtOH associated with SI likely accounts for the greater inhibitory effect of EtOH on LTP in SI mice. The increase in EtOH sensitivity induced by SI may be important for the changes in the effects of EtOH on anxiety and on learning and memory associated with the prolonged stress attributable to social

  5. Changes of delayed neuronal death of pyramidal cell and mitochondria by transmission electron microscopy in rats' hippocampus after endurance training and exhaustion treadmill running%耐力训练及力竭运动后大鼠大脑CA1区锥体细胞迟发性神经元死亡及其线粒体的超微结构变化

    Institute of Scientific and Technical Information of China (English)

    张雁儒; 张建军; 冯富明; 李月白; 王义生

    2012-01-01

    目的 观察耐力训练及力竭运动后大鼠大脑海马区锥体细胞及其线粒体的超微结构变化.方法 实验于2007年6月至2008年11月在郑州大学完成.选取8周龄雄性SD大鼠40只,随机设耐力训练组:安静组;急性力竭运动后24 h组;耐力训练+急性力竭运动后即刻组;耐力训练+急性力竭运动后24h组.每组10只.安静组不外加运动,其他组次日进行力竭运动,力竭运动开始的速度为10 m/min,逐渐提高速度并在3 min内到达预定的速度(中等强度、大强度力竭运动的速度分别为20 m/min、36 m/min),保持速度直至力竭,并记录力竭运动时间.耐力训练方案:大鼠在动物跑台进行运动训练,1次/d,6d/周.跑台速度由开始的10 m/min逐渐增加至第4周30 m/min,运动时间由30 min/d增加到40 min/d.力竭标准为大鼠用毛刷驱赶无效,在跑台尾端停留2 s仍不愿跑,且失去快速翻正反射.主要观察指标:断头处死分别取材检测大鼠大脑海马区锥体细胞及其线粒体的超微结构变化.结果 40只SD大鼠均完成实验设计方案,全部进入结果分析.结果发现耐力训练和力竭运动后大鼠大脑细胞凋亡数量显著增加,力竭运动强度增加,凋亡细胞数量增多,且多为神经胶质细胞,安静组大脑细胞凋亡率为(6.56±1.24)%、急性运动后24h组为(16.14 ±3.26)%、耐力训练+急性运动后即刻组为(29.78±1.96)%、耐力训练+急性运动后24h组为(32.43±2.35)%.通过图像分析系统的分析研究,海马神经元线粒体变性较为显著.结论 本实验观察到耐力训练和力竭运动对大脑细胞造成一定的损伤,海马区神经元线粒体变性,可能是由于疲劳训练引起脑组织的酸中毒和缺氧引起大脑细胞的一些变性现象.%Objective The pyramid neurons in the CA1 subfield of the hippocampus are vulnerable to ischemic attack,and transient global ischemia can lead to a specific neuronal death called the

  6. Network models provide insights into how oriens–lacunosum-moleculare and bistratified cell interactions influence the power of local hippocampal CA1 theta oscillations

    Directory of Open Access Journals (Sweden)

    Katie A Ferguson

    2015-08-01

    Full Text Available Hippocampal theta is a 4-12 Hz rhythm associated with episodic memory, and although it has been studied extensively, the cellular mechanisms underlying its generation are unclear. The complex interactions between different interneuron types, such as those between oriens--lacunosum-moleculare (OLM interneurons and bistratified cells (BiCs, make their contribution to network rhythms difficult to determine experimentally. We created network models that are tied to experimental work at both cellular and network levels to explore how these interneuron interactions affect the power of local oscillations. Our cellular models were constrained with properties from patch clamp recordings in the CA1 region of an intact hippocampus preparation in vitro. Our network models are composed of three different types of interneurons: parvalbumin-positive (PV+ basket and axo-axonic cells (BC/AACs, PV+ BiCs, and somatostatin-positive OLM cells. Also included is a spatially extended pyramidal cell model to allow for a simplified local field potential representation, as well as experimentally-constrained, theta frequency synaptic inputs to the interneurons. The network size, connectivity, and synaptic properties were constrained with experimental data. To determine how the interactions between OLM cells and BiCs could affect local theta power, we explored a number of OLM-BiC connections and connection strengths.We found that our models operate in regimes in which OLM cells minimally or strongly affected the power of network theta oscillations due to balances that, respectively, allow compensatory effects or not. Inactivation of OLM cells could result in no change or even an increase in theta power. We predict that the dis-inhibitory effect of OLM cells to BiCs to pyramidal cell interactions plays a critical role in the power of network theta oscillations. Our network models reveal a dynamic interplay between different classes of interneurons in influencing local theta

  7. Extended studies on the effect of glutamate antagonists on ischemic CA-1 damage

    DEFF Research Database (Denmark)

    Diemer, Nils Henrik; Balchen, T; Bruhn, T;

    1996-01-01

    Glutamate receptors are numerous on the ischemia vulnerable CA-1 pyramidal cells. Postischemic use of the AMPA antagonist NBQX has shown up to 80% protection against cell death. Three aspects of this were studied: In the first study, male Wistar rats were given NBQX (30 mg/kg x 3) either 20 hours...... protection. In the third study referred here, two groups of ischemic rats were given NBQX (30 mg/kg x 3) immediately after ischemia. The groups survive for six and 21 days, respectively. Counting of CA-1 pyramidal cells showed an equal, significant protection in both groups (approx 20% cell loss)....

  8. 钾通道阻断剂4-氨基吡啶诱导海马CA1锥体神经元钙瞬变%Calcium transient of CA1 pyramidal neurons induced by potassium blocker 4-aminopyridine in acute hippocampal slices

    Institute of Scientific and Technical Information of China (English)

    苏涛; 丛文东; 廖卫平

    2011-01-01

    Objective To investigate the calcium transient of CA1 pyramidal neurons induced by potassium blocker 4-aminopyridine (4-AP) in acute hippocampal slices to explore the relation between potassium channel function and calcium transient, and their mechanism. Methods Fluorescent probe was employed to mark the hippocampai neurons in acute brain slices of rats; confocal microscopy was used to perform calcium imaging to observe the influences of different concentrations of 4-AP and perfusate with/without calcium on calcium transient of CA1 pyramidal neurons. Results The response of [Ca2+]I to lower concentration of 4-AP (<15 mmol/L) was in a dose-dependent manner (r2=0.910, P=0.000); the higher the concentration of 4-AP (20-80 mmol/L), the lower the peak level of calcium transient. The latency and amplitude of calcium transient induced by 4-AP were obviously reduced when the extracellular condition was switched to an absence of calcium, which was significantly different as compared with that with calcium (P<0.05). Conclusion Blockade of potassium channels with 4-AP can increase [Ca2+]I in the hippocampal pyramidal neurons of acute slices. The increase of [Ca2+]1 to 4-AP could be ascribe to calcium release from intracellular stores and calcium influx from extracellular matrix.%目的 研究4-氨基吡啶(4-AP)诱导的急性脑片海马CA1锥体神经元钙瞬变现象,探讨钾通道功能与钙瞬变的关系及可能机制.方法 荧光探针标记正常大鼠急性脑片海马神经元.共聚焦显微镜技术进行钙成像,观察不同浓度4-AP及细胞灌流液条件对神经元钙瞬变的影响.结果 低浓度(<15 mmol/L)4-AP诱导的钙瞬变峰值与剂量呈线性相关(r2=0.910,P=0.000),高浓度(20~80 mmol/L)4-AP诱导的钙瞬变峰值随浓度增高而下降.在无钙灌流液条件下,4-AP诱导的钙瞬变峰值水平下降,达峰时间延长,与含钙灌流液比较差异有统计学意义(P<0.05).结论 4-AP可诱导急性脑片海马CA1锥体神经

  9. Prolonged sojourn of developing pyramidal cells in the intermediate zone of the hippocampus and their settling in the stratum pyramidale

    International Nuclear Information System (INIS)

    In radiograms of rat embryos that received a single dose of [3H]thymidine between days E16 and E20 and were killed 24 hours after the injection, the heavily labeled cells (those that ceased to multiply soon after the injection) form a horizontal layer in the intermediate zone of the hippocampus, called the inferior band. The fate of these heavily labeled cells was traced in radiograms of the dorsal hippocampus in embryos that received [3H]thymidine on day E18 and were killed at different intervals thereafter. Two hours after injection the labeled proliferative cells are located in the Ammonic neuroepithelium. The heavily labeled cells that leave the neuroepithelium and aggregate in the inferior band 1 day after the injection become progressively displaced toward the stratum pyramidale 2-3 days later, and penetrate the stratum pyramidale of the CA1 region on the 4th day. In the stratum pyramidale of the CA3 region, farther removed from the Ammonic neuroepithelium, the heavily labeled cells are still sojourning in the intermediate zone 4 days after labeling. Observations in methacrylate sections suggest that two morphogenetic features of the developing hippocampus may contribute to the long sojourn of young pyramidal cells in the intermediate zone: the way in which the stratum pyramidale forms and the way in which the alveolar channels develop. The stratum pyramidale of the CA1 region forms before that of the CA3 region, which is the reverse of the neurogenetic gradient in the production of pyramidal cells. We hypothesize that this is so because the pyramidal cells destined to settle in the CA3 region, which will be contacted by granule cells axons (the mossy fibers), have to await the formation of the granular layer on days E21-E22

  10. Branching angles of pyramidal cell dendrites follow common geometrical design principles in different cortical areas

    OpenAIRE

    Concha Bielza; Ruth Benavides-Piccione; Pedro López-Cruz; Pedro Larrañaga; Javier DeFelipe

    2014-01-01

    Unraveling pyramidal cell structure is crucial to understanding cortical circuit computations. Although it is well known that pyramidal cell branching structure differs in the various cortical areas, the principles that determine the geometric shapes of these cells are not fully understood. Here we analyzed and modeled with a von Mises distribution the branching angles in 3D reconstructed basal dendritic arbors of hundreds of intracellularly injected cortical pyramidal cells in seven differen...

  11. θ frequency stimulation up-regulates the synaptic strength of the pathway from CA1 to subiculum region of hippocampus

    OpenAIRE

    Huang, Yan-You; Kandel, Eric R.

    2004-01-01

    The subiculum (SB) is the principal target of the axons of the CA1 pyramidal cells and serves as the final relay in the trisynaptic loop between the entorhinal cortex and the hippocampus. We have examined synaptic plasticity in the synaptic pathway between the CA1 pyramidal cells and the SB in hippocampal slices and compared it under the same experimental condition with the synaptic plasticity in Shaffer collateral pathway (CA3-CA1). We find that the frequency response curve of synaptic stren...

  12. Cell-Type Specific Inactivation of Hippocampal CA1 Disrupts Location-Dependent Object Recognition in the Mouse

    Science.gov (United States)

    Haettig, Jakob; Sun, Yanjun; Wood, Marcelo A.; Xu, Xiangmin

    2013-01-01

    The allatostatin receptor (AlstR)/ligand inactivation system enables potent regulation of neuronal circuit activity. To examine how different cell types participate in memory formation, we have used this system through Cre-directed, cell-type specific expression in mouse hippocampal CA1 in vivo and examined functional effects of inactivation of…

  13. Estimation of the spatial energy deposition in CA1 pyramidal neurons under exposure to 12C and 56Fe ion beams

    Directory of Open Access Journals (Sweden)

    Munkhbaatar Batmunkh

    2015-10-01

    Full Text Available The exposure to heavy charged particles represents a significant risk to the central nervous system. In experiments with rodents, the irradiation with heavy ions induces a prolonged deficit in hippocampus-dependent learning and memory. The exact nature of these violations remains mostly unclear. In this regard, the estimation of radiation effects at the level of single neurons is of our special interest. The present study demonstrates the results of comparative calculations that are performed to clarify the early physical events in single neurons under the exposure to accelerated 12C and 56Fe ions with different parameters. Using the Geant4-based Monte Carlo simulations, the radiation effects are considered in terms of energy and dose deposition. The spatial patterns of energy and dose depositions within a single neural cell are produced. As additional characteristics, the spectra of the specific energy and energy imparted are estimated. Our results show that the cell morphology is an important factor determining the accumulation of radiation dose in neurons under the exposure to heavy ions. The data obtained suggest a possibility of radiation damage to synapses that are considered to play an important role in radiation-induced violations of hippocampus-dependent learning and memory.

  14. Cell-Type-Specific Circuit Connectivity of Hippocampal CA1 Revealed through Cre-Dependent Rabies Tracing

    Directory of Open Access Journals (Sweden)

    Yanjun Sun

    2014-04-01

    Full Text Available We developed and applied a Cre-dependent, genetically modified rabies-based tracing system to map direct synaptic connections to specific CA1 neuron types in the mouse hippocampus. We found common inputs to excitatory and inhibitory CA1 neurons from CA3, CA2, the entorhinal cortex (EC, the medial septum (MS, and, unexpectedly, the subiculum. Excitatory CA1 neurons receive inputs from both cholinergic and GABAergic MS neurons, whereas inhibitory neurons receive a great majority of inputs from GABAergic MS neurons. Both cell types also receive weaker input from glutamatergic MS neurons. Comparisons of inputs to CA1 PV+ interneurons versus SOM+ interneurons showed similar strengths of input from the subiculum, but PV+ interneurons received much stronger input than SOM+ neurons from CA3, the EC, and the MS. Thus, rabies tracing identifies hippocampal circuit connections and maps how the different input sources to CA1 are distributed with different strengths on each of its constituent cell types.

  15. Dendritic branching angles of pyramidal cells across layers of the juvenile rat somatosensory cortex.

    Science.gov (United States)

    Leguey, Ignacio; Bielza, Concha; Larrañaga, Pedro; Kastanauskaite, Asta; Rojo, Concepción; Benavides-Piccione, Ruth; DeFelipe, Javier

    2016-09-01

    The characterization of the structural design of cortical microcircuits is essential for understanding how they contribute to function in both health and disease. Since pyramidal neurons represent the most abundant neuronal type and their dendritic spines constitute the major postsynaptic elements of cortical excitatory synapses, our understanding of the synaptic organization of the neocortex largely depends on the available knowledge regarding the structure of pyramidal cells. Previous studies have identified several apparently common rules in dendritic geometry. We study the dendritic branching angles of pyramidal cells across layers to further shed light on the principles that determine the geometric shapes of these cells. We find that the dendritic branching angles of pyramidal cells from layers II-VI of the juvenile rat somatosensory cortex suggest common design principles, despite the particular morphological and functional features that are characteristic of pyramidal cells in each cortical layer. J. Comp. Neurol. 524:2567-2576, 2016. © 2016 Wiley Periodicals, Inc. PMID:26850576

  16. The dendritic density field of a cortical pyramidal cell

    Directory of Open Access Journals (Sweden)

    Hermann eCuntz

    2012-02-01

    Full Text Available Much is known about the computation in individual neurons in the cortical column. Also, the selective connectivity between many cortical neuron types has been studied in great detail. But due to the complexity of this microcircuitry its functional role within the cortical column remains a mystery. Some of the wiring behavior between neurons can be interpreted directly from their particular dendritic and axonal shapes. Here, I describe the dendritic density field as one key element that remains to be better understood. I sketch an approach to relate dendritic density fields in general to their underlying potential connectivity schemes. As an example, I show how the characteristic shape of a cortical pyramidal cell appears as a direct consequence of connecting inputs arranged in two separate parallel layers.

  17. Similar GABAA receptor subunit composition in somatic and axon initial segment synapses of hippocampal pyramidal cells.

    Science.gov (United States)

    Kerti-Szigeti, Katalin; Nusser, Zoltan

    2016-01-01

    Hippocampal pyramidal cells (PCs) express many GABAAR subunit types and receive GABAergic inputs from distinct interneurons. Previous experiments revealed input-specific differences in α1 and α2 subunit densities in perisomatic synapses, suggesting distinct IPSC decay kinetics. However, IPSC decays evoked by axo-axonic, parvalbumin- or cholecystokinin-expressing basket cells were found to be similar. Using replica immunogold labeling, here we show that all CA1 PC somatic and AIS synapses contain the α1, α2, β1, β2, β3 and γ2 subunits. In CA3 PCs, 90% of the perisomatic synapses are immunopositive for the α1 subunit and all synapses are positive for the remaining five subunits. Somatic synapses form unimodal distributions based on their immunoreactivity for these subunits. The α2 subunit densities in somatic synapses facing Cav2.1 (i.e. parvalbumin) or Cav2.2 (cholecystokinin) positive presynaptic active zones are comparable. We conclude that perisomatic synapses made by three distinct interneuron types have similar GABAA receptor subunit content. PMID:27537197

  18. Increased size and stability of CA1 and CA3 place fields in HCN1 knockout mice

    OpenAIRE

    Hussaini, Syed A.; Kempadoo, Kimberly A.; Thuault, Sébastien J.; Siegelbaum, Steven A.; Kandel, Eric R.

    2011-01-01

    Hippocampal CA1 and CA3 pyramidal neuron place cells encode the spatial location of an animal through localized firing patterns called “place fields”. To explore the mechanisms that control place cell firing and their relationship to spatial memory, we studied mice with enhanced spatial memory resulting from forebrain-specific knockout of the HCN1 hyperpolarization-activated cation channel. HCN1 is strongly expressed in CA1 neurons and entorhinal cortex grid cells, which provide spatial infor...

  19. Molecular analysis of ivy cells of the hippocampal CA1 stratum radiatum using spectral identification of immunofluorophores

    Directory of Open Access Journals (Sweden)

    Jozsef Somogyi

    2012-05-01

    Full Text Available Nitric oxide synthase-expressing (NOS+ GABAergic interneurons are common in hippocampal stratum radiatum, but these cells are less well characterised than NOS+ ivy cells in stratum pyramidale or neurogliaform cells in stratum lacunosum-moleculare. Here we have studied the laminar distribution of the axons and dendrites, and the immunoreactivity of these neurons recorded in rat hippocampal slices. We have used spectral analysis of antibody- or streptavidin conjugated fluorophores to improve recognition of genuine signals in reactions for molecules such as NOS and neuropeptide-Y, when immunolabelling was low in the recorded cell. We found that most NOS+ cells with soma in the CA1 area stratum radiatum exhibit characteristic properties of ivy cells; all tested cells were positive for NPY and negative for reelin. However, laminar distributions of their neurites differ from original characterization of ivy cells with the soma close to stratum pyramidale. Both their dendrites and axon are mainly in stratum radiatum and to a lesser extent in stratum oriens. In addition, both the dendrites and axons often extend to stratum lacunosum-moleculare. We conclude that ivy cells in stratum radiatum are predominantly feedforward inhibitory interneurons in the CA1 area, and their axonal output delivering GABA, NPY and NO can influence both the entorhinal cortex innervated and the CA3 innervated zones pre- and postsynaptically. Spectral analysis of fluorophores provides an objective algorithm to analyze signals in immunoreactions for neurochemical markers.

  20. Distinguishing linear vs. nonlinear integration in CA1 radial oblique dendrites: it’s about time

    Directory of Open Access Journals (Sweden)

    José Francisco eGómez González

    2011-11-01

    Full Text Available It was recently shown that multiple excitatory inputs to CA1 pyramidal neuron dendrites must be activated nearly simultaneously to generate local dendritic spikes and superlinear responses at the soma; even slight input desynchronization prevented local spike initiation (Gasparini, 2006;Losonczy, 2006. This led to the conjecture that CA1 pyramidal neurons may only express their nonlinear integrative capabilities during the highly synchronized sharp waves and ripples that occur during slow wave sleep and resting/consummatory behavior, whereas during active exploration and REM sleep (theta rhythm, inadequate synchronization of excitation would lead CA1 pyramidal cells to function as essentially linear devices. Using a detailed single neuron model, we replicated the experimentally observed synchronization effect for brief inputs mimicking single synaptic release events. When synapses were driven instead by double pulses, more representative of the bursty inputs that occur in vivo, we found that the tolerance for input desynchronization was increased by more than an order of magnitude. The effect depended mainly on paired pulse facilitation of NMDA receptor-mediated responses at Schaffer collateral synapses. Our results suggest that CA1 pyramidal cells could function as nonlinear integrative units in all major hippocampal states.

  1. Neuronal chromatin changes in layer V pyramidal cells of somatomotor cortex after pyramidal tract lesions as demonstrated by [3H]actinomycin D binding

    International Nuclear Information System (INIS)

    Changes in chromatin structure of pyramidal tract neurons after medullary pyramidal tract lesions were examined autoradiographically utilizing [3H]actinomycin D (Act D) binding to nuclei in frozen sections of brain. After a right pyramidal tract lesion, the binding of Act D to nuclei of axotomized pyramidal neurons of somatomotor cortex layer V increased sharply at 1 and 5 days postoperation, compared with pyramidal cells of the left side or hippocampal control cells of the left hemisphere. At 3, 7, 9, and 11 days the axotomized cells showed significantly decreased binding compared with controls. The unoperated pyramidal cells showed a significantly decreased Act D binding at 2 h and 9 days postoperation compared with the ipsilateral hippocampal control cells. The data suggested that intrinsic neurons of the central nervous system had a response pattern of chromatin changes to axotomy that was basically similar to that of peripheral neurons (sensory ganglion cells). However, the response was compressed into the 1st week postoperation with only a brief reaction which might be correlated to axonal regeneration. This reaction was followed by a prolonged depression of Act D nuclear binding which may be associated with cellular atrophy

  2. Pyramidal cells in prefrontal cortex: comparative observations reveal unparalleled specializations in neuronal structure among primate species.

    Directory of Open Access Journals (Sweden)

    Guy eElston

    2011-02-01

    Full Text Available The most ubiquitous neuron in the cerebral cortex, the pyramidal cell, is characterised by markedly different dendritic structure among different cortical areas. The complex pyramidal cell phenotype in granular prefrontal cortex (gPFC of higher primates endows specific biophysical properties and patterns of connectivity, which differ to those in other cortical regions. However, within the gPFC, data have been sampled from only a select few cortical areas. The gPFC of species such as human and macaque monkey includes more than 10 cortical areas. It remains unknown as to what degree pyramidal cell structure may vary among these cortical areas. Here we undertook a survey of pyramidal cells in the dorsolateral, medial and orbital gPFC of cercopethicid primates. We found marked heterogeneity in pyramidal cell structure within and between these regions. Moreover, trends for gradients in neuronal complexity varied among species. As neuron structure determines it’s computational abilities and memory storage capacity and connectivity, we propose that these specializations in the pyramidal cell phenotype are an important determinant of species specific executive cortical functions in primates.

  3. Pyramid shape of polymer solar cells: a simple solution to triple efficiency

    International Nuclear Information System (INIS)

    Pyramid-shaped polymer solar cells fabricated on flexible substrates were investigated. Effective light trapping can be realized due to light reflection in all 360° directions, and 100% space utilization is achieved when assembled into arrays. The power conversion efficiency is enhanced by 200% ([60]PCBM as the acceptor) and 260% ([70]PCBM as the acceptor) with a dihedral angle of 30° between the opposite sides of the pyramid compared with a planar device, and a high Voc of 3.5 V in series connection is obtained. Considering the material utilization, an angle of 90° for pyramid-shaped polymer solar cells is proposed. Pyramid-shaped polymer solar cells are particularly suitable for installation on roof of vehicles and houses, which have limited surface area. (paper)

  4. Effect of bone marrow stromal cell transplantation to the hippocampal CA1 region on electroencephalographic activity in epileptic rats

    Institute of Scientific and Technical Information of China (English)

    Hong Xu; Guowei Xu; Zhongtang Feng; Tinghua Wang; Jia Yang; Qingying Wu; Zhicheng Xiao

    2008-01-01

    BACKGROUND: Animal experiments have confirmed that bone marrow stromal cell (BMSC) transplantation can serve as a treatment for epilepsy.OBJECTIVE: BMSCs derived from green fluorescent protein (GFP) mice were transplanted into the hippocampal CA1 region of epileptic rats. The aim of the study was to record electroencephalogram (EEG), analyze survival and migration of BMSCs, and validate the effect of BMSC transplantation for the treatment of epilepsy.DESIGN, TIME AND SETTING: A randomized block design experiment was performed at the Institute of Neuroscience, Kunming Medical College from March 200.5 to February 2006.MATERIALS: Homozygous C57BL/6CrSIcTgN (acr-EGFP) OsbC 14-Y01 -FM 131 mice, 8-12 weeks of age, were selected for preparation of cell suspension. Sprague Dawley rats were selected for establishing epilepsy models.METHODS: Rats were randomly divided into 4 groups: control (n = 8), model (n = 8), normal saline (n = 24), and BMSC (n = 24). In the model, normal saline, and BMSC groups, epilepsy was established with penicillin (3×107 U/kg i.p. ×7 days). Rats in the BMSC group received a BMSC suspension derived fromgreen fluorescent protein mice into the right hippocampal CA1 region. Rats in the vehicle control group were injected with the same volume of normal saline into the hippocampal CA1 region.MAIN OUTCOME MEASURES: The electroencephalogram was used to monitor brain activity. Survival and migration of the transplanted BMSCs was observed using fluorescence microscopy at 1, 2, and 4 weeks after transplantation.RESULTS: In BMSC group, fluorescent cells were observed at the transplantation site and in the adjacent tissue, as well as in the tissue surrounding the needle tract, indicating the migration of implanted cells. Fluorescent cells were not detected in the vehicle control group. The electroencephalogram of the control animals exhibited 7-9 Hz α waves, with a wave amplitude < 50 μ V. In the model and vehicle control groups, random spike

  5. Improvement of quantum efficiency using surface texture of solar cell in the form of pyramid

    International Nuclear Information System (INIS)

    The work presented in this paper concerns a detailed study about the light transmission through textured surfaces in a surface made up of pyramids [1, 2]. We investigate to what extent and under what conditions we want to take advantage of ray incidence five times and more [3, 4]. It is found that these analyses can be used to determine the optimal surface texture, which provides the best light trapping for solar cells in terms of the total internal reflection occurring in the high-index medium at incidence angles larger than the nominal critical angle [5-11]. One of the main contributions of this paper is the analysis and quantification of the influence of the opening between the heads of the two closest pyramids in textured surface for solar cells and its application to the photovoltaic parameters, such as the quantum efficiency. In this model, we show that the material can have five and more successive incident ray absorptions instead of three currently, where we changed the direction of the reflected ray, by varying the angle between the two neighbouring pyramids, the incidence angle, the opening between the heads of the two closest pyramids and their height. Thus, an angle between the two neighbouring pyramids varies between 20 and 12° and an angle of incidence varies between 80 and 84°. For these values of the angle between the two neighbouring pyramids and incidence angle, the opening between the heads of the two closest pyramids varied respectively from 3.53 to 2.10 μm for a pyramid height of 10 μm. This leads to a substantial increase of the quantum efficiency, thus the photovoltaic efficiency

  6. The mammalian neocortical pyramidal cell: a new theory on prenatal development

    Directory of Open Access Journals (Sweden)

    Miguel eMarín-Padilla

    2014-01-01

    Full Text Available Mammals’ new cerebral cortex (neocortex and the new type of pyramidal neuron are mammalian innovations that have evolved for operating their increasing motor capabilities using essentially analogous anatomical and neural makeups. The human neocortex starts to develop in the 6-week-old embryo with the establishment of a primordial cortical organization that resembles the primitive cortices of amphibian and reptiles that operated his early motor activities. From the 8th to the 15th week of age, the new pyramidal neurons, of ependymal origin, are progressively incorporated within this primordial cortex forming a cellular plate that divide its components into those above it (neocortex first lamina and those below it (neocortex subplate elements. From the 16th week of age to birth and postnatally, the new pyramidal neurons continue to elongate functionally their apical dendrite by adding synaptic membrane to incorporate the needed sensory information for operating the animal muscular activities. The new pyramidal neuron’ distinguishing feature is the capacity of elongating anatomically and functionally its apical dendrite (its main receptive surface without losing its original attachment to first lamina or the location of its soma retaining its essential nature. The number of pyramidal cell functional strata established in the motor cortex increases and reflects each mammalian species motor capabilities: the hedgehog needs 2 pyramidal cell functional strata to carry out all its motor activities, the mouse three, cat four, primates 5 and humans 6. The presence of six pyramidal cell functional strata distinguish the human motor cortex from that of others primates. Homo sapiens represent a new evolutionary stage that have transformed his primate brain for operating his unique motor capabilities, such as speaking, writing, painting, sculpturing including thinking as a premotor activity.

  7. Broadband Absorption Enhancement in Thin Film Solar Cells Using Asymmetric Double-Sided Pyramid Gratings

    Science.gov (United States)

    Alshal, Mohamed A.; Allam, Nageh K.

    2016-07-01

    A design for a highly efficient modified grating crystalline silicon (c-Si) thin film solar cell is demonstrated and analyzed using the two-dimensional (2-D) finite element method. The suggested grating has a double-sided pyramidal structure. The incorporation of the modified grating in a c-Si thin film solar cell offers a promising route to harvest light into the few micrometers active layer. Furthermore, a layer of silicon nitride is used as an antireflection coating (ARC). Additionally, the light trapping through the suggested design is significantly enhanced by the asymmetry of the top and bottom pyramids. The effects of the thickness of the active layer and facet angle of the pyramid on the spectral absorption, ultimate efficiency (η), and short-circuit current density (J sc) are investigated. The numerical results showed 87.9% efficiency improvement over the conventional thin film c-Si solar cell counterpart without gratings.

  8. Endocannabinoid release modulates electrical coupling between CCK cells connected via chemical and electrical synapses in CA1

    Directory of Open Access Journals (Sweden)

    Jonathan eIball

    2011-11-01

    Full Text Available Electrical coupling between some subclasses of interneurons is thought to promote coordinated firing that generates rhythmic synchronous activity in cortical regions. Synaptic activity of cholesystokinin (CCK interneurons which co-express cannbinoid type-1 (CB1 receptors are powerful modulators of network activity via the actions of endocannabinoids. We investigated the modulatory actions of endocannabinoids between chemically and electrically connected synapses of CCK cells using paired whole-cell recordings combined with biocytin and double immunofluorescence labelling in acute slices of rat hippocampus at P18-20 days. CA1 stratum radiatum CCK Schaffer collateral associated (SCA cells were coupled electrically with each other as well as CCK basket cells and CCK cells with axonal projections expanding to dentate gyrus. Approximately 50% of electrically coupled cells received facilitating, asynchronously released IPSPs that curtailed the steady-state coupling coefficient by 57%. Tonic CB1 receptor activity which reduces inhibition enhanced electrical coupling between cells that were connected via chemical and electrical synapses. Blocking CB1 receptors with antagonist, AM-251 (5M resulted in the synchronized release of larger IPSPs and this enhanced inhibition further reduced the steady-state coupling coefficient by 85%. Depolarization induced suppression of inhibition (DSI, maintained the asynchronicity of IPSP latency, but reduced IPSP amplitudes by 95% and enhanced the steady-state coupling coefficient by 104% and IPSP duration by 200%. However, DSI did not did not enhance electrical coupling at purely electrical synapses. These data suggest that different morphological subclasses of CCK interneurons are interconnected via gap junctions. The synergy between the chemical and electrical coupling between CCK cells probably plays a role in activity-dependent endocannabinoid modulation of rhythmic synchronization.

  9. Thyroid Metastasis in Pyramidal Lobe from Renal Cell Carcinoma: A Case Report

    International Nuclear Information System (INIS)

    Thyroid metastasis is rare. The most common primary malignancy of thyroid metastasis worldwide is known to be renal cell carcinoma, but the most common primary malignancy in South Korea is breast cancer. Many studies have reported that primary renal cell carcinoma is almost unilateral and thyroid metastasis from renal cell carcinoma is a nearly ipsilateral, single lesion. We report a case of pyramidal lobe metastasis from renal cell carcinoma.

  10. Thyroid Metastasis in Pyramidal Lobe from Renal Cell Carcinoma: A Case Report

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Hyung Seok; Kim, Dong Wook; Kim, Sang Su [Dept. of Radiology, Busan Paik Hospital, Inje University College of Medicine, Busan (Korea, Republic of); Jung, Soo Jin [Dept. of Pathology, Busan Paik Hospital, Inje University College of Medicine, Busan (Korea, Republic of)

    2011-06-15

    Thyroid metastasis is rare. The most common primary malignancy of thyroid metastasis worldwide is known to be renal cell carcinoma, but the most common primary malignancy in South Korea is breast cancer. Many studies have reported that primary renal cell carcinoma is almost unilateral and thyroid metastasis from renal cell carcinoma is a nearly ipsilateral, single lesion. We report a case of pyramidal lobe metastasis from renal cell carcinoma.

  11. Gap junctions between CA3 pyramidal cells contribute to network synchronization in neonatal hippocampus.

    Science.gov (United States)

    Molchanova, Svetlana M; Huupponen, Johanna; Lauri, Sari E; Taira, Tomi

    2016-08-01

    Direct electrical coupling between neurons through gap junctions is prominent during development, when synaptic connectivity is scarce, providing the additional intercellular connectivity. However, functional studies of gap junctions are hampered by the unspecificity of pharmacological tools available. Here we have investigated gap-junctional coupling between CA3 pyramidal cells in neonatal hippocampus and its contribution to early network activity. Four different gap junction inhibitors, including the general blocker carbenoxolone, decreased the frequency of network activity bursts in CA3 area of hippocampus of P3-6 rats, suggesting the involvement of electrical connections in the generation of spontaneous network activity. In CA3 pyramidal cells, spikelets evoked by local stimulation of stratum oriens, were inhibited by carbenoxolone, but not by inhibitors of glutamatergic and GABAergic synaptic transmission, signifying the presence of electrical connectivity through axo-axonic gap junctions. Carbenoxolone also decreased the success rate of firing antidromic action potentials in response to stimulation, and changed the pattern of spontaneous action potential firing of CA3 pyramidal cells. Altogether, these data suggest that electrical coupling of CA3 pyramidal cells contribute to the generation of the early network events in neonatal hippocampus by modulating their firing pattern and synchronization. PMID:26926429

  12. Pyramidal cell development: postnatal spinogenesis, dendritic growth, axon growth, and electrophysiology.

    Directory of Open Access Journals (Sweden)

    Guy eElston

    2014-08-01

    Full Text Available Here we review recent findings related to postnatal spinogenesis, dendritic and axon growth, pruning and electrophysiology of neocortical pyramidal cells in the developing primate brain. Pyramidal cells in sensory, association and executive cortex grow dendrites, spines and axons at different rates, and vary in the degree of pruning. Of particular note is the fact that pyramidal cells in primary visual area (V1 prune more spines than they grow during postnatal development, whereas those in inferotemporal (TEO and TE and granular prefrontal cortex (gPFC; Brodmann’s area 12 grow more than they prune. Moreover, pyramidal cells in TEO, TE and the gPFC continue to grow larger dendritic territories from birth into adulthood, replete with spines, whereas those in V1 become smaller during this time. The developmental profile of intrinsic axons also varies between cortical areas: those in V1, for example, undergo an early proliferation followed by pruning and local consolidation into adulthood, whereas those in area TE tend to establish their territory and consolidate it into adulthood with little pruning. We correlate the anatomical findings with the electrophysiological properties of cells in the different cortical areas, including membrane time constant, depolarizing sag, duration of individual action potentials, and spike-frequency adaptation. All of the electrophysiological variables ramped up before 7 months of age in V1, but continued to ramp up over a protracted period of time in area TE. These data suggest that the anatomical and electrophysiological profiles of pyramidal cells vary among cortical areas at birth, and continue to diverge into adulthood. Moreover, the data reveal that the use it or lose it notion of synaptic reinforcement may speak to only part of the story, use it but you still might lose it may be just as prevalent in the cerebral cortex.

  13. Pyramidal texturing of silicon surface via inorganic-organic hybrid alkaline liquor for heterojunction solar cells

    Science.gov (United States)

    Wang, Fengyou; Zhang, Xiaodan; Wang, Liguo; Jiang, Yuanjian; Wei, Changchun; Zhao, Ying

    2015-10-01

    We demonstrate a new class of silicon texturing approach based on inorganic (sodium hydroxide, NaOH) and organic (tetramethylammonium hydroxide, TMAH) alkaline liquor etching processes for photovoltaic applications. The first stage of inorganic alkaline etching textures the silicon surface rapidly with large pyramids and reduces the cost. The subsequent organic alkaline second-etching improves the coverage of small pyramids on the silicon surface and strip off the metallic contaminants produced by the first etching step. In addition, it could smoothen the surface of the pyramids to yield good morphology. In this study, the texturing duration of both etching steps was controlled to optimize the optical and electrical properties as well as the surface morphology and passivation characteristics of the silicon substrates. Compared with traditional inorganic NaOH texturing, this hybrid process yields smoother (111) facets of the pyramids, fewer residual Na+ ions on the silicon surface, and a shorter processing period. It also offers the advantage of lower cost compared with the organic texturing method based on the use of only TMAH. We applied this hybrid texturing process to fabricate silicon heterojunction solar cells, which showed a remarkable improvement compared with the cells based on traditional alkaline texturing processes.

  14. Pyramidal cells in V1 of African rodents are bigger more branched and more spiny than those in primates.

    Directory of Open Access Journals (Sweden)

    Guy Elston

    2014-02-01

    Full Text Available Pyramidal cells are characterised by markedly different sized dendritic trees, branching patterns and spine density across the cortical mantle. Moreover, pyramidal cells have been shown to differ in structure among homologous cortical areas in different species; however, most of these studies have been conducted in primates. Whilst pyramidal cells have been quantified in a few cortical areas in some other species there are, as yet, no uniform comparative data on pyramidal cell structure in a homologous cortical area among species in different Orders. Here we studied layer III pyramidal cells in V1 of three species of rodents, the greater cane rat, highveld gerbil and four-striped mouse, by the same methodology used to sample data from layer III pyramidal cells in primates. The data reveal markedly different trends between rodents and primates: there is an appreciable increase in the size, branching complexity and number of spines in the dendritic trees of pyramidal cells with increasing size of V1 in the brain in rodents, whereas there is relatively little difference in primates. Moreover, pyramidal cells in rodents are larger, more branched and more spinous than those in primates. For example, the dendritic trees of pyramidal cells in V1 of the cane rat are nearly three times larger, and have more than ten times the number of spines in their basal dendritic trees, than those in V1 of the macaque (7900 and 600, respectively, which has a V1 40 times the size that of the cane rat. It remains to be determined to what extent these differences may result from developmental differences or reflect evolutionary and/or processing specializations.

  15. Differences in etching characteristics of TMAH and KOH on preparing inverted pyramids for silicon solar cells

    Science.gov (United States)

    Fan, Yujie; Han, Peide; Liang, Peng; Xing, Yupeng; Ye, Zhou; Hu, Shaoxu

    2013-01-01

    In this paper, a series of comparative etching experiments on preparing inverted pyramids of silicon solar cells have been carried out using tetramethyl ammonium hydroxide (TMAH) and potassium hydroxide (KOH) at different etchant concentrations and temperatures on a patterned (1 0 0) Si. These experiment results show that TMAH solution has higher undercut rate and lower (1 0 0) plane etch rate than KOH solution, and the (1 1 1)/(1 0 0) etch rate ratio of TMAH is two to three times that of KOH solution. Additionally, etch rate of SiO2 mask is an order of magnitude lower in TMAH than in KOH. Besides, surface morphology analysis indicates that TMAH etching can obtain much higher quality inverted pyramids of sharp vertex, smooth (1 1 1) sidewall and uncontaminated surface than KOH etching, which makes TMAH etching samples show better antireflection properties. Finally, the minimum reflectivity of TMAH etching sample low as 1.8% is obtained for inverted pyramids covered with SiO2 reflectivity coating. So the study reveals that TMAH is more attractive for the preparation of inverted pyramids than KOH.

  16. Unsupervised classification of cell images using pyramid node linking.

    Science.gov (United States)

    Arman, F; Pearce, J A

    1990-06-01

    In this communication we describe a segmentation technique which combines two properties in an iterative and hierarchial matter to correctly segment and classify the given cell images. The technique is applied to digital images taken from microscope slides of cultured rat liver cells, and the goal is to classify these cells into one of three possible classes. The first class cells (I) are morphologically normal and stain the darkest. The second class cells (II) are slightly damaged showing both nuclear and cytoplasmic swelling with resultant lessening of staining affinity. The third class cells (III) are markedly damaged as demonstrated by the presence of cytoplasmic vacuolization, or are completely disintegrated. First class cells are classified by taking advantage of their staining affinity; the original gray level image is segmented into four gray levels. The darkest is then classified as type I. Type III cells are classified by using high business as a characteristic; the standard deviation of the original image is segmented into four business levels. The highest level is classified as type III cell. Assuming only the three cell types are present in any given image, the remaining non-background unclassified pixels are determined to belong to type II cells. PMID:2191915

  17. Monosynaptic excitatory transmission from the hippocampal CA1 region to the subiculum.

    Science.gov (United States)

    Geng, Xiaoqi; Mori, Masahiro

    2015-09-14

    The subiculum is a major output region of the hippocampus, receiving inputs from the CA1 region. We obtained paired patch-clamp recordings from synaptically coupled pairs of CA1 pyramidal cells (CA1PCs) and subicular principal cells (SubPCs), using rat hippocampal organotypic slice cultures. A single action potential in a presynaptic CA1PC evoked a unitary excitatory postsynaptic current in a SubPC (EPSCCA1→Sub). The failure rate of the monosynaptic transmission was remarkably low (0.08). Paired-pulse depression in SubPCs was apparent when an interval of presynaptic action potentials was shorter than 50ms. When trains of action potentials were induced in a CA1PC, EPSCCA1→Sub was significantly depressed with increasing spike frequency (20-100Hz). Thus the unitary monosynaptic transmission from a CA1PC to a SubPC is reliable, and depressed in response to frequent inputs, suggesting that the subiculum may function as a low pass filter to provide the downstream brain regions with appropriate information. PMID:26232683

  18. Description of morphological changes in neurons and endothelial cells of CA1-area of hippocampus in rats with alloxan-induced hyp erglycemia under application of nootropic drugs

    OpenAIRE

    Zhylyuk V.I.; Mamchur V.I.

    2012-01-01

    Using neuromorphometry analysis differences in the effects of nootropic drugs on morphology and function of neurons and endothelial cells of hippocampus, content of RNA, content of apoptotic and destructive neurons were examined in white rats with chronic alloxan-induced hyperglycemia. It ha s been found that diabetes in rats is accompanied by specific morphological and functional changes and activation of apoptosis in neurons of the CA1-area in hi ppocampus, which may be related to disturb...

  19. Upregulated H-Current in hyperexcitable CA1 dendrites after febrile seizures

    Directory of Open Access Journals (Sweden)

    Jonas Dyhrfjeld-Johnsen

    2008-04-01

    Full Text Available Somatic recordings from CA1 pyramidal cells indicated a persistent upregulation of the h-current (Ih after experimental febrile seizures. Here, we examined febrile seizure-induced long-term changes in Ih and neuronal excitability in CA1 dendrites. Cell-attached recordings showed that dendritic Ih was significantly upregulated, with a depolarized half-activation potential and increased maximal current. Although enhanced Ih is typically thought to be associated with decreased dendritic excitability, whole-cell dendritic recordings revealed a robust increase in action potential firing after febrile seizures. We turned to computational simulations to understand how the experimentally observed changes in Ih influence dendritic excitability. Unexpectedly, the simulations, performed in three previously published CA1 pyramidal cell models, showed that the experimentally observed increases in Ih resulted in a general enhancement of dendritic excitability, primarily due to the increased Ih-induced depolarization of the resting membrane potential overcoming the excitability-depressing effects of decreased dendritic input resistance. Taken together, these experimental and modeling results reveal that, contrary to the exclusively anti-convulsive role often attributed to increased Ih in epilepsy, the enhanced Ih can co-exist with, and possibly even contribute to, persistent dendritic hyperexcitability following febrile seizures in the developing hippocampus.

  20. Sublayer-Specific Coding Dynamics during Spatial Navigation and Learning in Hippocampal Area CA1.

    Science.gov (United States)

    Danielson, Nathan B; Zaremba, Jeffrey D; Kaifosh, Patrick; Bowler, John; Ladow, Max; Losonczy, Attila

    2016-08-01

    The mammalian hippocampus is critical for spatial information processing and episodic memory. Its primary output cells, CA1 pyramidal cells (CA1 PCs), vary in genetics, morphology, connectivity, and electrophysiological properties. It is therefore possible that distinct CA1 PC subpopulations encode different features of the environment and differentially contribute to learning. To test this hypothesis, we optically monitored activity in deep and superficial CA1 PCs segregated along the radial axis of the mouse hippocampus and assessed the relationship between sublayer dynamics and learning. Superficial place maps were more stable than deep during head-fixed exploration. Deep maps, however, were preferentially stabilized during goal-oriented learning, and representation of the reward zone by deep cells predicted task performance. These findings demonstrate that superficial CA1 PCs provide a more stable map of an environment, while their counterparts in the deep sublayer provide a more flexible representation that is shaped by learning about salient features in the environment. VIDEO ABSTRACT. PMID:27397517

  1. Time- and cell-type specific changes in iron, ferritin, and transferrin in the gerbil hippocampal CA1 region after transient forebrain ischemia

    Science.gov (United States)

    Yoo, Dae Young; Yoo, Ki-Yeon; Park, Joon Ha; Kwon, Hyun Jung; Jung, Hyo Young; Kim, Jong Whi; Choi, Goang-Min; Moon, Seung Myung; Kim, Dae Won; Yoon, Yeo Sung; Won, Moo-Ho; Hwang, In Koo

    2016-01-01

    In the present study, we used immunohistochemistry and western blot analysis to examine changes in the levels and cellular localization of iron, heavy chain ferritin (ferritin-H), and transferrin in the gerbil hippocampal CA1 region from 30 minutes to 7 days following transient forebrain ischemia. Relative to sham controls, iron reactivity increased significantly in the stratum pyramidale and stratum oriens at 12 hours following ischemic insult, transiently decreased at 1–2 days and then increased once again within the CA1 region at 4–7 days after ischemia. One day after ischemia, ferritin-H immunoreactivity increased significantly in the stratum pyramidale and decreased at 2 days. At 4–7 days after ischemia, ferritin-H immunoreactivity in the glial components in the CA1 region was significantly increased. Transferrin immunoreactivity was increased significantly in the stratum pyramidale at 12 hours, peaked at 1 day, and then decreased significantly at 2 days after ischemia. Seven days after ischemia, Transferrin immunoreactivity in the glial cells of the stratum oriens and radiatum was significantly increased. Western blot analyses supported these results, demonstrating that compared to sham controls, ferritin H and transferrin protein levels in hippocampal homogenates significantly increased at 1 day after ischemia, peaked at 4 days and then decreased. These results suggest that iron overload-induced oxidative stress is most prominent at 12 hours after ischemia in the stratum pyramidale, suggesting that this time window may be the optimal period for therapeutic intervention to protect neurons from ischemia-induced death.

  2. A simulation study on the effects of dendritic morphology on layer V PFC pyramidal cell firing behavior

    Directory of Open Access Journals (Sweden)

    Maria Psarrou

    2014-03-01

    Full Text Available The majority of neuronal cells found in the cerebral cortex are pyramidal neurons. Their function has been associated with higher cognitive and emotional functions. Pyramidal neurons have a characteristic structure, consisting of a triangular shaped soma whereon descend two extended and complex dendritic trees, and a long bifurcated axon. All the morphological components of the pyramidal neurons exhibit significant variability across different brain areas and layers. Pyramidal cells receive numerous synaptic inputs along their structure, integration of which in space and in time generates local dendritic spikes that shape their firing pattern. In addition, synaptic integration is influenced by voltage-gated and ion channels, which are expressed in a large repertoire by pyramidal neurons. Electrophysiological categories of pyramidal cells can be established, based on the action potential frequency, generated from a fixed somatic stimulus: (1 cells that fire repetitive action potentials (Regular Spiking – RS, (2 cells that fire clusters of 2 – 5 action potentials with short ISIs (Intrinsic Bursting – IB, and (3 cells that fire in repetitive clusters of 2 – 5 action potentials with short ISIs (Repetitive Oscillatory Bursts – ROB. In vitro and in silico scientific studies, correlate the firing patterns of the pyramidal neurons to their morphological features. This study provides a quantitatively analysis via compartmental neuronal modelling of the effects of dendritic morphology and distribution and concentration of ionic mechanisms, along the basal and/or apical dendrites on the firing behavior of a 112-set of layer V rat PFC pyramidal cells. We focus on how particular morphological and passive features of the dendritic trees shape the neuronal firing patterns. Our results suggest that specific morphological parameters (such as total length, volume and branch number can discriminate the cells as RS or IB, regardless of what is the

  3. Effects of glossy privet fruit on neural cell apoptosis in the cortical parietal lobe and hippocampal CA1 region of vascular dementia rats

    Institute of Scientific and Technical Information of China (English)

    Jing Cai; Fan Zhou; Jian Du

    2008-01-01

    BACKGROUND: Glossy privet fruit inhibits neural cell apoptosis following the onset of vascular dementia. OBJECTIVE: To confirm glossy privet fruit effects on neural cell apoptosis in the cortical parietal lobe and hippocampal CA1 region of rat models of vascular dementia using molecular biology techniques. DESIGN, TIME AND SETTING: The neural cell morphology experiment was performed at the Laboratory of Flow Cells and Biochemistry, Academy of Integrative Medicine, Fujian University of Traditional Chinese Medicine, and the Basic Room of Pathology, Academy of Chinese Medicine from December 2006 to May 2008.MATERIALS: A total of 60 Wistar rats were used to establish vascular dementia models using a photochemical reaction method. Glossy privet fruit was purchased from Fujian, China. Hydergine was co-produced by Sandoz, Switzerland and Huajin, China. METHODS: The 60 Wistar rats were randomly divided into 6 equal sized groups (n = 10), I.e. Model, blank, high, moderate and low doses of Chinese medicine, and hydergine control groups. Rats in the model group were treated with distilled water (1 mL/100 g) by gavage following model establishment. Rats in the blank group underwent experimental procedures as for the model group, except that rat models were created without illumination. Rats in the high, moderate and low doses of Chinese medicine groups, and the hydergine control group respectively received high, moderate and low doses of glossy privet fruit, and hydergine suspension (1 mL/100 g) by gavage, once a day, for 30 days. MAIN OUTCOME MEASURES: Morphology of neural cells from the rat cortical parietal lobe and hippocampal CA1 region of all groups was observed with an electron microscope. Positive neural cells in the injury site of the rat cortical parietal lobe and hippocampal CA1 region were investigated using the Fas immunohistochemical method. Absorbance of Fas-positive neurons was detected by the MPIAS-500 multimedia color imaging analysis system. RESULTS: Neural

  4. Description of morphological changes in neurons and endothelial cells of CA1-area of hippocampus in rats with alloxan-induced hyp erglycemia under application of nootropic drugs

    Directory of Open Access Journals (Sweden)

    Zhylyuk V.I.

    2012-01-01

    Full Text Available Using neuromorphometry analysis differences in the effects of nootropic drugs on morphology and function of neurons and endothelial cells of hippocampus, content of RNA, content of apoptotic and destructive neurons were examined in white rats with chronic alloxan-induced hyperglycemia. It ha s been found that diabetes in rats is accompanied by specific morphological and functional changes and activation of apoptosis in neurons of the CA1-area in hi ppocampus, which may be related to disturbance of local blood flow due to endothelial damage. N-carbamoyl-methyl-4-phenyl-2-pyrrolidone (entrop, N-phenylacetyl-L-prolylglycine (noopept, pramiracetam, cerebrocurin and citicoline show protective effects on neurons and endothelial cells, which are much larger in force than effect s of ginkgo biloba extract, piracetam and pentoxifylline. This protective activity is characterized by reducing the number of apoptotic and dest ructive neurons in hippocampal CA1-area, increasing the density of functioning nerve and endothelial cells, activation of RNA biosynthesis in the neurocytes and endo-thelial cells

  5. Sustained increase of spontaneous input and spike transfer in the CA3-CA1 pathway following long term potentiation in vivo

    Directory of Open Access Journals (Sweden)

    Oscar eHerreras

    2012-10-01

    Full Text Available Long term potentiation (LTP is commonly used to study synaptic plasticity but the associated changes in the spontaneous activity of individual neurons or the computational properties of neural networks in vivo remain largely unclear. The multisynaptic origin of spontaneous spikes makes difficult estimating the impact of a particular potentiated input. Accordingly, we adopted an approach that isolates pathway-specific postsynaptic activity from raw local field potentials (LFPs in the rat hippocampus in order to study the effects of LTP on ongoing spike transfer between cell pairs in the CA3-CA1 pathway. CA1 Schaffer-specific LFPs elicited by spontaneous clustered firing of CA3 pyramidal cells involved a regular succession of elementary micro-field-EPSPs (gamma-frequency that fired spikes in CA1 units. LTP increased the amplitude but not the frequency of these ongoing excitatory quanta. Also, the proportion of Schaffer-driven spikes in both CA1 pyramidal cells and interneurons increased in a cell-specific manner only in previously connected CA3-CA1 cell pairs, i.e., when the CA3 pyramidal cell had shown pre-LTP significant correlation with firing of a CA1 unit and potentiated spike-triggered average of Schaffer LFPs following LTP. Moreover, LTP produced subtle reorganization of presynaptic CA3 cell assemblies. These findings show effective enhancement of pathway specific ongoing activity which leads to increased spike transfer in potentiated segments of a network. These indicate that plastic phenomena induced by external protocols may intensify spontaneous information flow across specific channels as proposed in transsynaptic propagation of plasticity and synfire chain hypotheses that may be the substrate for different types of memory involving multiple brain structures.

  6. Formation of Various Pyramidal Structures on Monocrystalline Silicon Surface and Their Influence on the Solar Cells

    Directory of Open Access Journals (Sweden)

    Yangang Han

    2013-01-01

    Full Text Available Texturization is a useful method to enhance the optical absorption of monocrystalline silicon wafers by light-trapping effect in solar cell processing. In present study, a series of textured wafers with various pyramid sizes ranging from 200 nm to 10 μm were fabricated by modified wet-chemical method and characterized. The results show that there is little difference in the reflectance with the pyramid sizes from 1 to 10 μm, which is consistent with the ray-tracing simulation results. However, the light-trapping function of the 200 nm sample below the geometrical optics limit is much weaker. The solar cells fabricated from the 1 μm samples own the highest power conversion efficiency of 18.17% due to a better coverage of metal finger lines than the larger ones, and the 200 nm samples have the lowest efficiency of 10.53%.

  7. Centered Pyramids

    OpenAIRE

    Brigger, P.; F. Müller; Illgner, K.; Unser, M.

    1999-01-01

    Quadtree-like pyramids have the advantage of resulting in a multiresolution representation where each pyramid node has four unambiguous parents. Such a centered topology guarantees a clearly defined up-projection of labels. This concept has been successfully and extensively used in applications of contour detection, object recognition and segmentation. Unfortunately, the quadtree-like type of pyramid has poor approximation powers because of the employed piecewise-constant image model. This pa...

  8. Activity-based anorexia during adolescence disrupts normal development of the CA1 pyramidal cells in the ventral hippocampus of female rats

    OpenAIRE

    Chowdhury, Tara G.; Ríos, Mariel B.; Chan, Thomas E.; Barbarich-Marsteller, Nicole C.; Aoki, Chiye

    2014-01-01

    Anorexia nervosa (AN) is a psychiatric illness characterized by restricted eating and irrational fears of gaining weight. There is no accepted pharmacological treatment for AN, and AN has the highest mortality rate among psychiatric illnesses. Anorexia nervosa most commonly affects females during adolescence, suggesting an effect of sex and hormones on vulnerability to the disease. Activity-based anorexia (ABA) is a rodent model of AN that shares symptoms with AN, including over-exercise, ele...

  9. Atypical pyramidal cells in epileptic human cortex: CFLS and 3-D reconstructions.

    Science.gov (United States)

    Belichencko, P; Dahlström, A; von Essen, C; Lindström, S; Nordborg, C; Sourander, P

    1992-09-01

    Epileptic temporal cortices, removed from 3 patients with intractable partial epilepsy (IPE) during neurosurgery, were studied. Pyramidal neurons (40-50 per slice) in laminae III, V and white matter, were injected with lucifer yellow. Samples were examined in a confocal laser scanning microscope (Biorad 600) and individual cells scanned at 0.1-1 microns incremental levels. 2-D maximal linear projection was used for overview. Frames (50-60) of scanned neurons were transformed into 3-D volumes, using VoxelView software on a Silicone Graphics workstation and rotated. All samples contained neurons with duplicated apical dendrites, additional basal dendrites or were misplaced in a horizontal position in the white matter. The relation between these preliminary observations and the disease is discussed. PMID:1421134

  10. Pyramidal texturing of silicon solar cell with TMAH chemical anisotropic etching

    Energy Technology Data Exchange (ETDEWEB)

    Papet, P.; Nichiporuk, O.; Kaminski, A.; Rozier, Y.; Kraiem, J.; Lelievre, J.-F.; Chaumartin, A.; Fave, A.; Lemiti, M. [Laboratoire de Physique de la Matiere, UMR-CNRS 5511, Institut National des Sciences Appliquees de Lyon, Bat Blaise Pascal, 7 avenue Jean Capelle, 69621 Villeurbanne Cedex (France)

    2006-09-22

    High-efficiency silicon solar cells need a textured front surface to reduce reflectance and to improve light trapping. Texturing of monocrystalline silicon is usually done in alkaline solutions. These solutions are cheaper, but are pollutants of silicon technologies. In this paper, we investigate an alternative solution containing tetramethyl ammonium hydroxide ((CH{sub 3}){sub 4}NOH, TMAH ). This study shows the influence of different parameters (concentration, agitation, duration and temperature), to obtain uniform and reliable pyramidal texturization on different silicon surfaces (as cut, etched and polished). Under optimized conditions, TMAH-textured surface led to an average weighted reflectance of 13%, without any antireflection coating independent of the initial silicon surface. Unlike potassium hydroxide (KOH) texturing solution, characterization of silicon oxide layer contamination after TMAH texturing process revealed no pollution, and passivation is less affected by TMAH than by KOH texturization. (author)

  11. Exogenous progesterone exacerbates running response of adolescent female mice to repeated food restriction stress by changing α4-GABAA receptor activity of hippocampal pyramidal cells.

    Science.gov (United States)

    Wable, G S; Chen, Y-W; Rashid, S; Aoki, C

    2015-12-01

    Adolescent females are particularly vulnerable to mental illnesses with co-morbidity of anxiety, such as anorexia nervosa (AN). We used an animal model of AN, called activity-based anorexia (ABA), to investigate the neurobiological basis of vulnerability to repeated, food restriction (FR) stress-evoked anxiety. Twenty-one of 23 adolescent female mice responded to the 1st FR with increased wheel-running activity (WRA), even during the limited period of food access, thereby capturing AN's symptoms of voluntary FR and over-exercise. Baseline WRA was an excellent predictor of FR-elicited WRA (severity of ABA, SOA), with high baseline runners responding to FR with minimal SOA (i.e., negative correlation). Nine gained resistance to ABA following the 1st FR. Even though allopregnanolone (3α-OH-5α-pregnan-20-one, THP), the metabolite of progesterone (P4), is a well-recognized anxiolytic agent, subcutaneous P4 to these ABA-resistant animals during the 2nd FR was exacerbative, evoking greater WRA than the counterpart resistant group that received oil vehicle, only. Moreover, P4 had no WRA-reducing effect on animals that remained ABA-vulnerable. To explain the sensitizing effect of P4 upon the resistant mice, we examined the relationship between P4 treatment and levels of the α4 subunit of GABAARs at spines of pyramidal cells of the hippocampal CA1, a parameter previously shown to correlate with resistance to ABA. α4 levels at spine membrane correlated strongly and negatively with SOA during the 1st ABA (prior to P4 injection), confirming previous findings. α4 levels were greater among P4-treated animals that had gained resistance than of vehicle-treated resistant animals or of the vulnerable animals with or without P4. We propose that α4-GABAARs play a protective role by counterbalancing the ABA-induced increase in excitability of CA1 pyramidal neurons, and although exogenous P4's metabolite, THP, enhances α4 expression, especially among those that can gain resistance

  12. Roller Coaster Scanning reveals spontaneous triggering of dendritic spikes in CA1 interneurons.

    Science.gov (United States)

    Katona, Gergely; Kaszás, Attila; Turi, Gergely F; Hájos, Norbert; Tamás, Gábor; Vizi, E Sylvester; Rózsa, Balázs

    2011-02-01

    Inhibitory interneurons are considered to be the controlling units of neural networks, despite their sparse number and unique morphological characteristics compared with excitatory pyramidal cells. Although pyramidal cell dendrites have been shown to display local regenerative events--dendritic spikes (dSpikes)--evoked by artificially patterned stimulation of synaptic inputs, no such studies exist for interneurons or for spontaneous events. In addition, imaging techniques have yet to attain the required spatial and temporal resolution for the detection of spontaneously occurring events that trigger dSpikes. Here we describe a high-resolution 3D two-photon laser scanning method (Roller Coaster Scanning) capable of imaging long dendritic segments resolving individual spines and inputs with a temporal resolution of a few milliseconds. By using this technique, we found that local, NMDA receptor-dependent dSpikes can be observed in hippocampal CA1 stratum radiatum interneurons during spontaneous network activities in vitro. These NMDA spikes appear when approximately 10 spatially clustered inputs arrive synchronously and trigger supralinear integration in dynamic interaction zones. In contrast to the one-to-one relationship between computational subunits and dendritic branches described in pyramidal cells, here we show that interneurons have relatively small (∼14 μm) sliding interaction zones. Our data suggest a unique principle as to how interneurons integrate synaptic information by local dSpikes. PMID:21224413

  13. Models of neocortical layer 5b pyramidal cells capturing a wide range of dendritic and perisomatic active properties.

    Directory of Open Access Journals (Sweden)

    Etay Hay

    2011-07-01

    Full Text Available The thick-tufted layer 5b pyramidal cell extends its dendritic tree to all six layers of the mammalian neocortex and serves as a major building block for the cortical column. L5b pyramidal cells have been the subject of extensive experimental and modeling studies, yet conductance-based models of these cells that faithfully reproduce both their perisomatic Na(+-spiking behavior as well as key dendritic active properties, including Ca(2+ spikes and back-propagating action potentials, are still lacking. Based on a large body of experimental recordings from both the soma and dendrites of L5b pyramidal cells in adult rats, we characterized key features of the somatic and dendritic firing and quantified their statistics. We used these features to constrain the density of a set of ion channels over the soma and dendritic surface via multi-objective optimization with an evolutionary algorithm, thus generating a set of detailed conductance-based models that faithfully replicate the back-propagating action potential activated Ca(2+ spike firing and the perisomatic firing response to current steps, as well as the experimental variability of the properties. Furthermore, we show a useful way to analyze model parameters with our sets of models, which enabled us to identify some of the mechanisms responsible for the dynamic properties of L5b pyramidal cells as well as mechanisms that are sensitive to morphological changes. This automated framework can be used to develop a database of faithful models for other neuron types. The models we present provide several experimentally-testable predictions and can serve as a powerful tool for theoretical investigations of the contribution of single-cell dynamics to network activity and its computational capabilities.

  14. Using the MCF10A/MCF10CA1a Breast Cancer Progression Cell Line Model to Investigate the Effect of Active, Mutant Forms of EGFR in Breast Cancer Development and Treatment Using Gefitinib.

    Directory of Open Access Journals (Sweden)

    Darrell C Bessette

    Full Text Available Basal-like and triple negative breast cancer (TNBC share common molecular features, poor prognosis and a propensity for metastasis to the brain. Amplification of epidermal growth factor receptor (EGFR occurs in ~50% of basal-like breast cancer, and mutations in the epidermal growth factor receptor (EGFR have been reported in up to ~ 10% of Asian TNBC patients. In non-small cell lung cancer several different mutations in the EGFR tyrosine kinase domain confer sensitivity to receptor tyrosine kinase inhibitors, but the tumourigenic potential of EGFR mutations in breast cells and their potential for targeted therapy is unknown.Constructs containing wild type, G719S or E746-A750 deletion mutant forms of EGFR were transfected into the MCF10A breast cells and their tumorigenic derivative, MCF10CA1a. The effects of EGFR over-expression and mutation on proliferation, migration, invasion, response to gefitinib, and tumour formation in vivo was investigated. Copy number analysis and whole exome sequencing of the MCF10A and MCF10CA1a cell lines were also performed.Mutant EGFR increased MCF10A and MCF10CA1a proliferation and MCF10A gefitinib sensitivity. The EGFR-E746-A750 deletion increased MCF10CA1a cell migration and invasion, and greatly increased MCF10CA1a xenograft tumour formation and growth. Compared to MCF10A cells, MCF10CA1a cells exhibited large regions of gain on chromosomes 3 and 9, deletion on chromosome 7, and mutations in many genes implicated in cancer.Mutant EGFR enhances the oncogenic properties of MCF10A cell line, and increases sensitivity to gefitinib. Although the addition of EGFR E746-A750 renders the MCF10CA1a cells more tumourigenic in vivo it is not accompanied by increased gefitinib sensitivity, perhaps due to additional mutations, including the PIK3CA H1047R mutation, that the MCF10CA1a cell line has acquired. Screening TNBC/basal-like breast cancer for EGFR mutations may prove useful for directing therapy but, as in non

  15. A Simulation Study on the Effects of Dendritic Morphology on Layer V Prefontal Pyramidal Cell Firing Behavior

    Directory of Open Access Journals (Sweden)

    Maria ePsarrou

    2014-09-01

    Full Text Available Pyramidal cells, the most abundant neurons in neocortex, exhibit significant structural variability across different brain areas and layers in different species. Moreover, in response to a somatic step current, these cells display a range of firing behaviors, the most common being (1 repetitive action potentials (Regular Spiking - RS, and (2 an initial cluster of 2-5 action potentials with short ISIs followed by single spikes (Intrinsic Bursting - IB. A correlation between firing behavior and dendritic morphology has recently been reported. In this work we use computational modeling to investigate quantitatively the effects of the basal dendritic tree morphology on the firing behavior of 112 three-dimensional reconstructions of layer V PFC rat pyramidal cells. Particularly, we focus on how different morphological (diameter, total length, volume and branch number and passive (Mean Electrotonic Path length features of basal dendritic trees shape somatic firing when the spatial distribution of ionic mechanisms in the basal dendritic trees is uniform or non-uniform. Our results suggest that total length, volume and branch number are the best morphological parameters to discriminate the cells as RS or IB, regardless of the distribution of ionic mechanisms in basal trees. The discriminatory power of total length, volume and branch number remains high in the presence of different apical dendrites. These results suggest that morphological variations in the basal dendritic trees of layer V pyramidal neurons in the PFC influence their firing patterns in a predictive manner and may in turn influence the information processing capabilities of these neurons.

  16. The influence of the opening between the heads of the two closest pyramids in textured surface for solar cells and its application on the spectral response

    International Nuclear Information System (INIS)

    This study is concerned with the development of a new solar cell prototype in order to improve photovoltaic efficiency. In this model we show that the material can have five and more successive incident-ray absorptions instead of three current, where we changed the direction of the reflected ray, by varying the angle between the two neighbouring pyramids, the incidence angle, the opening between the heads of the two closest pyramids and their height. Thus, with an angle between the two neighbouring pyramids varying between 24 and 12° and an angle of incidence varying between 78 and 84°, the opening between the heads of the two closest pyramids varied respectively from 4.25 to 2.10 μm for a pyramid height of 10 μm. This leads to a substantial increase of the spectral response and the photovoltaic efficiency.

  17. Dopamine D3 receptors inhibit hippocampal gamma oscillations by disturbing CA3 pyramidal cell firing synchrony

    Directory of Open Access Journals (Sweden)

    Clément E. Lemercier

    2016-01-01

    Full Text Available Cortical gamma oscillations are associated with cognitive processes and are altered in several neuropsychiatric conditions such as schizophrenia and Alzheimer’s disease. Since dopamine D3 receptors are possible targets in treatment of these conditions, it is of great importance to understand their role in modulation of gamma oscillations. The effect of D3 receptors on gamma oscillations and the underlying cellular mechanisms were investigated by extracellular local field potential and simultaneous intracellular sharp micro-electrode recordings in the CA3 region of the hippocampus in vitro. D3 receptors decreased the power and broadened the bandwidth of gamma oscillations induced by acetylcholine or kainate. Blockade of the D3 receptors resulted in faster synchronization of the oscillations, suggesting that endogenous dopamine in the hippocampus slows down the dynamics of gamma oscillations by activation of D3 receptors. Investigating the underlying cellular mechanisms for these effects showed that D3 receptor activation decreased the rate of action potentials during gamma oscillations and reduced the precision of the action potential phase coupling to the gamma cycle in CA3 pyramidal cells. The results may offer an explanation how selective activation of D3 receptors may impair cognition and how, in converse, D3 antagonists may exert pro-cognitive and antipsychotic effects.

  18. Dopamine D3 Receptors Inhibit Hippocampal Gamma Oscillations by Disturbing CA3 Pyramidal Cell Firing Synchrony.

    Science.gov (United States)

    Lemercier, Clément E; Schulz, Steffen B; Heidmann, Karin E; Kovács, Richard; Gerevich, Zoltan

    2015-01-01

    Cortical gamma oscillations are associated with cognitive processes and are altered in several neuropsychiatric conditions such as schizophrenia and Alzheimer's disease. Since dopamine D3 receptors are possible targets in treatment of these conditions, it is of great importance to understand their role in modulation of gamma oscillations. The effect of D3 receptors on gamma oscillations and the underlying cellular mechanisms were investigated by extracellular local field potential and simultaneous intracellular sharp micro-electrode recordings in the CA3 region of the hippocampus in vitro. D3 receptors decreased the power and broadened the bandwidth of gamma oscillations induced by acetylcholine or kainate. Blockade of the D3 receptors resulted in faster synchronization of the oscillations, suggesting that endogenous dopamine in the hippocampus slows down the dynamics of gamma oscillations by activation of D3 receptors. Investigating the underlying cellular mechanisms for these effects showed that D3 receptor activation decreased the rate of action potentials (APs) during gamma oscillations and reduced the precision of the AP phase coupling to the gamma cycle in CA3 pyramidal cells. The results may offer an explanation how selective activation of D3 receptors may impair cognition and how, in converse, D3 antagonists may exert pro-cognitive and antipsychotic effects. PMID:26779018

  19. Pattern and inhibition-dependent invasion of pyramidal cell dendrites by fast spikes in the hippocampus in vivo.

    OpenAIRE

    Buzsáki, G.; Penttonen, M; Nádasdy, Z; Bragin, A.

    1996-01-01

    The invasion of sodium spikes from the soma into dendrites was studied in hippocampal pyramidal cells by simultaneous extracellular and intracellular recordings in anesthetized rats and by simultaneous extracellular recordings of the somatic and dendritic potentials in freely behaving animals. During complex-spike patterns, recorded in the immobile or sleeping animal, dendritic invasion of successive spikes was substantially attenuated. Complex-spike bursts occurred in association with popula...

  20. Postnatal development of layer III pyramidal cells in the primary visual, inferior temporal, and prefrontal cortices of the marmoset

    OpenAIRE

    Hirosato eAoi; Tomofumi eOga; Tetsuya eSasaki; Ichiro eFujita; Noritaka eIchinohe

    2013-01-01

    Abnormalities in the processes of the generation and/or pruning of dendritic spines have been implicated in several mental disorders including autism and schizophrenia. We have chosen to examine the common marmoset (Callithrix jacchus) as a primate model to explore the processes. As a first step, we studied the postnatal development of basal dendritic trees and spines of layer-III pyramidal cells in the primary visual sensory cortex (V1), a visual association cortex (inferior temporal area, T...

  1. Chandelier cells control excessive cortical excitation: characteristics of whisker-evoked synaptic responses of layer 2/3 nonpyramidal and pyramidal neurons.

    Science.gov (United States)

    Zhu, Yinghua; Stornetta, Ruth L; Zhu, J Julius

    2004-06-01

    Chandelier cells form inhibitory axo-axonic synapses on pyramidal neurons with their characteristic candlestick-like axonal terminals. The functional role of chandelier cells is still unclear, although the preferential loss of this cell type at epileptic loci suggests a role in epilepsy. Here we report an examination of whisker- and spontaneous activity-evoked responses in chandelier cells and other fast-spiking nonpyramidal neurons and regular-spiking pyramidal neurons in layer 2/3 of the barrel cortex. Fast-spiking nonpyramidal neurons, including chandelier cells, basket cells, neurogliaform cells, double bouquet cells, net basket cells, bitufted cells, and regular-spiking pyramidal neurons all respond to stimulation of multiple whiskers on the contralateral face. Whisker stimulation, however, evokes small, delayed EPSPs preceded by an earlier IPSP and no action potentials in chandelier cells, different from other nonpyramidal and pyramidal neurons. In addition, chandelier cells display a larger receptive field with lower acuity than other fast-spiking nonpyramidal neurons and pyramidal neurons. Notably, simultaneous dual whole-cell in vivo recordings show that chandelier cells, which rarely fire action potentials spontaneously, fire more robustly than other types of cortical neurons when the overall cortical excitation increases. Thus, chandelier cells may not process fast ascending sensory information but instead may be reserved to prevent excessive excitatory activity in neuronal networks. PMID:15175379

  2. Mu opioid receptor up-regulation and participation in excitability of hippocampal pyramidal cell electrophysiology

    International Nuclear Information System (INIS)

    Chronic administration of opiate antagonists to rats results in up-regulation of their brain opioid receptors. Using subcellular fractionation techniques, brain opioid receptors were resolved into two membrane populations, one associated with synaptic plasma membranes (SPM) and the other enriched in smooth endoplasmic reticulum and Golgi (microsomes). This study addressed in part the question of whether an antagonist induces up-regulation uniformly in these two populations. Rats were administered naltrexone by subcutaneously implanted osmotic minipumps. Forebrain mu receptor levels were determined by homologous displacement of (3H)D-ala2-mePhe4-gly-ol5-enkephalin (DAGO) followed by computer estimation of binding parameters. Receptor levels in crude membranes rose 77% after treatment. Microsomes displayed a 92% increase, a two-fold greater change than in SPMs (51%). These results establish that naltrexone induces up-regulation of both membrane populations; and that microsomal and SPM receptors represent discrete populations of intracellular and cell surface sites, respectively. Binding experiments on isolated hippocampi also demonstrated up-regulation (71%) of mu receptors. To demonstrate up-regulation of opioid receptors electrophysiologically, hippocampal slices were prepared from rats which had been chronically treated with naltrexone. After superfusion with DAGO, these slices showed a 42% greater population spike output than controls in response to the same EPSP input. Hippocampi from animals treated for two weeks showed an additional increase in sensitivity. The results support a disinhibitory role for opioids in pyramidal cell hyper-excitability. More importantly, they demonstrate a significant physiological correlate to opioid receptor up-regulation

  3. Hippocampal CA1/subiculum-prefrontal cortical pathways induce plastic changes of nociceptive responses in cingulate and prelimbic areas

    Directory of Open Access Journals (Sweden)

    Nakamura Hiroyuki

    2010-08-01

    Full Text Available Abstract Background Projections from hippocampal CA1-subiculum (CA1/SB areas to the prefrontal cortex (PFC, which are involved in memory and learning processes, produce long term synaptic plasticity in PFC neurons. We examined modifying effects of these projections on nociceptive responses recorded in the prelimbic and cingulate areas of the PFC. Results Extracellular unit discharges evoked by mechanical noxious stimulation delivered to the rat-tail and field potentials evoked by a single stimulus pulse delivered to CA1/SB were recorded in the PFC. High frequency stimulation (HFS, 100 Hz delivered to CA1/SB, which produced long-term potentiation (LTP of field potentials, induced long-term enhancement (LTE of nociceptive responses in 78% of cases, while, conversely, in 22% responses decreased (long-term depression, LTD. These neurons were scattered throughout the cingulate and prelimbic areas. The results obtained for field potentials and nociceptive discharges suggest that CA1/SB-PFC pathways can produce heterosynaptic potentiation in PFC neurons. HFS had no effects on Fos expression in the cingulated cortex. Low frequency stimulation (LFS, 1 Hz, 600 bursts delivered to the CA1/SB induced LTD of nociceptive discharges in all cases. After recovery from LTD, HFS delivered to CA1/SB had the opposite effect, inducing LTE of nociceptive responses in the same neuron. The bidirectional type of plasticity was evident in these nociceptive responses, as in the homosynaptic plasticity reported previously. Neurons inducing LTD are found mainly in the prelimbic area, in which Fos expression was also shown to be inhibited by LFS. The electrophysiological results closely paralleled those of immunostaining. Our results indicate that CA1/SB-PFC pathways inhibit excitatory pyramidal cell activities in prelimbic areas. Conclusion Pressure stimulation (300 g applied to the rat-tail induced nociceptive responses in the cingulate and prelimbic areas of the PFC, which

  4. Mnemonic Functions for Nonlinear Dendritic Integration in Hippocampal Pyramidal Circuits.

    Science.gov (United States)

    Kaifosh, Patrick; Losonczy, Attila

    2016-05-01

    We present a model for neural circuit mechanisms underlying hippocampal memory. Central to this model are nonlinear interactions between anatomically and functionally segregated inputs onto dendrites of pyramidal cells in hippocampal areas CA3 and CA1. We study the consequences of such interactions using model neurons in which somatic burst-firing and synaptic plasticity are controlled by conjunctive processing of these separately integrated input pathways. We find that nonlinear dendritic input processing enhances the model's capacity to store and retrieve large numbers of similar memories. During memory encoding, CA3 stores heavily decorrelated engrams to prevent interference between similar memories, while CA1 pairs these engrams with information-rich memory representations that will later provide meaningful output signals during memory recall. While maintaining mathematical tractability, this model brings theoretical study of memory operations closer to the hippocampal circuit's anatomical and physiological properties, thus providing a framework for future experimental and theoretical study of hippocampal function. PMID:27146266

  5. Augmented inhibition from cannabinoid sensitive interneurons diminishes CA1 output after traumatic brain injury

    Directory of Open Access Journals (Sweden)

    Brian Neal Johnson

    2014-12-01

    Full Text Available The neurological impairments associated with traumatic brain injury include learning and memory deficits and increased risk of seizures. The hippocampus is critically involved in both of these phenomena and highly susceptible to damage by traumatic brain injury. To examine network activity in the hippocampal CA1 region after lateral fluid percussion injury, we used a combination of voltage sensitive dye, field potential and patch clamp recording in mouse hippocampal brain slices. When the stratum radiatum was stimulated in slices from injured mice we found decreased depolarization in stratum radiatum and increased hyperpolarization in stratum oriens, together with a decrease in the percentage of pyramidal neurons firing stimulus-evoked action potentials. Increased hyperpolarization in stratum oriens persisted when glutamatergic transmission was blocked. However, we found no changes in stratum oriens responses when the alveus was stimulated to directly activate stratum oriens. These results suggest that the increased stratum oriens hyperpolarization evoked by stratum radiatum stimulation was mediated by interneurons that have cell bodies and/or axons in stratum radiatum, and form synapses in stratum pyramidale and stratum oriens. A low concentration (100 nM of the synthetic cannabinoid WIN55,212-2,restored CA1 output in slices from injured animals. These findings support the hypothesis that increased GABAergic signaling by cannabinoid sensitive interneurons contributes to the reduced CA1 output following traumatic brain injury.

  6. Neuroprotective effect of olive oil in the hippocampus CA1 neurons following ischemia: Reperfusion in mice

    Directory of Open Access Journals (Sweden)

    M Zamani

    2013-01-01

    Full Text Available Introduction: Transient global ischemia induces selective, delayed neuronal death of pyramidal neurons in the hippocampal CA1. Oxidative Stress is considered to be involved in a number of human diseases including ischemia. Preliminary studies confirmed reduction of cell death in brain following treatment with antioxidants. Aim: According to this finding, we study the relationship between consumption of olive oil on cell death and memory disorder in brain ischemia. We studied the protective effect of olive oil against ischemia-reperfusion. Material and Methods: Experimental design includes three groups: Intact (n = 8, ischemic control (n = 8 and treatment groups with olive oil (n = 8. The mice treated with olive oil as pre-treatment for a week. Then, ischemia induced by common carotid artery ligation and following the reduction of inflammation [a week after ischemia], the mice post-treated with olive oil. Nissl staining applied for counting necrotic cells in hippocampus CA1. Tunnel kit was used to quantify apoptotic cell death while to short term memory scale, we apply y-maze and shuttle box tests and for detection the rate of apoptotic and treated cell, we used western blotting test for bax and bcl2 proteins. Results: High rate of apoptosis was seen in ischemic group that significantly associated with short-term memory loss. Cell death was significantly lower when mice treated with olive oil. The memory test results were adjusted with cell death results and bax and bcl2 expression in all groups′ comparison. Ischemia for 15 min induced cell death in hippocampus with more potent effect on CA1. Conclusion: Olive oil intake significantly reduced cell death and decreased memory loss.

  7. Long-term depression is differentially expressed in distinct lamina of hippocampal CA1 dendrites

    Directory of Open Access Journals (Sweden)

    Binu eRamachandran

    2015-02-01

    Full Text Available Information storage in CA1 hippocampal pyramidal neurons is compartmentalized in proximal versus distal apical dendrites, cell bodies, and basal dendrites. This compartmentalization is thought to be essential for synaptic integration. Differences in the expression of LTP in each of these compartments have been described, but less is known regarding potential differences in LTD. Here, to directly compare LTD expression in each compartment and to bypass possible differences in input-specificity and stimulation of presynaptic inputs, we used global application of NMDA to induce LTD. We then examined LTD expression in each dendritic sub-region - proximal and distal apical, and basal dendrites - and in cell bodies. Interestingly, we found that distal apical dendrites exhibited the greatest magnitude of LTD of all areas tested and this LTD was maintained, whereas LTD in proximal apical dendrites was not maintained. In basal dendrites, LTD was also maintained, but the magnitude of LTD was less than in distal apical dendrites. Blockade of inhibition blocked LTD maintenance in both distal apical and basal dendrites. Population spikes recorded from the cell body layer correlated with apical dendrite fEPSPs, where LTD was maintained in distal dendrites and decayed in proximal dendrites. On the other hand, LTD of basal dendrite fEPSPs was maintained but population spike responses were not. Thus E-S coupling was distinct in basal and apical dendrites. Our data demonstrate cell autonomous differential information processing in somas and dendritic sub-regions of CA1 pyramidal neurons in the hippocampus, where LTD expression is intrinsic to distinct dendritic regions, and does not depend on the nature of stimulation and input specificity.

  8. Ischemia-induced neural stem/progenitor cells express pyramidal cell markers

    NARCIS (Netherlands)

    Clausen, Martijn; Nakagomi, Takayuki; Nakano-Doi, Akiko; Saino, Orie; Takata, Masashi; Taguchi, Akihiko; Luiten, Paul; Matsuyama, Tomohiro

    2011-01-01

    Adult brain-derived neural stem cells have acquired a lot of interest as an endurable neuronal cell source that can be used for central nervous system repair in a wide range of neurological disorders such as ischemic stroke. Recently, we identified injury-induced neural stem/progenitor cells in the

  9. Changes in synaptic plasticity and expression of glutamate receptor subunits in the CA1 and CA3 areas of the hippocampus after transient global ischemia.

    Science.gov (United States)

    Han, Xin-Jia; Shi, Zhong-Shan; Xia, Luo-Xing; Zhu, Li-Hui; Zeng, Ling; Nie, Jun-Hua; Xu, Zao-Cheng; Ruan, Yi-Wen

    2016-07-01

    Excess glutamate release from the presynaptic membrane has been thought to be the major cause of ischemic neuronal death. Although both CA1 and CA3 pyramidal neurons receive presynaptic glutamate input, transient cerebral ischemia induces CA1 neurons to die while CA3 neurons remain relatively intact. This suggests that changes in the properties of pyramidal cells may be the main cause related to ischemic neuronal death. Our previous studies have shown that the densities of dendritic spines and asymmetric synapses in the CA1 area are increased at 12h and 24h after ischemia. In the present study, we investigated changes in synaptic structures in the CA3 area and compared the expression of glutamate receptors in the CA1 and CA3 hippocampal regions of rats after ischemia. Our results demonstrated that the NR2B/NR2A ratio became larger after ischemia although the expression of both the NR2B subunit (activation of apoptotic pathway) and NR2A subunit (activation of survival pathway) decreased in the CA1 area from 6h to 48h after reperfusion. Furthermore, expression of the GluR2 subunit (calcium impermeable) of the AMPA receptor class significantly decreased while the GluR1 subunit (calcium permeable) remained unchanged at the same examined reperfusion times, which subsequently caused an increase in the GluR1/GluR2 ratio. Despite these notable differences in subunit expression, there were no obvious changes in the density of synapses or expression of NMDAR and AMPAR subunits in the CA3 area after ischemia. These results suggest that delayed CA1 neuronal death may be related to the dramatic fluctuation in the synaptic structure and relative upregulation of NR2B and GluR1 subunits induced by transient global ischemia. PMID:27090818

  10. Entorhinal theta-frequency input to the dentate gyrus trisynaptically evokes hippocampal CA1 LTP

    Directory of Open Access Journals (Sweden)

    Jens eStepan

    2012-09-01

    Full Text Available There exists substantial evidence that some forms of explicit learning in mammals require long-term potentiation (LTP at hippocampal CA3-CA1 synapses. While CA1 LTP has been well characterized at the monosynaptic level, it still remains unclear how the afferent systems to the hippocampus can initiate formation of this neuroplastic phenomenon. Using voltage-sensitive dye imaging in a mouse brain slice preparation, we show that evoked entorhinal cortical (EC theta-frequency input to the dentate gyrus highly effectively generates waves of neuronal activity which propagate through the entire trisynaptic circuit of the hippocampus (‘HTC-Waves’. This flow of activity, which we also demonstrate in vivo, critically depends on frequency facilitation of mossy fiber to CA3 synaptic transmission. The HTC-Waves are rapidly boosted by the cognitive enhancer caffeine (5 µM and the stress hormone corticosterone (100 nM. They precisely follow the rhythm of the EC input, involve high-frequency firing (>100 Hz of CA3 pyramidal neurons, and induce NMDA receptor-dependent CA1 LTP within a few seconds. Our study provides the first experimental evidence that synchronous theta-rhythmical spiking of EC stellate cells, as occurring during EC theta oscillations, has the capacity to drive induction of CA1 LTP via the hippocampal trisynaptic pathway. Moreover, we present data pointing to a basic filter mechanism of the hippocampus regarding EC inputs and describe a methodology to reveal alterations in the ‘input-output relationship’ of the hippocampal trisynaptic circuit.

  11. Activity-mediated plasticity of GABA equilibrium potential in rat hippocampal CA1 neurons.

    Science.gov (United States)

    Yang, B; Tadavarty, R; Xu, J-Y; Sastry, B R

    2010-01-01

    The equilibrium potential (E(GABA)(-PSC)) for gamma-aminobutyric acid (GABA) A receptor mediated inhibitory postsynaptic currents (PSCs) in hippocampal CA1 pyramidal neurons shifts when theta-burst stimulation (four pulses at 100 Hz in each burst in a train consisting of five bursts with an inter-burst interval of 200 ms, the train repeated thrice at 30-s intervals) is applied to the input. E(GABA)(-PSC) is regulated by K(+)/Cl(-) co-transporter (KCC2). GABA(B) receptors are implicated in modulating KCC2 levels. In the current study, the involvement of KCC2, as well as GABA(B) receptors, in theta-burst-mediated shifts in E(GABA)(-PSC) was examined. Whole-cell patch recordings were made from hippocampal CA1 pyramidal neurons (from 9 to 12 days old rats), in a slice preparation. Glutamatergic excitatory postsynaptic currents were blocked with dl-2-amino-5-phosphonovaleric acid (50 microM) and 6,7-dinitroquinoxaline-2,3-dione (20 microM). The PSC and the E(GABA)(-PSC) were stable when stimulated at 0.05 Hz. However, both changed following a 30-min stimulation at 0.5 or 1 Hz. Furosemide (500 microM) and KCC2 anti-sense in the recording pipette but not bumetanide (20 or 100 microM) or KCC2 sense, blocked the changes, suggesting KCC2 involvement. Theta-burst stimulation induced a negative shift in E(GABA)(-PSC), which was prevented by KCC2 anti-sense; however, KCC2 sense had no effect. CGP55845 (2 microM), a GABA(B) antagonist, applied in the superfusing medium, or GDP-beta-S in the recording pipette, blocked the shift in E(GABA)(-PSC). These results indicate that activity-mediated plasticity in E(GABA)(-PSC) occurs in hippocampal CA1 pyramidal neurons and theta-burst-induced negative shift in E(GABA)(-PSC) requires KCC2, GABA(B) receptors and G-protein activation. PMID:19879261

  12. Automatic Classification of Human Epithelial Type 2 Cell Indirect Immunofluorescence Images using Cell Pyramid Matching

    OpenAIRE

    Wiliem, Arnold; Sanderson, Conrad; Wong, Yongkang; Hobson, Peter; Minchin, Rodney F.; Lovell, Brian C.

    2014-01-01

    This paper describes a novel system for automatic classification of images obtained from Anti-Nuclear Antibody (ANA) pathology tests on Human Epithelial type 2 (HEp-2) cells using the Indirect Immunofluorescence (IIF) protocol. The IIF protocol on HEp-2 cells has been the hallmark method to identify the presence of ANAs, due to its high sensitivity and the large range of antigens that can be detected. However, it suffers from numerous shortcomings, such as being subjective as well as time and...

  13. The influence of the opening between the heads of the two closest pyramids in textured surface for solar cells and its application on the spectral response

    Science.gov (United States)

    Hamel, A.

    2014-05-01

    The work presented in this study is concerned the development of a new solar cell prototype in order to improve photovoltaic efficiency In this model we show that the material can have five and more successive incident ray absorptions instead of three currently, where we changed the direction of the reflected ray, by varying the angle between the two neighbouring pyramids, the incidence angle, the opening between the heads of the two closest pyramids and their height. Thus, with an angle between the two neighbouring pyramid varying between 24° and 12° and for angle of incidence varying between 78° and 84°. For these values of the angle between the two neighbouring pyramids and incidence angle, the opening between the heads of the two closest pyramids varied respectively from 4.25 to 2.10 μm for a pyramid height of 10 μm. This lead to a substantial increase of the spectral response and the photovoltaic efficiency.

  14. Lovastatin reduces neuronal cell death in hippocampal CA1 subfield after pilocarpine-induced status epilepticus: preliminary results Lovastatina reduz a lesão celular na região CA1 do hipocampo após o status epilepticus induzido pela pilocarpina: resultados preliminares

    Directory of Open Access Journals (Sweden)

    Pauline Rangel

    2005-12-01

    Full Text Available OBJECTIVE: To further characterize the capacity of lovastatin to prevent hippocampal neuronal loss after pilocarpine-induced status epilepticus (SE METHOD: Adult male Wistar rats were divided into four groups: (A control rats, received neither pilocarpine nor lovastatin (n=5; (B control rats, received just lovastatin (n=5; (C rats that received just pilocarpine (n=5; (D rats that received pilocarpine and lovastatin (n=5. After pilocarpine injection (350mg/kg, i.p., only rats that displayed continuous, convulsive seizure activity were included in our study. Seizure activity was monitored behaviorally and terminated with an injection of diazepam (10 mg/kg, i.p. after 4 h of convulsive SE. The rats treated with lovastatin received two doses of 20mg/kg via an oesophagic probe immediately and 24 hours after SE induction. Seven days after pilocarpine-induced SE, all the animals were perfused and their brains were processed for histological analysis through Nissl method. RESULTS: The cell counts in the Nissl-stained sections performed within the hippocampal formation showed a significant cell loss in rats that received pilocarpine and presented SE (CA1= 26.8 ± 13.67; CA3= 38.1 ± 7.2; hilus= 43.8 ± 3.95 when compared with control group animals (Group A: CA1= 53.2 ± 9.63; CA3= 63.5 ± 13.35; hilus= 59.08 ± 10.24; Group B: CA1= 74.3 ± 8.16; CA3= 70.1 ± 3.83; hilus= 70.6 ± 5.10. The average neuronal cell number of CA1 subfield of rats that present SE and received lovastatin (44.4 ± 17.88 was statically significant increased when compared with animals that just presented SE. CONCLUSION: Lovastatin exert a neuroprotective role in the attenuation of brain damage after SE.OBJETIVO: Capacidade da lovastatina em prevenir a perda de neurônios hipocampais após o status epilepticus (SE induzido pela pilocarpina. MÉTODO: Ratos adultos Wistar foram divididos em 4 grupos: (A ratos controles que não receberam pilocarpina nem lovastatina (n=5; (B ratos

  15. Functional Optical Probing of the Hippocampal Trisynaptic Circuit In Vitro: Network Dynamics, Filter Properties, and Polysynaptic Induction of CA1 LTP

    Directory of Open Access Journals (Sweden)

    Jens eStepan

    2015-05-01

    Full Text Available Decades of brain research have identified various parallel loops linking the hippocampus with neocortical areas, enabling the acquisition of spatial and episodic memories. Especially the hippocampal trisynaptic circuit (entorhinal cortex layer II  dentate gyrus (DG  cornu ammonis (CA-3  CA1 was studied in great detail because of its seemingly simple connectivity and characteristic structures that are experimentally well accessible. While numerous researchers focused on functional aspects, obtained from a limited number of cells in distinct hippocampal subregions, little is known about the neuronal network dynamics which drive information across multiple synapses for subsequent long-term storage. Fast voltage-sensitive dye imaging in vitro allows real-time recording of activity patterns in large/meso-scale neuronal networks with high spatial resolution. In this way, we recently found that entorhinal theta-frequency input to the DG most effectively passes filter mechanisms of the trisynaptic circuit network, generating activity waves which propagate across the entire DG-CA axis. These trisynaptic circuit waves involve high-frequency firing of CA3 pyramidal neurons, leading to a rapid induction of classical NMDA receptor-dependent long-term potentiation (LTP at CA3-CA1 synapses (CA1 LTP. CA1 LTP has been substantially evidenced to be essential for some forms of explicit learning in mammals. Here, we review data with particular reference to whole network-level approaches, illustrating how activity propagation can take place within the trisynaptic circuit to drive formation of CA1 LTP.

  16. Clustering of population pyramids

    OpenAIRE

    Kejžar, Nataša; Korenjak-Černe, Simona; Batagelj, Vladimir

    2015-01-01

    Population pyramid is a very popular presentation of the age-sex distribution of the human population of a particular region. The shape of the pyramid shows many demographic, social, and political characteristics of the time and the region. In the paper results of hierarchical clustering of the world countries based on population pyramids are presented. Special attention is given to the shapes of the pyramids. The changes of the pyramids' shapes, and also changes of the countries inside main ...

  17. Clustering of population pyramids:

    OpenAIRE

    Batagelj, Vladimir; Kejžar, Nataša; Korenjak-Černe, Simona

    2008-01-01

    Population pyramid is a very popular presentation of the age-sex distribution of the human population of a particular region. The shape of the pyramid shows many demographic, social, and political characteristics of the time and the region. In the paper results of hierarchical clustering of the world countries based on population pyramids are presented. Special attention is given to the shapes of the pyramids. The changes of the pyramids' shapes, and also changes of the countries inside main ...

  18. Melamine Alters Glutamatergic Synaptic Transmission of CA3-CA1 Synapses Presynaptically Through Autophagy Activation in the Rat Hippocampus.

    Science.gov (United States)

    Zhang, Hui; Wang, Hui; Xiao, Xi; Zhang, Tao

    2016-01-01

    Melamine is an industrial chemical that can cause central nervous system disorders including excitotoxicity and cognitive impairment. Its illegal use in powdered baby formula was the focus of a milk scandal in China in 2008. One of our previous studies showed that melamine impaired glutamatergic transmission in rat hippocampal CA1 pyramidal cells. However, the underlying mechanism of action of melamine is unclear, and it is unknown if the CA3-CA1 pathway is directly involved. In the present study, a whole-cell patch-clamp technique was employed to investigate the effect of melamine on the hippocampal CA3-CA1 pathway in vitro. Both the evoked excitatory postsynaptic current (eEPSC) and the paired-pulse ratio (PPR) were recorded. Furthermore, we examined whether autophagy was involved in glutamatergic transmission alterations induced by melamine. Our data showed that melamine significantly increased the amplitude of eEPSCs in a dose-dependent manner. Inhibition of the N-methyl-D-aspartic acid receptor did not prevent the increase in eEPSC amplitude. In addition, the PPR was remarkably decreased by a melamine concentration of 5 × 10(-5) g/mL. It was found that autophagy could be activated by melamine and an autophagy inhibitor, 3-MA, prevented the melamine-induced increase in eEPSC amplitude. Overall, our results show that melamine presynaptically alters glutamatergic synaptic transmission of hippocampal CA3-CA1 synapses in vitro and this is likely associated with autophagy alteration. PMID:26530910

  19. Enhancement of an outwardly rectifying chloride channel in hippocampal pyramidal neurons after cerebral ischemia.

    Science.gov (United States)

    Li, Jianguo; Chang, Quanzhong; Li, Xiaoming; Li, Xiawen; Qiao, Jiantian; Gao, Tianming

    2016-08-01

    Cerebral ischemia induces delayed, selective neuronal death in the CA1 region of the hippocampus. The underlying molecular mechanisms remain unclear, but it is known that apoptosis is involved in this process. Chloride efflux has been implicated in the progression of apoptosis in various cell types. Using both the inside-out and whole-cell configurations of the patch-clamp technique, the present study characterized an outwardly rectifying chloride channel (ORCC) in acutely dissociated pyramid neurons in the hippocampus of adult rats. The channel had a nonlinear current-voltage relationship with a conductance of 42.26±1.2pS in the positive voltage range and 18.23±0.96pS in the negative voltage range, indicating an outward rectification pattern. The channel is Cl(-) selective, and the open probability is voltage-dependent. It can be blocked by the classical Cl(-) channel blockers DIDS, SITS, NPPB and glibenclamide. We examined the different changes in ORCC activity in CA1 and CA3 pyramidal neurons at 6, 24 and 48h after transient forebrain ischemia. In the vulnerable CA1 neurons, ORCC activity was persistently enhanced after ischemic insult, whereas in the invulnerable CA3 neurons, no significant changes occurred. Further analysis of channel kinetics suggested that multiple openings are a major contributor to the increase in channel activity after ischemia. Pharmacological blockade of the ORCC partly attenuated cell death in the hippocampal neurons. We propose that the enhanced activity of ORCC might contribute to selective neuronal damage in the CA1 region after cerebral ischemia, and that ORCC may be a therapeutic target against ischemia-induced cell death. PMID:27181516

  20. Pyramid Comet Sampler Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Based on the sampling requirements, we propose an Inverted Pyramid sampling system. Each face of the pyramid includes a cutting blade which is independently...

  1. Numerical integration over pyramids

    OpenAIRE

    Chen, Ch.; Křížek, M.; Liu, L

    2013-01-01

    Pyramidal elements are often used to connect tetrahedral and hexahedral elements in the finite element method. In this paper we derive three new higher order numerical cubature formulae for pyramidal elements.

  2. Leptin Induces a Novel Form of NMDA Receptor-Dependent LTP at Hippocampal Temporoammonic-CA1 Synapses 1,2,3

    OpenAIRE

    Luo, Xiao; McGregor, Gemma; Irving, Andrew J; Harvey, Jenni

    2015-01-01

    Abstract It is well documented that the hormone leptin regulates many central functions and that hippocampal CA1 pyramidal neurons are a key target for leptin action. Indeed, leptin modulates excitatory synaptic transmission and synaptic plasticity at the Schaffer-collateral input to CA1 neurons. However the impact of leptin on the direct temporoammonic (TA) input to CA1 neurons is not known. Here we show that leptin evokes a long-lasting increase [long-term potentiation (LTP)] in excitatory ...

  3. Effects of baclofen on synaptically-induced cell firing in the rat hippocampal slice.

    OpenAIRE

    Ault, B.; Nadler, J V

    1983-01-01

    The effects of baclofen on the synaptically-induced firing of pyramidal and granule cell populations were tested in the rat hippocampal slice. Population spikes were evoked by stimulating excitatory pathways in the presence and absence of bath-applied drug. (+/-)-Baclofen (20 microM) completely blocked the firing of CA1 or CA3 hippocampal pyramidal cells subsequent to stimulation of projections that originate in area CA3. In contrast, the firing of dentate granule cells evoked by stimulation ...

  4. Baclofen activates voltage-dependent and 4-aminopyridine sensitive K+ conductance in guinea-pig hippocampal pyramidal cells maintained in vitro.

    OpenAIRE

    M. Inoue; T. Matsuo; Ogata, N.

    1985-01-01

    The ionic mechanism underlying the effect of (-)-baclofen in the hippocampus was investigated using guinea-pig brain slices. (-)-Baclofen either perfused or applied directly by microiontophoresis hyperpolarized the membrane and decreased the membrane input resistance of pyramidal cells in a dose-dependent manner. The value of the reversal potential for the baclofen-induced hyperpolarization, as estimated from the current-voltage relationships, was about -95mV. The reversal potential of the ba...

  5. M-type potassium channels modulate Schaffer collateral-CA1 glutamatergic synaptic transmission.

    Science.gov (United States)

    Sun, Jianli; Kapur, Jaideep

    2012-08-15

    Previous studies have suggested that muscarinic receptor activation modulates glutamatergic transmission. M-type potassium channels mediate the effects of muscarinic activation in the hippocampus, and it has been proposed that they modulate glutamatergic synaptic transmission. We tested whether M1 muscarinic receptor activation enhances glutamatergic synaptic transmission via the inhibition of the M-type potassium channels that are present in Schaffer collateral axons and terminals. Miniature excitatory postsynaptic currents (mEPSCs) were recorded from CA1 pyramidal neurons. The M1 receptor agonist, NcN-A-343, increased the frequency of mEPSCs, but did not alter their amplitude. The M-channel blocker XE991 and its analogue linopirdine also increased the frequency of mEPSCs. Flupirtine, which opens M-channels, had the opposite effect. XE991 did not enhance mEPSCs frequency in a calcium-free external medium. Blocking P/Q- and N-type calcium channels abolished the effect of XE991 on mEPSCs. These data suggested that the inhibition of M-channels increases presynaptic calcium-dependent glutamate release in CA1 pyramidal neurons. The effects of these agents on the membrane potentials of presynaptic CA3 pyramidal neurons were studied using current clamp recordings; activation of M1 receptors and blocking M-channels depolarized neurons and increased burst firing. The input resistance of CA3 neurons was increased by the application of McN-A-343 and XE991; these effects were consistent with the closure of M-channels. Muscarinic activation inhibits M-channels in CA3 pyramidal neurons and its efferents – Schaffer collateral, which causes the depolarization, activates voltage-gated calcium channels, and ultimately elevates the intracellular calcium concentration to increase the release of glutamate on CA1 pyramidal neurons. PMID:22674722

  6. Kinetic changes and modulation by carbamazepine on voltage-gated sodium channels in rat CA1 neurons after epilepsy

    Institute of Scientific and Technical Information of China (English)

    Guang-chun SUN; Taco WERKMAN; Wytse J WADMAN

    2006-01-01

    Aim: To study whether the functional properties of sodium channels, and subsequently the channel modulation by carbamazepine (CBZ) in hippocampal CA1 neurons can be changed after epileptic seizures. Methods: We used the acutely dissociated hippocampal CA1 pyramidal cells from epilepsy model rats 3 weeks and 3 months respectively after kainate injection, and whole-cell voltage-clamp techniques. Results: After long-term epileptic seizures, both sodium channel voltage-dependence of activation and steady-state inactivation shifted to more hyperpolarizing potentials, which resulted in the enlarged window current; the membrane density of sodium current decreased and the time constant of recovery from inactivation increased. CBZ displayed unchanged efficacy on sodium channels, with a similar binding rate to them, except that at higher concentrations, the voltage shift of inactivation was reduced. For the short-term kainate model rats, no differences were detected between the control and epilepsy groups. Conclusion: These results indicate that the properties of sodium channels in acutely dissociated hippocampal neurons could be changed following long-term epilepsy, but the alternation might not be enough to induce the channel resistance to CBZ.

  7. The Corporate Pyramid Fable

    OpenAIRE

    Steven A. Bank and Brian R. Cheffins

    2010-01-01

    Although corporate pyramids are currently commonplace world-wide and although there have been "noteworthy pyramiders" in American business history, this controversial form of corporate organization is now a rarity in the United States. The conventional wisdom is that corporate pyramids disappeared in the U.S. when New Deal policymakers began taxing dividends paid to corporate shareholders. This version of events is more fable than truth. The introduction of the intercorporate dividend tax did...

  8. Some enkephalin- or VIP-immunoreactive hippocampal pyramidal cells contain neurofibrillary tangles in the brains of aged humans and persons with Alzheimer's disease.

    Science.gov (United States)

    Kulmala, H K

    1985-01-01

    Neurofibrillary tangles are one of the histopathological neuronal abnormalities present in normal aging and especially in Alzheimer's Disease. We have utilized immunocytochemical staining for neuropeptides followed by Congo red with gallocyanin counterstaining and polarized illumination to determine whether enkephalin (Enk), somatostatin (Som), cholecystokinin (CCK), or vasoactive intestinal polypeptide (VIP) are contained in neurons afflicted with such tangles. A few Enk- or VIP-immunoreactive pyramidal cells in field hl and subiculum were found to contain tangles. Many such Enk- or VIP-immunoreactive neurons and cells containing Som- or CCK-like immunoreactivity did not contain such tangles. PMID:2410823

  9. The Healthy Eating Pyramid

    Institute of Scientific and Technical Information of China (English)

    Jimmy; Lin

    2007-01-01

    Experts from the Harvard School of Public Health created the Healthy Eating Pyramid.The pyramid is about the links between diet and health and offers useable information to help people make better choices about what to eat. Remember:its base is daily exercise and weight control.

  10. Premature aging phenotype in mice lacking high affinity nicotinic receptors: region specific changes in layer V pyramidal cell morphology

    Directory of Open Access Journals (Sweden)

    Eleni Konsolaki

    2014-02-01

    accelerated cognitive aging, based on structural alterations and spatial learning deficits only evident in old animals (Zoli et al., 1999; Picciotto and Zoli, 2002. However a systematic comparison of neuronal microanatomy in adult and aged animals has not been done to date. In the present study adult (4-6months and old (22-24months WT and β2-/- animals were used to examine the respective contributions of age and genotype on neuronal structure. We focus on layer V pyramidal cells because: (i they constitute the main cortical output (DeFelipe and Farinas, 1992; Romand et al., 2011 (ii they are often reported to exhibit increased sensitivity to aging (Nakamura et al., 1985; Baskys et al., 1990; De Brabander et al., 1998; Turner et al., 2005; (iii they possess a high density of cholinergic terminals (Houser et al., 1985 and, in contrast to layer III cells, they exhibit strong presynaptic modulation by β2 containing nAChRs and are activated by nAChR stimulation (Poorthuis et al., 2013; hence they would be a sensitive readout for the lack of high affinity nicotinic receptors. Furthermore, to examine the degree of age-related vulnerability across distinct cortical areas we used YFP-H mice that express yellow fluorescent protein (YFP in specific populations of thick-tufted layer V pyramidal neurons across the cortical mantle (Feng et al., 2000; Sugino et al., 2006. We used mutants crossed with YFP+ mice in order to have the same labeled populations in both genotypes, and we examined cells in primary visual cortex (V1 and anterior cingulate cortex (ACC, two cortical regions that receive similar cholinergic inputs (McKinney et al., 1983; Jacobowitz and Creed, 1983; Everitt and Robbins, 1997; Laplante et al., 2005 but have distinct cytoarchitecture and functional role (Elston et al., 2005. We ask whether neurons in old β2-/- mice exhibit greater structural deficits than aged-matched controls and whether deficits appear in old age or are already present earlier. Brains from 21 adult

  11. Leptin protects hippocampal CA1 neurons against ischemic injury

    OpenAIRE

    Feng ZHANG; Chen, Jun

    2008-01-01

    Leptin is an adipose hormone with well characterized roles in regulating food intake and energy balance. A novel neuroprotective role for leptin has recently been discovered; however, the underlying mechanisms are not clearly defined. The purpose of this study was to determine whether leptin protects against delayed neuronal cell death in hippocampal CA1 following transient global cerebral ischemia in rats and to study the signaling mechanism responsible for the neuroprotective effects of lep...

  12. The OER Adoption Pyramid

    OpenAIRE

    Trotter, Henry; Cox, Glenda

    2016-01-01

    This Pyramid was developed in the course of a research paper focusing on why South African academics adopt OER or not. We understood that numerous factors shaped their choices, but it became apparent that some factors were "essential" to OER activity while others were merely "influential". To clarify which factors were required for any type of OER activity, we developed the OER Adoption Pyramid, which consolidates the factors into six hierarchically related categories: acc...

  13. m1 Acetylcholine Receptor Expression is Decreased in Hippocampal CA1 region of Aged Epileptic Animals

    OpenAIRE

    Cavarsan, Clarissa Fantin; Avanzi, Renata Della Torre; Queiroz, Claudio Marcos; Xavier, Gilberto Fernando; Mello, Luiz Eugênio; Covolan, Luciene

    2011-01-01

    In the present study, we investigated the possible additive effects of epilepsy and aging on the expression of m1 muscarinic acetylcholine receptors (AChR) in the rat hippocampus. Young (3 months) and Aged (20 months) male, Wistar rats were treated with pilocarpine to induce status epilepticus (SE). Immunohistochemical procedure for m1 AChR detection was performed 2 months after pilocarpine-induced SE. In the CA1 pyramidal region m1 AChR staining was significantly decreased in aged epileptic ...

  14. Morphometric study of cervical anterior horn cells and pyramidal tracts in medulla oblongata and the spinal cord in patients with cerebrovascular diseases.

    Science.gov (United States)

    Qiu, Y; Wada, Y; Otomo, E; Tsukagoshi, H

    1991-04-01

    To clarify the effect of damage to the upper motor neurons on lower motor neurons, quantitative studies were made regarding the cross-sectional area and the number of the individual anterior horn cells in the lateral nuclear cell groups of the 5th segment of the cervical spinal cord (C5), and regarding the cross-sectional areas of the pyramidal tract in the medulla, and in the spinal cord at the C5 and L2 levels. The subjects included 45 patients with cerebrovascular disease (CVD), and 50 age-matched controls without neurological disease. The medullary pyramid (MP) and the ventral funiculus (VF), ipsilateral to the hemispheric lesion, were compared with the MP and VF of the other, unaffected, side. The ventro-lateral funiculus (VLF), anterior horn (AH) and C5 anterior horn cell (AHC), contralateral to the lesion, were also compared with the VLF, AH, and AHC of the other, unaffected, side. The AHC area (mean cross-sectional area of anterior horn cells) and the MP area, VF area, VLF area, AH area (mean cross-sectional areas of MP, VF, VLF and AH) associated with the hemispheric lesional side were significantly decreased, compared with those of the unaffected sides and the controls. However, there was no significant difference in AHC number between the affected and unaffected sides in patients with CVD, nor between the affected side and the controls. In order to examine the relationship between a decrease in AHC area and degree of paralysis, CVD patients were divided into two groups according to degree of muscle strength: the severe and mild paralysis groups.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2072114

  15. Effects of carnosine on the evoked potentials in hippocampal CA1 region

    Institute of Scientific and Technical Information of China (English)

    Zhou-yan FENG; Xiao-jing ZHENG; Jing WANG

    2009-01-01

    Objective: To directly examine the effects of carnosine on neuronal excitation and inhibition in rat hippocampus in vivo. Methods: Artificial cerebrospinal fluid with carnosine was directly administrated over the exposed rat hippocampus. The changes of neuron activity in the CA1 region of hippocampus were evaluated by orthodromically- and antidromically-evoked potentials, as well as paired-pulse stimulation paradigm. Results: In both orthodromic and antidromic response potentials, carnosine transformed population spikes (PSs) with single spike into epileptiform multiple spikes. In addition, similar to the effect of γ-aminobutyric acidA (GABAA) antagonist picrotoxin, carnosine decreased paired-pulse stimulating depression significantly.However, no significant change was observed in the spontaneous field potentials during the application of carnosine. Conclusion:The results indicate a disinhibition-induced excitation effect of carnosine on the CA1 pyramidal neurons. It provides important information against the application of carnosine as a potential anticonvulsant in clinical treatment.

  16. Effects of electromagnetic radiation on spatial memory and synapses in rat hippocampal CA1

    Institute of Scientific and Technical Information of China (English)

    Yuhong Li; Changhua Shi; Guobing Lu; Qian Xu; Shaochen Liu

    2012-01-01

    In this study, we investigated the effects of mobile phone radiation on spatial learning, reference memory, and morphology in related brain regions. After the near-field radiation (0.52-1.08 W/kg) was delivered to 8-week-old Wistar rats 2 hours per day for 1 month, behavioral changes were examined using the Morris water maze. Compared with the sham-irradiated rats, the irradiated rats exhibited impaired performance. Morphological changes were investigated by examining synaptic ultrastructural changes in the hippocampus. Using the physical dissector technique, the number of pyramidal neurons, the synaptic profiles, and the length of postsynaptic densities in the CA1 region were quantified stereologically. The morphological changes included mitochondrial degenerations, fewer synapses, and shorter postsynaptic densities in the radiated rats. These findings indicate that mobile phone radiation can significantly impair spatial learning and reference memory and induce morphological changes in the hippocampal CA1 region.

  17. Conjunctive input processing drives feature selectivity in hippocampal CA1 neurons.

    Science.gov (United States)

    Bittner, Katie C; Grienberger, Christine; Vaidya, Sachin P; Milstein, Aaron D; Macklin, John J; Suh, Junghyup; Tonegawa, Susumu; Magee, Jeffrey C

    2015-08-01

    Feature-selective firing allows networks to produce representations of the external and internal environments. Despite its importance, the mechanisms generating neuronal feature selectivity are incompletely understood. In many cortical microcircuits the integration of two functionally distinct inputs occurs nonlinearly through generation of active dendritic signals that drive burst firing and robust plasticity. To examine the role of this processing in feature selectivity, we recorded CA1 pyramidal neuron membrane potential and local field potential in mice running on a linear treadmill. We found that dendritic plateau potentials were produced by an interaction between properly timed input from entorhinal cortex and hippocampal CA3. These conjunctive signals positively modulated the firing of previously established place fields and rapidly induced new place field formation to produce feature selectivity in CA1 that is a function of both entorhinal cortex and CA3 input. Such selectivity could allow mixed network level representations that support context-dependent spatial maps. PMID:26167906

  18. Spatial tuning and brain state account for dorsal hippocampal CA1 activity in a non-spatial learning task

    Science.gov (United States)

    Shan, Kevin Q; Lubenov, Evgueniy V; Papadopoulou, Maria; Siapas, Athanassios G

    2016-01-01

    The hippocampus is a brain area crucial for episodic memory in humans. In contrast, studies in rodents have highlighted its role in spatial learning, supported by the discovery of place cells. Efforts to reconcile these views have found neurons in the rodent hippocampus that respond to non-spatial events but have not unequivocally dissociated the spatial and non-spatial influences on these cells. To disentangle these influences, we trained freely moving rats in trace eyeblink conditioning, a hippocampally dependent task in which the animal learns to blink in response to a tone. We show that dorsal CA1 pyramidal neurons are all place cells, and do not respond to the tone when the animal is moving. When the animal is inactive, the apparent tone-evoked responses reflect an arousal-mediated resumption of place-specific firing. These results suggest that one of the main output stages of the hippocampus transmits only spatial information, even in this non-spatial task. DOI: http://dx.doi.org/10.7554/eLife.14321.001 PMID:27487561

  19. Baclofen and adenosine inhibition of synaptic transmission at CA3-CA1 synapses display differential sensitivity to K+ channel blockade.

    Science.gov (United States)

    Skov, Jane; Andreasen, Mogens; Hablitz, John J; Nedergaard, Steen

    2011-05-01

    The metabotropic GABA(B) and adenosine A(1) receptors mediate presynaptic inhibition through regulation of voltage-dependent Ca(2+) channels, whereas K(+) channel regulation is believed to have no role at the CA3-CA1 synapse. We show here that the inhibitory effect of baclofen (20 μM) and adenosine (300 μM) on field EPSPs are differentially sensitive to Cs(+) (3.5 mM) and Ba(2+) (200 μM), but not 4-aminopyridine (100 μM). Barium had no effect on paired-pulse facilitation (PPF) in itself, but gave significant reduction (14 ± 5%) when applied in the presence of baclofen, but not adenosine, suggesting that the effect is presynaptic and selective on the GABA(B) receptor-mediated response. The effect of Ba(2+) on PPF was not mimicked by tertiapin (30 nM), indicating that the underlying mechanism does not involve GIRK channels. Barium did not affect PPF in slices from young rats (P7-P8), suggesting developmental regulation. The above effects of Ba(2+) on adult tissue were reproduced when measuring evoked whole-cell EPSCs from CA1 pyramidal neurons: PPF was reduced by 22 ± 3% in the presence of baclofen and unaltered in adenosine. In contrast, Ba(2+) caused no significant change in frequency or amplitude of miniature EPSCs. The Ba(2+)-induced reduction of PPF was antagonized by LY341495, suggesting metabotropic glutamate receptor involvement. We propose that these novel effects of Ba(2+) and Cs(+) are exerted through blockade of inwardly rectifying K(+) channels in glial cells, which are functionally interacting with the GABA(B) receptor-dependent glutamate release that generates heterosynaptic depression. PMID:21274618

  20. Reduced Glutamatergic Currents and Dendritic Branching of Layer 5 Pyramidal Cells Contribute to Medial Prefrontal Cortex Deactivation in a Rat Model of Neuropathic Pain

    Science.gov (United States)

    Kelly, Crystle J.; Huang, Mei; Meltzer, Herbert; Martina, Marco

    2016-01-01

    Multiple studies have demonstrated that neuropathic pain is associated with major reorganization in multiple brain areas. In line with the strong emotional salience of chronic pain, involvement of the limbic system appears particularly important. Within the past few years, it has become clear that the functional deactivation of the prefrontal cortex (PFC) is critical for both the cognitive/emotional and the sensory components of pain. However, at the cellular level, details of this deactivation remain in large part unclear. Here we show that 1 week after a peripheral neuropathic injury (Spared Nerve Injury model) pyramidal cells in layer 5 (L5) of the rat medial PFC show responses to excitatory glutamatergic inputs that are reduced by about 50%, as well as reduced frequency of spontaneous excitatory synaptic currents. Additionally, these cells have reduced membrane capacitance and increased input resistance. All these findings are consistent with decreased dendritic length, thus we performed a detailed morphological analysis on a subset of the recorded neurons. We found that the apical dendrites proximal to the soma (excluding the tuft) are shorter and less complex in SNI animals, in agreement with the reduced capacitance and glutamatergic input. Finally, we used in vivo microdialysis to compare the basal concentrations of glutamate and GABA in the PFC of sham and SNI rats and found that ambient glutamate is decreased in SNI rats. Taken together, these data show that impaired glutamatergic transmission contributes to the functional deactivation of the mPFC in neuropathic pain. Additionally, the reduced branching of apical dendrites of L5 pyramidal neurons may underlay the gray matter reduction in chronic pain.

  1. Hippocampal CA1 Ripples as Inhibitory Transients.

    Science.gov (United States)

    Malerba, Paola; Krishnan, Giri P; Fellous, Jean-Marc; Bazhenov, Maxim

    2016-04-01

    Memories are stored and consolidated as a result of a dialogue between the hippocampus and cortex during sleep. Neurons active during behavior reactivate in both structures during sleep, in conjunction with characteristic brain oscillations that may form the neural substrate of memory consolidation. In the hippocampus, replay occurs within sharp wave-ripples: short bouts of high-frequency activity in area CA1 caused by excitatory activation from area CA3. In this work, we develop a computational model of ripple generation, motivated by in vivo rat data showing that ripples have a broad frequency distribution, exponential inter-arrival times and yet highly non-variable durations. Our study predicts that ripples are not persistent oscillations but result from a transient network behavior, induced by input from CA3, in which the high frequency synchronous firing of perisomatic interneurons does not depend on the time scale of synaptic inhibition. We found that noise-induced loss of synchrony among CA1 interneurons dynamically constrains individual ripple duration. Our study proposes a novel mechanism of hippocampal ripple generation consistent with a broad range of experimental data, and highlights the role of noise in regulating the duration of input-driven oscillatory spiking in an inhibitory network. PMID:27093059

  2. Hippocampal CA1 Ripples as Inhibitory Transients.

    Directory of Open Access Journals (Sweden)

    Paola Malerba

    2016-04-01

    Full Text Available Memories are stored and consolidated as a result of a dialogue between the hippocampus and cortex during sleep. Neurons active during behavior reactivate in both structures during sleep, in conjunction with characteristic brain oscillations that may form the neural substrate of memory consolidation. In the hippocampus, replay occurs within sharp wave-ripples: short bouts of high-frequency activity in area CA1 caused by excitatory activation from area CA3. In this work, we develop a computational model of ripple generation, motivated by in vivo rat data showing that ripples have a broad frequency distribution, exponential inter-arrival times and yet highly non-variable durations. Our study predicts that ripples are not persistent oscillations but result from a transient network behavior, induced by input from CA3, in which the high frequency synchronous firing of perisomatic interneurons does not depend on the time scale of synaptic inhibition. We found that noise-induced loss of synchrony among CA1 interneurons dynamically constrains individual ripple duration. Our study proposes a novel mechanism of hippocampal ripple generation consistent with a broad range of experimental data, and highlights the role of noise in regulating the duration of input-driven oscillatory spiking in an inhibitory network.

  3. Dependence of NMDA/GSK-3β Mediated Metaplasticity on TRPM2 Channels at Hippocampal CA3-CA1 Synapses

    Directory of Open Access Journals (Sweden)

    Xie Yu-Feng

    2011-12-01

    Full Text Available Abstract Transient receptor potential melastatin 2 (TRPM2 is a calcium permeable non-selective cation channel that functions as a sensor of cellular redox status. Highly expressed within the CNS, we have previously demonstrated the functional expression of these channels in CA1 pyramidal neurons of the hippocampus. Although implicated in oxidative stress-induced neuronal cell death, and potentially in neurodegenerative disease, the physiological role of TRPM2 in the central nervous system is unknown. Interestingly, we have shown that the activation of these channels may be sensitized by co-incident NMDA receptor activation, suggesting a potential contribution of TRPM2 to synaptic transmission. Using hippocampal cultures and slices from TRPM2 null mice we demonstrate that the loss of these channels selectively impairs NMDAR-dependent long-term depression (LTD while sparing long-term potentiation. Impaired LTD resulted from an inhibition of GSK-3β, through increased phosphorylation, and a reduction in the expression of PSD95 and AMPARs. Notably, LTD could be rescued in TRPM2 null mice by recruitment of GSK-3β signaling following dopamine D2 receptor stimulation. We propose that TRPM2 channels play a key role in hippocampal synaptic plasticity.

  4. Building the next pyramid

    CERN Document Server

    West, Joseph; Waters, Kevin; Ward, Stephen; Ward, Tia

    2015-01-01

    The results of experimental tests of a novel method for moving large (pyramid construction size) stone blocks by rolling them are presented. The method is implemented by tying 12 identical rods of appropriately chosen radius to the faces of the block forming a rough dodecagon prism. Experiments using a 1,000 kg block show that it can be moved across level open ground with a dynamic coefficient of friction of less than 0.06. This value is a factor of five lower than that obtained for dragging the block, and the best values reported for dragging by others, at 0.3. the results are more dramatic than those obtained on smaller scale experiments on a 29.6 kg block, also reported here. For full scale pyramid blocks, the wooden "rods" woudl need to be posts of order 30 cm in diameter, similar in size to those used as masts on ships in the Nile.

  5. Numerical integration over pyramids

    Czech Academy of Sciences Publication Activity Database

    Chen, Ch.; Křížek, Michal; Liu, L.

    2013-01-01

    Roč. 5, č. 3 (2013), s. 309-320. ISSN 2070-0733 R&D Projects: GA AV ČR(CZ) IAA100190803 Institutional research plan: CEZ:AV0Z10190503 Keywords : reference pyramidal element * nonlinear systems of algebraic equations * Bramble-Hilbert lemma Subject RIV: BA - General Mathematics Impact factor: 0.645, year: 2013 http://www.global-sci.org/aamm/readabs.php?vol=5&no=3&doc=309&year=2013&ppage=320

  6. Imaging the Cheops Pyramid

    CERN Document Server

    Bui, H D

    2012-01-01

    In this book Egyptian Archeology  and Mathematics meet. The author is an expert in theories and applications in Solid Mechanics and Inverse Problems, a former professor at Ecole Polytechnique and now works with Electricité de France on maintenance operations on nuclear power plants. In the Autumn of 1986, after the end of the operation on the King’s chamber conducted under the Technological and Scientific Sponsorship of EDF, to locate a cavity, he was called to solve a mathematical inverse problem, to find the unknown tomb of the King and the density structure of the whole pyramid based on measurements of microgravity made inside and outside of the pyramid. This book recounts the various search operations on the pyramid of Cheops made at the request of the Egyptian and French authorities in 1986-1987. After the premature end of the Cheops operation in the Autumn of 1986, following the fiasco of unsuccessful drillings in the area suspected by both architects G. Dormion and J.P. Goidin and microgravity aus...

  7. Improvement of polycrystalline silicon wafer solar cell efficiency by forming nanoscale pyramids on wafer surface using a self-mask etching technique.

    Science.gov (United States)

    Lin, Hsin-Han; Chen, Wen-Hwa; Hong, Franklin C-N

    2013-05-01

    The creation of nanostructures on polycrystalline silicon wafer surface to reduce the solar reflection can enhance the solar absorption and thus increase the solar-electricity conversion efficiency of solar cells. The self-masking reactive ion etching (RIE) was studied to directly fabricate nanostructures on silicon surface without using a masking process for antireflection purpose. Reactive gases comprising chlorine (Cl2), sulfur hexafluoride (SF6), and oxygen (O2) were activated by radio-frequency plasma in an RIE system at a typical pressure of 120-130 mTorr to fabricate the nanoscale pyramids. Poly-Si wafers were etched directly without masking for 6-10 min to create surface nanostructures by varying the compositions of SF6, Cl2, and O2 gas mixtures in the etching process. The wafers were then treated with acid (KOH:H2O = 1:1) for 1 min to remove the damage layer (100 nm) induced by dry etching. The damage layer significantly reduced the solar cell efficiencies by affecting the electrical properties of the surface layer. The light reflectivity from the surface after acid treatment could be significantly reduced to etching. PMID:23847751

  8. Localization of the cannabinoid CB1 receptor and the 2-AG synthesizing (DAGLα and degrading (MAGL, FAAH enzymes in cells expressing the Ca2+-binding proteins calbindin, calretinin and parvalbumin in the adult rat hippocampus

    Directory of Open Access Journals (Sweden)

    Patricia eRivera

    2014-06-01

    Full Text Available The retrograde suppression of the synaptic transmission by the endocannabinoid sn-2-arachidonoylglycerol (2-AG is mediated by the cannabinoid CB1 receptors and requires the elevation of intracellular Ca2+ and the activation of specific 2-AG synthesizing (i.e. DAGLα enzymes. However, the anatomical organization of the neuronal substrates that express 2-AG/CB1 signaling system-related molecules associated with selective Ca2+-binding proteins (CaBPs is still unknown. For this purpose, we used double-label immunofluorescence and confocal laser scanning microscopy for the characterization of the expression of the 2-AG/CB1 signaling system (CB1 receptor, DAGLα, MAGL and FAAH and the CaBPs calbindin D28k, calretinin and parvalbumin in the rat hippocampus. CB1, DAGLα and MAGL labeling was mainly localized in fibers and neuropil, which were differentially organized depending on the hippocampal CaBPs-expressing cells. CB1+ fiber terminals localized in all hippocampal principal cell layers were tightly attached to calbindin+ cells (granular and pyramidal neurons, and calretinin+ and parvalbumin+ interneurons. DAGLα neuropil labeling was selectively found surrounding calbindin+ principal cells in the dentate gyrus and CA1, and in the calretinin+ and parvalbumin+ interneurons in the pyramidal cell layers of the CA1/3 fields. MAGL+ terminals were only observed around CA1 calbindin+ pyramidal cells, CA1/3 calretinin+ interneurons and CA3 parvalbumin+ interneurons localized in the pyramidal cell layers. Interestingly, calbindin+ pyramidal cells expressed FAAH specifically in the CA1 field. The identification of anatomically related-neuronal substrates that expressed 2-AG/CB1 signaling system and selective CaBPs should be considered when analyzing the cannabinoid signaling associated with hippocampal functions.

  9. 大鼠海马CA1区前馈抑制和反馈抑制的作用特性%Effect Features of Feedforward and Feedback Inhibitions on Hippocampal CA 1 Region of Rat.

    Institute of Scientific and Technical Information of China (English)

    封洲燕; 邢昊昱; 田聪; 王静; 汪洋

    2011-01-01

    目的 研究前馈抑制和反馈抑制在控制大脑海马组织CA1锥体神经元动作电位发放中各自的作用强度随时间变化的特性.方法 在大鼠海马CA1区的输入通路Schaffer侧支和输出通路alveus上分别植入正向和反向刺激电极.在锥体神经元胞体层记录正向和反向双刺激诱发的群峰电位,并利用双正向、先反后正以及先正后反的不同双刺激组合的响应,分析计算两种抑制的作用,在体分别考察它们的短时程作用过程.结果 两种抑制的协同作用在第一个刺激后的50 ms内比较强,第二个刺激诱发的群峰电位的抑制超过50%,在10 ms以内则几乎完全被抑制.并且,在10~50 ms,随时间的缩短,反馈抑制作用的比例增大;但在3~7 ms时间段存在明显的反馈抑制减弱时期.结论 反馈抑制作用期与动作电位不应期之间并不能衔接,是快速有力的前馈抑制作用补充了反馈抑制与不应期之间的抑制减弱期.%Objective To investigate the temporal features of both feed-forward inhibition and feedback inhibition in local neural circuitry of hippocampus that control the action potential firings of pyramidal neurons.Methods Orthodromic- and antidromic-stimulating electrodes were implanted in the Schaffer collateral and alveus of hippocampal CA1 region, respectively.The orthodromic- and antidromic-evoked population spikes (PS) were recorded in the pyramidal cell layer in vivo by using different combinations of orthodromic and antidromic paired-pulse stimulations, including double orthodromic-stimuli, antidromic-orthodromic-stimuli and orthodromic-antidromic-stimuli, with varied inter-pulse intervals.The temporal changes in the two types of inhibition were estimated separately within short latencies.Results The corporate effects of both inhibitions within 50 ms latency following the first stimulus was strong enough to suppress more than 50% of PS amplitudes in the response evoked by the second

  10. Protective roles of heat stress on the neurons in hippocampal CA1 region of mice

    Institute of Scientific and Technical Information of China (English)

    WANG Chunxu; WANG Hanxing

    2007-01-01

    The effects of heat stress on the neurons in hippocampal CA1 region of brain ischemia/reperfusion were explored.The mice were pretreated with heat stress followed by ischemia/reperfusion by clipping bilateral cervical common arteries for 7 min.Mice were divided randomly into four groups as follows:(1)normal control group;(2)heat stress pretreated subsequent to ischemia/reperfusion group (HS/IR);(3)ischemia/reperfusion group(IR);and(4)heat stress group(HS).Animals in the last three groups were subdivided into three subgroups:1 d,4 d,14 d respectively.The Morris water maze was used to test the ability of learning and memorizing,Nissl staining was used to count the average number of survived neurons in hippocampal CA1 region,and immunohistochemistry combined with image analysis system to detect the changes of Microtubule associated protein 2 (MAP-2)expression.The results showed that mice in IR group exhibited increased escape latency when compared with that of normal,HS and HS/IR groups(P<0.01),and the mice in IR group adopted an inefficient search strategy,major in circling and restricted searching manners.Nissl staining results showed a significant reduction in the number of pyramidal neurons in hippocampal CA1 regions in HS/IR and IR groups,with a decrease in IR group(P<0.01).Compared with normal group,the expression of MAP-2 in hippocampal CA1 region obviously decreased in IR group(P<0.05).The present results indicate that heat stress pretreatment can improve the spatial learning and memorizing function through protection to hippocampal neurons.

  11. Activation of p42/44 mitogen-activated protein kinase pathway in long-term potentiation induced by nicotine in hippocampal CA1 region in rats%在烟碱诱导的大鼠海马CA1区长时程增强形成中p42/44促细胞分裂剂活化的蛋白激酶通路被激活

    Institute of Scientific and Technical Information of China (English)

    王捷; 陈远宾; 朱小南; 陈汝筑

    2001-01-01

    目的:研究p42/44 MAPK通路在烟碱诱导大鼠海马CA1区长时程增强(LTP)形成中的作用.方法:细 胞外场电位记录离体海马脑片CA1区锥体细胞层群体峰电位;蛋白质印迹检测p42/44 MAPK磷酸化程度及其总蛋白表达.结果:PD98059 25 μmol/L和50 μmol/L呈剂量依赖性抑制烟碱(10 μmol/L)诱导大鼠海马CA1区LTP的形成;在烟碱诱导LTP形成的海马CA1区组织内p42和p44 MAPK磷酸化均明显增强并有p42和p44 MAPK总蛋白表达量的增加.结论:p42/44 MAPK通路参与烟碱诱导大鼠海马CA1区LTP形成的信号转导过程.%AIM: To investigate the relationship between activation of p42/44 mitogen-activated protein kinase .(MAPK)pathway and hippocampal long term potentiation (LTP)induced by nicotine in area CA1. METHODS: Extracellular recording of population spike (PS) was performed within the pyramidal cell layer of hippocampal area CAl in vitro; Western blot analysis was employed to detect the active phosphorylated state and the total protein expression of p42/44 MAPK. RESULTS: PD98059concentration-dependently (25 μmol/L, 50 μmol/L) attenuated the induction of LTP induced by nicotine 10 μmol/L; both p42 and p44 MAPK were activated with their total protein expression increasing in CA1 subregion in response to LTP induced by nicotine. CONCLUSION: Activation of p42/44 MAPK pathway is required for hippocampal LTP induced by nicotine.

  12. Structural changes in pyramidal cell dendrites and synapses in the unaffected side of the sensorimotor cortex following transcranial magnetic stimulation and rehabilitation training in a rat model of focal cerebral infarct

    Institute of Scientific and Technical Information of China (English)

    Chuanyu Liu; Surong Zhou; Xuwen Sun; Zhuli Liu; Hongliang Wu; Yuanwu Mei

    2011-01-01

    Very little is known about the effects of transcranial magnetic stimulation and rehabilitation training on pyramidal cell dendrites and synapses of the contralateral, unaffected sensorimotor cortex in a rat model of focal cerebral infarct. The present study was designed to explore the mechanisms underlying improved motor function via transcranial magnetic stimulation and rehabilitation training following cerebral infarction. Results showed that rehabilitation training or transcranial magnetic stimulation alone reduced neurological impairment in rats following cerebral infarction, as well as significantly increased synaptic curvatures and post-synaptic density in the non-injured cerebral hemisphere sensorimotor cortex and narrowed the synapse cleft width. In addition, the percentage of perforated synapses increased. The combination of transcranial magnetic stimulation and rehabilitation resulted in significantly increased total dendritic length, dendritic branching points, and dendritic density in layer V pyramidal cells of the non-injured cerebral hemisphere motor cortex.These results demonstrated that transcranial magnetic stimulation and rehabilitation training altered structural parameters of pyramidal cell dendrites and synapses in the non-injured cerebral hemisphere sensorimotor cortex, thereby improving the ability to compensate for neurological functions in rats following cerebral infarction.

  13. Pyramid Lake Renewable Energy Project

    Energy Technology Data Exchange (ETDEWEB)

    John Jackson

    2008-03-14

    The Pyramid Lake Paiute Tribe is a federally recognized Tribe residing on the Pyramid Lake Reservation in western Nevada. The funding for this project was used to identify blind geothermal systems disconnected from geothermal sacred sites and develop a Tribal energy corporation for evaluating potential economic development for profit.

  14. PYRAMID LAKE RENEWEABLE ENERGY PLAN

    Energy Technology Data Exchange (ETDEWEB)

    HIGH DESERT GEOCULTURE, LLC

    2009-06-06

    The Pyramid Lake Renewable Energy Plan covers these areas: energy potential (primarily focusing on geothermal resource potential, but also more generally addressing wind energy potential); renewable energy market potential; transmission system development; geothermal direct use potential; and business structures to accomplish the development objectives of the Pyramid Lake Paiute Tribe.

  15. Quasi-Convolution Pyramidal Blurring

    Directory of Open Access Journals (Sweden)

    Martin Kraus

    2009-12-01

    Full Text Available Efficient image blurring techniques based on the pyramid algorithm can be implemented on modern graphics hardware; thus, image blurring with arbitrary blur width is possible in real time even for large images. However, pyramidal blurring methods do not achieve the image quality provided by convolution filters; in particular, the shape of the corresponding filter kernel varies locally, which potentially results in objectionable rendering artifacts. In this work, a new analysis filter is designed that significantly reduces this variation for a particular pyramidal blurring technique. Moreover, the pyramidal blur algorithm is generalized to allow for a continuous variation of the blur width. Furthermore, an efficient implementation for programmable graphics hardware is presented. The proposed method is named “quasi-convolution pyramidal blurring” since the resulting effect is very close to image blurring based on a convolution filter for many applications.

  16. Estimates of volumes and pyramidal cell numbers in the prelimbic subarea of the prefrontal cortex in experimental hypothyroid rats.

    OpenAIRE

    Madeira, M. D.; A. Pereira; Cadete-Leite, A; Paula-Barbosa, M M

    1990-01-01

    In previous quantitative studies we demonstrated that the volumes of the cerebellar and hippocampal granular layers, as well as their total number of cells, were reduced in 30 days old hypothyroid rats. We decided to extend these studies to the prelimbic subarea of the medial prefrontal cortex using the same morphometric procedures. The cortical volume and the total number of neurons of its Layer III were determined. After correcting for the tissue shrinkage factor, it was found that the volu...

  17. Hypothermia rescues hippocampal CA1 neurons and attenuates down-regulation of the AMPA receptor GluR2 subunit after forebrain ischemia

    OpenAIRE

    Colbourne, Frederick; Grooms, Sonja Y.; Zukin, R. Suzanne; Buchan, Alastair M.; Bennett, Michael V. L.

    2003-01-01

    Brief forebrain ischemia in rodents induces selective and delayed neuronal death, particularly of hippocampal CA1 pyramidal neurons. Neuronal death is preceded by down-regulation specific to CA1 of GluR2, the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunit that limits Ca2+ influx. This alteration is hypothesized to cause neurodegeneration by permitting a lethal influx of Ca2+ and/or Zn2+ through newly formed GluR2-lacking AMPA receptors. Two days of mild hypotherm...

  18. The effect of two lipophilic gamma-aminobutyric acid uptake blockers in CA1 of the rat hippocampal slice

    DEFF Research Database (Denmark)

    Rekling, J C; Jahnsen, H; Mosfeldt Laursen, A

    1990-01-01

    the blood. 2. We have investigated the effect of these two uptake inhibitors on the responses to exogenous GABA and on GABA-mediated inhibitory synaptic potentials in pyramidal neurones of the CA1 region in the rat hippocampal slice. 3. We found that both drugs increased the amplitude and duration of...... responses to exogenous GABA. Furthermore, the inhibitory synaptic potentials increased in amplitude. This increase was seen in both early and late phases of the synaptic potentials. We conclude that NO-05-0328 and NO-05-0329, at least in vitro, are more effective than older GABA uptake inhibitors such as...

  19. Low doses of alcohol potentiate GABA sub B inhibition of spontaneous activity of hippocampal CA1 neurons in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Criado, J.R.; Thies, R. (Univ. of Oklahoma, Oklahoma City (United States))

    1991-03-11

    Low doses of alcohol facilitate firing of hippocampal neurons. Such doses also enhance the inhibitory actions of GABA. Alcohol is known to potentiate inhibition via GABA{sub A} receptors. However, the effects of alcohol on GABA{sub B} receptor function are not understood. Spontaneous activity of single units was recorded from CA1 neurons of male rats anesthetized with 1.0% halothane. Electrical recordings and local application of drugs were done with multi-barrel pipettes. CA1 pyramidal neurons fired spontaneous bursts of action potentials. Acute alcohol decreased the interval between bursts, a mild excitatory action. Alcohol also more than doubled the period of complete inhibition produced by local application of both GABA and baclofen. These data suggest that GABA{sub B}-mediated inhibition is also potentiated by low doses of alcohol.

  20. Effects of inhaled anesthetic isoflurane on long-term potentiation of CA3 pyramidal cell afferents in vivo

    Directory of Open Access Journals (Sweden)

    Ballesteros KA

    2012-11-01

    Full Text Available Kristen A Ballesteros,1 Angela Sikorski,2 James E Orfila,3 Joe L Martinez Jr41Department of Biology, The University of Texas at San Antonio, San Antonio, TX, USA; 2Texas A&M University Texarkana, Texarkana, TX, USA; 3University of Colorado in Denver, Denver, CO, USA; 4University of Illinois in Chicago, Chicago, IL, USAAbstract: Isoflurane is a preferred anesthetic, due to its properties that allow a precise concentration to be delivered continually during in vivo experimentation. The major mechanism of action of isoflurane is modulation of the γ-amino butyric acid (GABAA receptor-chloride channel, mediating inhibitory synaptic transmission. Animal studies have shown that isoflurane does not cause cell death, but it does inhibit cell growth and causes long-term hippocampal learning deficits. As there are no studies characterizing the effects of isoflurane on electrophysiological aspects of long-term potentiation (LTP in the hippocampus, it is important to determine whether isoflurane alters the characteristic responses of hippocampal afferents to cornu ammonis region 3 (CA3. We investigated the effects of isoflurane on adult male rats during in vivo induction of LTP, using the mossy fiber pathway, the lateral perforant pathway, the medial perforant pathway, and the commissural CA3 (cCA3 to CA3, with intracranial administration of Ringer’s solution, naloxone, RS-aminoindan-1, 5-dicarboxylic acid (AIDA, or 3-[(R-2-carboxypiperazin-4-yl]-propo-2-enyl-1-phosphonic acid (CPP. Then, we compared these responses to published electrophysiological data, using sodium pentobarbital as an anesthetic, under similar experimental conditions. Our results showed that LTP was exhibited in animals anesthetized with isoflurane under vehicle conditions. With the exception of AIDA in the lateral perforant pathway, the defining characteristics of the four pathways appeared to remain intact, except for the observation that LTP was markedly reduced in animals

  1. Correspondences between Pre-pyramids, Pyramids and Robinsonian Dissimilarities

    OpenAIRE

    Bertrand, Patrice; Diatta, Jean; Jean, Diatta

    2013-01-01

    We consider cluster structures in a general setting where they do not necessarily contain all singletons of the ground set. Then we provide a direct proof of the bijection between semi-proper robinsonian dissimilarities and indexed pre-pyramids. This result generalizes its analogue proven by Batbedat in the particular case of definite cluster structures. Moreover, the proposed proof shows that the clusters of the indexed pre-pyramid corresponding to a semi-proper robinsonian dissimilarity are...

  2. The Pyramidal Capacitated Vehicle Routing Problem

    DEFF Research Database (Denmark)

    Lysgaard, Jens

    This paper introduces the Pyramidal Capacitated Vehicle Routing Problem (PCVRP) as a restricted version of the Capacitated Vehicle Routing Problem (CVRP). In the PCVRP each route is required to be pyramidal in a sense generalized from the Pyramidal Traveling Salesman Problem (PTSP). A pyramidal...

  3. The pyramidal capacitated vehicle routing problem

    DEFF Research Database (Denmark)

    Lysgaard, Jens

    2010-01-01

    This paper introduces the pyramidal capacitated vehicle routing problem (PCVRP) as a restricted version of the capacitated vehicle routing problem (CVRP). In the PCVRP each route is required to be pyramidal in a sense generalized from the pyramidal traveling salesman problem (PTSP). A pyramidal...

  4. Interactive Visualization of Graph Pyramids

    OpenAIRE

    Kerren, Andreas

    2006-01-01

    Hierarchies of plane graphs, called graph pyramids, can be used for collecting, storing and analyzing geographical information based on satellite images or other input data. The visualization of graph pyramids facilitates studies about their structure, such as their vertex distribution or height in relation of a specific input image. Thus, a researcher can debug algorithms and ask for statistical information. Furthermore, it improves the better understanding of geographical data, like land...

  5. Changes of NMDA receptors-mediated eEPSC in hippocampal CA1 region of the DCDs rat models%NMDA受体介导的eEPSC在皮质发育障碍动物模型海马CA1区的改变

    Institute of Scientific and Technical Information of China (English)

    张建刚; 宋延波; 张毅; 贺兴; 冯飞; 晏勇

    2011-01-01

    目的:研究皮质发育障碍(DCD)大鼠模型海马CA1区N-甲基-D-门冬氨酸(NMDA)受体及a-氨基-3-羧基-5-甲基异恶唑-4-丙酸(AmPA)受体介导的兴奋性突触后电流(eEPSC)的变化,探讨DCD大鼠模型的致(癎)机制.方法:选取出生10-20dDCD幼鼠模型和正常对照组,应用可视法脑片膜片钳记录方法,记录大鼠海马CA1区锥体神经元的NMDA受体及AmPA受体介导的eEPSC幅度及衰减时间常数.结果:DCD模型组与正常对照组相比,NMDA受体介导的eEPSC的幅度有明显增高[(119.54±10.97)pAvs(83.69±10.23)pA;P0.05]无明显改变.结论:NMDA受体介导的异常突触后反应在DCD的致痴机制方面起到重要的作用.%Objective:To observe the changes of N-methyl-D-aspartate receptor (NMDAR) and α-amino-3-hydroxy-5-methyl-4-isox-Azoleprop-ionic acid receptor (AmPAR) mediated evoked excitatory post synaptic currents(eEPSC)in hippocampal CA1 region of the DCD rat models. To investigate the epi-leptogenic mechanism in rat models of the disorder of cortical development (DCD). Methods: The amplitude and decay time constant of NMDAR and AmPAR mediated eEPSC in hippocampal CA1 region pyramidal neurons of DCD rat models were observed using visual patch clamp whole-cell recording technique when the offspring rats were P10d-P20d. Results, Compared with the control group, the amplitude of NMDAR mediated eEPSC in DCD rat models significantly increased[(119. 54±10. 97) pA vs (83. 69± 10. 23) pA;P0. 05][(47. 23±2. 28) vs (48. 68±2.20),P>0. 05]. Conclusion: The NMDAR mediated hyper excitable synaptic responses could play an important role in epileptogenic mechanism of DCDs rat models.

  6. Changes in the axonal conduction velocity of pyramidal tract neurons in the aged cat.

    Science.gov (United States)

    Xi, M C; Liu, R H; Engelhardt, J K; Morales, F R; Chase, M H

    1999-01-01

    The present study was undertaken to determine whether age-dependent changes in axonal conduction velocity occur in pyramidal tract neurons. A total of 260 and 254 pyramidal tract neurons were recorded extracellularly in the motor cortex of adult control and aged cats, respectively. These cells were activated antidromically by electrical stimulation of the medullary pyramidal tract. Fast- and slow-conducting neurons were identified according to their axonal conduction velocity in both control and aged cats. While 51% of pyramidal tract neurons recorded in the control cats were fast conducting (conduction velocity greater than 20 m/s), only 26% of pyramidal tract neurons in the aged cats were fast conducting. There was a 43% decrease in the median conduction velocity for the entire population of pyramidal tract neurons in aged cats when compared with that of pyramidal tract neurons in the control cats (P cats. However, the regression slope was significantly reduced in aged cats. This reduction was due to the appearance of a group of pyramidal tract neurons with relatively shorter spike durations but slower axonal conduction velocities in the aged cat. Sample intracellular data confirmed the above results. These observations form the basis for the following conclusions: (i) there is a decrease in median conduction velocity of pyramidal tract neurons in aged cats; (ii) the reduction in the axonal conduction velocity of pyramidal tract neurons in aged cats is due, in part, to fibers that previously belonged to the fast-conducting group and now conduct at slower velocity. PMID:10392844

  7. Association of Rgs7/Gβ5 complexes with Girk channels and GABAB receptors in hippocampal CA1 pyramidal neurons

    OpenAIRE

    Fajardo-Serrano, Ana; Wydeven, Nicole; Young, Daniele; Watanabe, Masahiko; Shigemoto, Ryuichi; Martemyanov, Kirill A; Wickman, Kevin; Luján, Rafael

    2013-01-01

    In the hippocampus, signalling through G protein-coupled receptors is modulated by Regulators of G protein Signalling (Rgs) proteins, which act to stimulate the rate of GTP hydrolysis, and consequently, G protein inactivation. The R7-Rgs subfamily selectively deactivates the Gi/o-class of Gα subunits that mediate the action of several GPCRs. Here, we used co-immunoprecipitation, electrophysiology and immunoelectron microscopy techniques to investigate the formation of macromolecular complexes...

  8. Sulforhodamine 101 induces long-term potentiation of intrinsic excitability and synaptic efficacy in hippocampal CA1 pyramidal neurons

    DEFF Research Database (Denmark)

    Kang, J.; Kang, N.; Yu, Y.;

    2010-01-01

    Sulforhodamine 101 (SR101) has been extensively used for investigation as a specific marker for astroglia in vivo and activity-dependent dye for monitoring regulated exocytosis. Here, we report that SR101 has bioactive effects on neuronal activity. Perfusion of slices with SR101 (1 microM) for 10...

  9. Altered function of hippocampal CA1 pyramidal neurons in the rTg4510 mouse model of tauopathy

    DEFF Research Database (Denmark)

    Dalby, Nils Ole; Volbracht, Christiane; Helboe, Lone;

    2013-01-01

    retention time data, we construct analysis of variance models that describe the relationship between these properties and structural characteristics of the analogs. We show that the mathematical models derived from the training set data can be used to predict the properties of other analogs in the chemical...

  10. TARGET-SPECIFIC OUTPUT PATTERNS CAN BE PREDICTED BY THE DISTRIBUTION OF REGULAR-SPIKING AND BURSTING PYRAMIDAL NEURONS IN THE SUBICULUM

    OpenAIRE

    Kim, Yujin; Spruston, Nelson

    2011-01-01

    Pyramidal neurons in the subiculum project to a variety of cortical and subcortical areas in the brain to convey information processed in hippocampus. Previous studies have shown that two groups of subicular pyramidal neurons – regular-spiking and bursting neurons – are distributed in an organized fashion along the proximal-distal axis, with more regular-spiking neurons close to CA1 (proximal) and more bursting neurons close to presubiculum (distal). Anatomically, neurons projecting to some t...

  11. Effects of citalopram on expression of B-cell lyraphoma/leukemia-2 and Bcl-associated X protein and neuron apoptosis in hippocmnpus CA1 and CA3 regions of long-term stress rats%西酞普兰对慢性应激大鼠海马CA1和CA3区神经细胞B细胞淋巴瘤/白血病-2及Bcl相关蛋白表达与凋亡的影响

    Institute of Scientific and Technical Information of China (English)

    俞爱月; 苏巧荣; 刘学红; 王岚; 张剑

    2009-01-01

    Objective To explore effects of citalopram on preventing neuron apoptosis in CA1 and CA3 regions of hippocampus in chronic stress rats.Methods Forty male Sprague Dawley rats were randomly divided into five groups with eight each group.Stressed rat models were made by forced swimming daily for 4 weeks,and the stressed group wag treated with intragagtric administration of 0.9% sodium chloride,and three experimental groups with different dosage of citalopram.The fifth group was given no treatment as control.The proteins of bcl-2 and bax were detected with immunohistochemistry.Apoptosis cell number and integral optical density in CA1 and CA3 regions were tested and analyzed with terminal deoxynucleotidyl transferage biotin-dUTP nick end labeling(TUNEL)method and Nikon imaging software-BR(NIS-BR).Results The stationary time Wag longer in the stress group[(279±53)s]than the control group[(182 ±35)s],and the three citalopram treatment group[(200±71)s,(159±59)s,(165±54)s].The number of struggling[(20 ±3)times]was less than control group[(24 ±3)times]and the treatment groups[(37 ±16),(32 ±10),(24 ±4)times],and exhaustive time[(38.3 ±5.1)min]longer than control group[(22.9±1.8)min],shorter than treatment groups[(54.4 ±2.9)min,(69.3±17.6)min,(46.4±4.0)min].AlJ tIle differences were statistically significant(P<0.05 or 0.01).Rats in the stress group showed more apoptotic cells,reduced expression of bcl-2 and increased bax protein expression in CA1 and CA3 regions(P<0.05 or 0.01)in comparison with control group.Compared to the stressed group,rats in treatment groups showed Iess apoptotic cells,reduced expression of bax and increased bcl-2 protein expression in CA1 and CA3 regions(P<0.05).Conclusion Long-term stress might cause neuron apoptosis and expression of bcl-2 and bax in CA1 and CA3 region of hippocampus,and citalopram might have prophylactic effects on this process.%目的 探讨西酞普兰对慢性应激大鼠海马CA1、CA3神经

  12. Pyramid Lake Task Force : Final report

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Pyramid Lake Task Force was created to address Pyramid Lake’s recession and recommend possible solutions that would consider both the needs for preserving the...

  13. Contains and Inside relationships within combinatorial Pyramids

    OpenAIRE

    Brun, Luc; Kropatsch, Walter

    2007-01-01

    Irregular pyramids are made of a stack of successively reduced graphs embedded in the plane. Such pyramids are used within the segmentation framework to encode a hierarchy of partitions. The different graph models used within the irregular pyramid framework encode different types of relationships between regions. This paper compares different graph models used within the irregular pyramid framework according to a set of relationships between regions. We also define a new algorithm based on a ...

  14. Fabrication of nanopore on pyramid

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Seong Soo, E-mail: sscphy2010@gmail.com [Department of Nanoscience and Instrument Center, SunMoon University, Ahsan 336-708 (Korea, Republic of); Park, Myong-Jin; Yamaguchi, Tokutaro [Department of Nanoscience and Instrument Center, SunMoon University, Ahsan 336-708 (Korea, Republic of); Kim, Sung-In; Park, Kyung-Jin [Team for Measurement and Analysis, National Nanofab Center, Daejeon 305-806 (Korea, Republic of); Park, Nam Kyoo [School of Electrical Engineering, Seoul National University, Seoul (Korea, Republic of)

    2014-08-15

    Graphical abstract: - Highlights: • Au nanopores on the apex of the pyramidal structure were fabricated. • The nanopore formations dependent upon the electron currents, the primary electron voltage, and the scan rate were examined. • Nanopore formation using focused ion beam was also investigated. - Abstract: There have been tremendous interests about the fabrication of metallic nanopore due to the ultrafast genome sequencing biosensor capability. In this report, the fabrication of the nanopore on the Au coated SiO{sub 2} pyramid has been examined using various high energy electron beam irradiation and focused ion beam (FIB) milling techniques. The microfabricated Au nano-apertures on pyramid were irradiated with various high energy electron beam and FIB techniques. The formation of the nanopore dependent on the probe current was also examined using electron probe micro-analysis (EPMA). The nanopore on the Au coated SiO{sub 2} pyramid is found to be an Au-Si mixture. The Au nanopore on the crater type hole was also fabricated using FIB Ga ion beam scanning. The shrinking rate was found to be the fastest compared with those fabricated with the other electron beam techniques.

  15. The Base of the Pyramid

    NARCIS (Netherlands)

    Hutte, E.; Vermeulen, P.A.M.

    2014-01-01

    This chapter provides a brief background to the Base of the Pyramid (BoP) phenomenon. It begins with a discussion on what sets the BoP markets apart from more traditional markets and why companies have not identified them as a business opportunity. The chapter then provides an overview of how attent

  16. A magic pyramid of supergravities

    Science.gov (United States)

    Anastasiou, A.; Borsten, L.; Duff, M. J.; Hughes, L. J.; Nagy, S.

    2014-04-01

    By formulating = 1, 2, 4, 8, D = 3, Yang-Mills with a single Lagrangian and single set of transformation rules, but with fields valued respectively in , it was recently shown that tensoring left and right multiplets yields a Freudenthal-Rosenfeld-Tits magic square of D = 3 supergravities. This was subsequently tied in with the more familiar description of spacetime to give a unified division-algebraic description of extended super Yang-Mills in D = 3, 4, 6, 10. Here, these constructions are brought together resulting in a magic pyramid of supergravities. The base of the pyramid in D = 3 is the known 4 × 4 magic square, while the higher levels are comprised of a 3 × 3 square in D = 4, a 2 × 2 square in D = 6 and Type II supergravity at the apex in D = 10. The corresponding U-duality groups are given by a new algebraic structure, the magic pyramid formula, which may be regarded as being defined over three division algebras, one for spacetime and each of the left/right Yang-Mills multiplets. We also construct a conformal magic pyramid by tensoring conformal supermultiplets in D = 3, 4, 6. The missing entry in D = 10 is suggestive of anexotic theory with G/ H duality structure F 4(4)/Sp(3) × Sp(1).

  17. The Chinese Pyramids and the Sun

    CERN Document Server

    Sparavigna, Amelia Carolina

    2012-01-01

    The Chinese Pyramids are huge ancient burial mounds. In the satellite images we can see some complexes where the main buildings are the pyramidal mounds of an emperor and his empress. Here we discuss a possible sunrise/sunset orientation of these two pyramids on the solstices and equinoxes.

  18. Investigation of the Great Pyramid of Giza.

    Science.gov (United States)

    Peace, Nigel; And Others

    1997-01-01

    Describes an activity in which geometry and trigonometry are studied using pyramids. Identical model pyramids are constructed from card stock, along with pyramids of different proportions and cuboids to use as controls. Also includes an investigation of some apparently non-scientific claims. (DDR)

  19. Three Types of Network Complexity Pyramid

    Institute of Scientific and Technical Information of China (English)

    FANG; Jin-qing; LI; Yong; LIU; Qiang

    2012-01-01

    <正>Exploring the complexity and diversity of complex networks have been very challenging issues in network science and engineering. Among them exploring the network complexity pyramids (NCP) are one of important expressions in network complexity. So far as we have proposed the three types of the network complexity pyramid (NCP). The first type of NCP is the network model complexity pyramid with

  20. Prenatal nicotine and maternal deprivation stress de-regulate the development of CA1, CA3, and dentate gyrus neurons in hippocampus of infant rats.

    Directory of Open Access Journals (Sweden)

    Hong Wang

    Full Text Available Adverse experiences by the developing fetus and in early childhood are associated with profound effects on learning, emotional behavior, and cognition as a whole. In this study we investigated the effects of prenatal nicotine exposure (NIC, postnatal maternal deprivation (MD or the combination of the two (NIC+MD to determine if hippocampal neuron development is modulated by exposure to drugs of abuse and/or stress. Growth of rat offspring exposed to MD alone or NIC+MD was repressed until after weaning. In CA1 but not CA3 of postnatal day 14 (P14 pups, MD increased pyramidal neurons, however, in dentate gyrus (DG, decreased granule neurons. NIC had no effect on neuron number in CA1, CA3 or DG. Unexpectedly, NIC plus MD combined caused a synergistic increase in the number of CA1 or CA3 neurons. Neuron density in CA regions was unaffected by treatment, but in the DG, granule neurons had a looser packing density after NIC, MD or NIC+MD exposure. When septotemporal axes were analyzed, the synergism of stress and drug exposure in CA1 and CA3 was associated with rostral, whereas MD effects were predominantly associated with caudal neurons. TUNEL labeling suggests no active apoptosis at P14, and doublecortin positive neurons and mossy fibers were diminished in NIC+MD relative to controls. The laterality of the effect of nicotine and/or maternal deprivation in right versus left hippocampus was also analyzed and found to be insiginificant. We report for the first time that early life stressors such as postnatal MD and prenatal NIC exposure, when combined, may exhibit synergistic consequences for CA1 and CA3 pyramidal neuron development, and a potential antagonistic influence on developing DG neurons. These results suggest that early stressors may modulate neurogenesis, apoptosis, or maturation of glutamatergic neurons in the hippocampus in a region-specific manner during critical periods of neurodevelopment.

  1. Identification and two-photon imaging of oligodendrocyte in CA1 region of hippocampal slices

    International Nuclear Information System (INIS)

    Oligodendrocyte (OL) plays a critical role in myelination and axon maintenance in central nervous system. Recent studies show that OL can also express NMDA receptors in development and pathological situations in white matter. There is still lack of studies about OL properties and function in gray matter of brain. Here we reported that some glial cells in CA1 region of rat hippocampal slices (P15-23) had distinct electrophysiological characteristics from the other glia cells in this region, while they displayed uniform properties with OL from white matter in previous report; therefore, they were considered as OL in hippocampus. By loading dye in recording pipette and imaging with two-photon laser scanning microscopy, we acquired the high spatial resolution, three-dimension images of these special cells in live slices. The OL in hippocampus shows a complex process-bearing shape and the distribution of several processes is parallel to Schaffer fiber in CA1 region. When stimulating Schaffer fiber, OL displays a long duration depolarization mediated by inward rectifier potassium channel. This suggested that the OL in CA1 region could sense the neuronal activity and contribute to potassium clearance

  2. Cellular Mechanisms Underlying Hippocampal CA1 Place Cell Activity

    OpenAIRE

    Fallahnezhad, Mehdi

    2015-01-01

    Norsk Sammendrag: Nerveceller er de grunnleggende byggesteinene i hjernen hos pattedyr og deres aktivitet fører til hjernefunksjoner. Aktivitetsmønsteret til en nervecelle, slik som det romlige fyringsmønsteret laget av en stedcelle i hippocampus, oppstår gjennom samspillet mellom inngangsaktiviteten fra presynaptiske nerveceller og de molekylære mekanismene i nervecellen (cellulær mekanisme). Til tross for omfattende karakterisering av stedcelleaktivitet er ikke de underligge...

  3. Quantile pyramids for Bayesian nonparametrics

    OpenAIRE

    2009-01-01

    P\\'{o}lya trees fix partitions and use random probabilities in order to construct random probability measures. With quantile pyramids we instead fix probabilities and use random partitions. For nonparametric Bayesian inference we use a prior which supports piecewise linear quantile functions, based on the need to work with a finite set of partitions, yet we show that the limiting version of the prior exists. We also discuss and investigate an alternative model based on the so-called substitut...

  4. LBP and irregular graph pyramids

    OpenAIRE

    Cerman, Martin; González Díaz, Rocío; Kropatsch, Walter

    2015-01-01

    In this paper, a new codification of Local Binary Patterns (LBP) is given using graph pyramids. The LBP code characterizes the topological category (local max, min, slope, saddle) of the gray level landscape around the center region. Given a 2D grayscale image I, our goal is to obtain a simplified image which can be seen as “minimal” representation in terms of topological characterization of I. For this, a method is developed based on merging regions and Minimum Contrast Algorithm.

  5. Pyramidal parent training by peers.

    OpenAIRE

    Neef, N A

    1995-01-01

    This study replicated a pyramidal model of parent training by peers and compared its effects with training by a professional with 26 parents of children with disabilities. A multiple probe design across 3 tiers of parents showed that both types of training produced acquisition, maintenance, and to varying extents, generalization of parents' teaching skills, with concomitant increases in the children's performance in most cases. Improvements were comparable for parents trained by a professiona...

  6. A magic pyramid of supergravities

    CERN Document Server

    Anastasiou, A; Duff, M J; Hughes, L J; Nagy, S

    2013-01-01

    By formulating N = 1, 2, 4, 8, D = 3, Yang-Mills with a single Lagrangian and single set of transformation rules, but with fields valued respectively in R,C,H,O, it was recently shown that tensoring left and right multiplets yields a Freudenthal-Rosenfeld-Tits magic square of D = 3 supergravities. This was subsequently tied in with the more familiar R,C,H,O description of spacetime to give a unified division-algebraic description of extended super Yang-Mills in D = 3, 4, 6, 10. Here, these constructions are brought together resulting in a magic pyramid of supergravities. The base of the pyramid in D = 3 is the known 4x4 magic square, while the higher levels are comprised of a 3x3 square in D = 4, a 2x2 square in D = 6 and Type II supergravity at the apex in D = 10. The corresponding U-duality groups are given by a new algebraic structure, the magic pyramid formula, which may be regarded as being defined over three division algebras, one for spacetime and each of the left/right Yang-Mills multiplets. We also c...

  7. Exercise preconditioning exhibits neuroprotective effects on hippocampal CA1 neuronal damage after cerebral ischemia

    Directory of Open Access Journals (Sweden)

    Nabi Shamsaei

    2015-01-01

    Full Text Available Recent evidence has suggested the neuroprotective effects of physical exercise on cerebral ischemic injury. However, the role of physical exercise in cerebral ischemia-induced hippocampal damage remains controversial. The aim of the present study was to evaluate the effects of pre-ischemia treadmill training on hippocampal CA1 neuronal damage after cerebral ischemia. Male adult rats were randomly divided into control, ischemia and exercise + ischemia groups. In the exercise + ischemia group, rats were subjected to running on a treadmill in a designated time schedule (5 days per week for 4 weeks. Then rats underwent cerebral ischemia induction through occlusion of common carotids followed by reperfusion. At 4 days after cerebral ischemia, rat learning and memory abilities were evaluated using passive avoidance memory test and rat hippocampal neuronal damage was detected using Nissl and TUNEL staining. Pre-ischemic exercise significantly reduced the number of TUNEL-positive cells and necrotic cell death in the hippocampal CA1 region as compared to the ischemia group. Moreover, pre-ischemic exercise significantly prevented ischemia-induced memory dysfunction. Pre-ischemic exercise mighct prevent memory deficits after cerebral ischemia through rescuing hippocampal CA1 neurons from ischemia-induced degeneration.

  8. Exercise preconditioning exhibits neuroprotective effects on hippocampal CA1 neuronal damage after cerebral ischemia

    Institute of Scientific and Technical Information of China (English)

    Nabi Shamsaei; Mehdi Khaksari; Sohaila Erfani; Hamid Rajabi; Nahid Aboutaleb

    2015-01-01

    Recent evidence has suggested the neuroprotective effects of physical exercise on cerebral isch-emic injury. However, the role of physical exercise in cerebral ischemia-induced hippocampal damage remains controversial. The aim of the present study was to evaluate the effects of pre-ischemia treadmill training on hippocampal CA1 neuronal damage after cerebral ischemia. Male adult rats were randomly divided into control, ischemia and exercise + ischemia groups. In the exercise + ischemia group, rats were subjected to running on a treadmill in a designated time schedule (5 days per week for 4 weeks). Then rats underwent cerebral ischemia induction th rough occlusion of common carotids followed by reperfusion. At 4 days after cerebral ischemia, rat learning and memory abilities were evaluated using passive avoidance memory test and rat hippocampal neuronal damage was detected using Nissl and TUNEL staining. Pre-ischemic ex-ercise signiifcantly reduced the number of TUNEL-positive cells and necrotic cell death in the hippocampal CA1 region as compared to the ischemia group. Moreover, pre-ischemic exercise significantly prevented ischemia-induced memory dysfunction. Pre-ischemic exercise mighct prevent memory deficits after cerebral ischemia through rescuing hippocampal CA1 neurons from ischemia-induced degeneration.

  9. Altered spatial arrangement of layer V pyramidal cells in the mouse brain following prenatal low-dose X-irradiation. A stereological study using a novel three-dimensional analysis method to estimate the nearest neighbor distance distributions of cells in thick sections.

    Science.gov (United States)

    Schmitz, Christoph; Grolms, Norman; Hof, Patrick R; Boehringer, Robert; Glaser, Jacob; Korr, Hubert

    2002-09-01

    Prenatal X-irradiation, even at doses gallocyanin. Approximately 700 layer V pyramidal cells per animal were sampled in a systematic-random manner in the middle of the section's thickness. The x-y-z coordinates of these 'parent neurons' were recorded, as well as of all neighboring (up to 10) 'offspring neurons' close to each 'parent neuron'. From these data, the nearest neighbor distance (NND) distributions for layer V pyramidal cells were calculated. Using this novel 3D analysis method, we found that, in comparison to controls, prenatal X-irradiation had no effect on the total neuron number, but did cause a reduction in the mean volume of layer V by 26.5% and a more dispersed spatial arrangement of these neurons. Considering the recent literature, it seems reasonable to consider abnormal neuronal migration as the potential basic cause of this finding. PMID:12183394

  10. Effects of ketamine and midazolam on morphology of dendritic spines in hippocampal CA1 region of neonatal mice

    Institute of Scientific and Technical Information of China (English)

    TAN Hong; REN Rong-rong; XIONG Zhi-qi; WANG Ying-wei

    2009-01-01

    Background It is a common phenomenon that children experience multiple general anesthesias in clinical practice, which raises the question whether repeated exposure to general anesthetics would interfere with the development of the central nervous system of children. The present study was designed to evaluate the effects of repeated treatment with ketamine or midazolam on postnatal dendrite development by examining the morphology of the dendritic spines of the pyramidal neurons in the hippocampal CA1 region in mice.Methods The transgenic green fluorescent protein-M line (GFP-M) mice were used in this study. Ketamine (100 mg/kg), midazolam (50 mg/kg) or saline (10 ml/kg) was administered intraperitoneally once a day on consecutive days from postnatal day 8 (P8) to postnatal day 12 (P12). At postnatal day 13 (P13) and postnatal day 30 (P30), the density and length of the apical dendritic spines of the pyramidal neurons in the hippocampal CA1 region were examined under a confocal microscope.Results At P13, for both the ketamine group and the midazolam group, the dendritic spines were found with a comparatively lower density and longer average length than in the control group. At P30, no significant difference in the density or average length of dendritic spines was found between the anesthetic group and control group.Conclusions This study indicated that repeated exposure to ketamine or midazolam in neonatal mice impaired dendritic spine maturation immediately afterwards, but this influence seemed to disappear during further postnatal development.

  11. 糖尿病小鼠学习记忆能力减退与海马锥体细胞树突棘变化的相关性%Diabetes mellitus induced impairment of memory associated with the changes of dendritical spine of pyramid cell in hippocampus

    Institute of Scientific and Technical Information of China (English)

    吕丹丹; 尹洁; 穆继英; 景玉宏

    2012-01-01

    目的 探讨代谢异常导致的海马区树突棘变化与认知功能障碍的关系.方法 通过水迷宫实验检测动物学习记忆变化,通过Gol-gi-Cox染色结合体视学半定量技术分析海马CAl区锥体细胞树突棘密度变化.结果 2型糖尿病(T2DM)小鼠在一个月出现胰岛索抵抗,并伴随持续的高血糖及高胆固醇血症.2个月出现学习记忆能力下降(P<0.05),随时间延长而加重,4个月后海马CA1区锥体细胞树突棘密度显著下降(P<0.01).结论 研究结果表明T2DM持续高血糖,高血脂可能直接导致海马区神经细胞树突棘丢失,突触可塑性下降,从而出现认知功能障碍.%Objective To explore the roles of dendritical spine of pyramid cell in hippocampus on impairment of cognition under the condition of untreated-diabetes mellitus. Methods Learning and memory were tested by Morris water maze, and dendritical spines were observed by Golgi-Cox-staining. Stereological methods were used to quantitate the density of dendritical spine. Results The diabetic mice presented the insensitivity of insulin in fast at one month, accompanied the last hyperglycemia and hyperlipidemia. Diabetes caused the decline of cognition at two or four months in diabetic mice( P < 0. 05 ). Density of dendritical spine of hippocampus was significantly decreased in diabetic mice compared with that of control group (P < 0. 01). Conclusions Persistent high glucose and cholesterol in diabetic mice can lead to the lose of dendritical spine of hippocampus and the decreasing of synaptic plasticity, which can result in the impairment of memory.

  12. Neutron diffraction studies on Ca1-BaZr4P6O24 solid solutions

    Indian Academy of Sciences (India)

    S N Achary; O D Jayakumar; S J Patwe; A B Shinde; P S R Krishna; S K Kulshreshtha; A K Tyagi

    2008-11-01

    Herein we report the results of detailed crystallographic studies of Ca1-BaZr4P6O24 compositions from combined Rietveld refinements of powder X-ray and neutron diffraction data. All the studied compositions crystallize in rhombohedral lattice (space group R-3 No. 148). A continuous solid solution is concluded from the systematic variation of unit cell parameters. The variation of unit cell parameters with the composition indicates decreasing trend in parameter with increasing Ba2+ concentration contrast to an increasing trend in parameter.

  13. An Analysis of Pyramidal Image Fusion Techniques

    OpenAIRE

    Meek, T. R.

    1999-01-01

    This paper discusses the application of multiresolution image fusion techniques to synthetic aperture radar (SAR) and Landsat imagery. Results were acquired through the development and application of image fusion software to test images. The test images were fused using six image fusion techniques that are the combinations from three types of image decomposition algorithms (ratio of low pass [RoLP] pyramids, gradient pyramids, and morphological pyramids) and two types of fusion algorithms (se...

  14. Inside and outside within combinatorial pyramids

    OpenAIRE

    Brun, Luc; Kropatsch, Walter G.

    2005-01-01

    Irregular pyramids are made of a stack of successively reduced graphs embedded in the plane. Such pyramids are often used within the segmentation and the connected component analysis frameworks to detect meaningful objects together with their spatial and topological relationships. The graphs reduced in the pyramid may be region adjacency graphs, dual graphs or combinatorial maps. Using any of these graphs each vertex of a reduced graph encodes a region of the image. Using simple graphs one ed...

  15. Multichannel Texture Segmentation Using Bamberger Pyramids

    OpenAIRE

    Smith, Mark J.T.; Jose Gerardo Rosiles

    2009-01-01

    Abstract A multichannel texture segmentation algorithm is presented based on the image pyramids produced with the Bamberger directional filter bank. An extensive evaluation of Bamberger pyramids and their design parameters is presented. The impact on segmentation performance of factors like the number of pyramid levels, number of directional channels, redundancy and filter specifications is considered. The proposed system is shown to provide some of the best results reported to date when comp...

  16. The Emergence of Corporate Pyramids in China

    OpenAIRE

    Fan, Joseph P.H.; T.J. Wong; Zhang, Tianyu

    2006-01-01

    We examine the pyramidal ownership structure of a large sample of newly listed Chinese companies controlled by local governments or private entrepreneurs. Both types of the owners use layers of intermediate companies to control their firms. However, their pyramiding behaviors are likely affected by different property rights constraints. Local governments are constrained by the Chinese laws prohibiting free transfer of state ownership. Pyramiding allows them to credibly decentralize their firm...

  17. Modulators of cytoskeletal reorganization in CA1 hippocampal neurons show increased expression in patients at mid-stage Alzheimer's disease.

    Directory of Open Access Journals (Sweden)

    Patricia F Kao

    Full Text Available During the progression of Alzheimer's disease (AD, hippocampal neurons undergo cytoskeletal reorganization, resulting in degenerative as well as regenerative changes. As neurofibrillary tangles form and dystrophic neurites appear, sprouting neuronal processes with growth cones emerge. Actin and tubulin are indispensable for normal neurite development and regenerative responses to injury and neurodegenerative stimuli. We have previously shown that actin capping protein beta2 subunit, Capzb2, binds tubulin and, in the presence of tau, affects microtubule polymerization necessary for neurite outgrowth and normal growth cone morphology. Accordingly, Capzb2 silencing in hippocampal neurons resulted in short, dystrophic neurites, seen in neurodegenerative diseases including AD. Here we demonstrate the statistically significant increase in the Capzb2 expression in the postmortem hippocampi in persons at mid-stage, Braak and Braak stage (BB III-IV, non-familial AD in comparison to controls. The dynamics of Capzb2 expression in progressive AD stages cannot be attributed to reactive astrocytosis. Moreover, the increased expression of Capzb2 mRNA in CA1 pyramidal neurons in AD BB III-IV is accompanied by an increased mRNA expression of brain derived neurotrophic factor (BDNF receptor tyrosine kinase B (TrkB, mediator of synaptic plasticity in hippocampal neurons. Thus, the up-regulation of Capzb2 and TrkB may reflect cytoskeletal reorganization and/or regenerative response occurring in hippocampal CA1 neurons at a specific stage of AD progression.

  18. Back-propagation of physiological action potential output in dendrites of slender-tufted L5A pyramidal neurons

    OpenAIRE

    Grewe, Benjamin F.; Audrey Bonnan; Andreas Frick

    2010-01-01

    Pyramidal neurons of layer 5A are a major neocortical output type and clearly distinguished from layer 5B pyramidal neurons with respect to morphology, in vivo firing patterns, and connectivity; yet knowledge of their dendritic properties is scant. We used a combination of whole-cell recordings and Ca2+ imaging techniques in vitro to explore the specific dendritic signalling role of physiological action potential patterns recorded in vivo in layer 5A pyramidal neurons of the whisker-related &...

  19. Deciphering the Role of CA1 Inhibitory Circuits in Sharp Wave-Ripple Complexes

    Directory of Open Access Journals (Sweden)

    Jiannis Taxidis

    2013-05-01

    Full Text Available Sharp wave-ripples (SWRs are population oscillatory patterns in hippocampal LFPs during deep sleep and immobility, involved in the replay of memories acquired during wakefulness. SWRs have been extensively studied, but their exact generation mechanism is still unknown. A computational model has suggested that fast perisomatic inhibition may generate the high frequency ripples (~200 Hz. Another model showed how replay of memories can be controlled by various classes of inhibitory interneurons targeting specific parts of pyramidal cells (PC and firing at particular SWR phases. Optogenetic studies revealed new roles for interneuronal classes and rich dynamic interplays between them, shedding new light in their potential role in SWRs. Here, we integrate these findings in a conceptual model of how dendritic and somatic inhibition may collectively contribute to the SWR generation. We suggest that sharp wave excitation and basket cell (BC recurrent inhibition synchronises BC spiking in ripple frequencies. This rhythm is imposed on bistratified cells which prevent pyramidal bursting. Axo-axonic and stratum lacunosum/moleculare interneurons are silenced by inhibitory inputs originating in the medial septum. PCs receiving rippling inhib

  20. Urban Public Health: Is There a Pyramid?

    Directory of Open Access Journals (Sweden)

    Meirong Su

    2013-01-01

    Full Text Available Early ecologists identified a pyramidal trophic structure in terms of number, biomass and energy transfer. In 1943, the psychologist Maslow put forward a pyramid model to describe layers of human needs. It is indicated that the pyramid principle is universally applicable in natural, humanistic and social disciplines. Here, we report that a pyramid structure also exists in urban public health (UPH. Based on 18 indicators, the UPH states of four cities (Beijing, Tokyo, New York, and London are compared from the point of view of five aspects, namely physical health, living conditions, social security, environmental quality, and education and culture. A pyramid structure was found in each city when focusing on 2000–2009 data. The pyramid of Beijing is relatively similar to that of Tokyo, and the pyramids of New York and London are similar to each other. A general development trend in UPH is proposed and represented by different pyramid modes. As a basic conjecture, the UPH pyramid model can be verified and developed with data of more cities over a longer period, and be used to promote healthy urban development.

  1. Update on the Pyramid Scheme

    CERN Document Server

    Banks, Tom

    2012-01-01

    We summarize recent work in which we attempt to make a consistent model of LHC physics, from the Pyramid Scheme. The models share much with the NMSSM, in particular, enhanced tree level contributions to the Higgs mass and a preference for small tan {\\beta}. There are 3 different singlet fields, and a new strongly coupled gauge theory, so the constraints of perturbative unification are quite different. We outline our general approach to the model, which contains a Kahler potential for three of the low energy fields, which is hard to calculate. Detailed calculations, based on approximations to the Kahler potential, will be presented in a future publication.

  2. The cradle of pyramids in satellite images

    OpenAIRE

    Sparavigna, Amelia Carolina

    2011-01-01

    We propose the use of image processing to enhance the Google Maps of some archaeological areas of Egypt. In particular we analyse that place which is considered the cradle of pyramids, where it was announced the discovery of a new pyramid by means of an infrared remote sensing.

  3. Changes in rat hippocampal CA1 synapses following imipramine treatment

    DEFF Research Database (Denmark)

    Chen, Fenghua; Madsen, Torsten M; Wegener, Gregers;

    2008-01-01

    synapses) in subregions of the hippocampus by quantifying number of neurons and synapses. Adult male Sprague-Dawley rats were injected with imipramine or saline (i.p.) daily for 14 days. Unbiased stereological methods were used to quantify the number of neurons and synapses. No differences in the volume...... and number of neurons of hippocampal subregions following imipramine treatment were found. However, the number and percentage of CA1 asymmetric spine synapses increased significantly and, conversely, the percentage of asymmetric shaft synapses significantly decreased in the imipramine treated group....... Our results indicate that administration of imipramine for 14 days in normal rats could significantly increase the excitatory spine synapses, and change the relative distribution of spine and shaft synapses. We speculate that the present findings may be explained by the establishment of new synaptic...

  4. The Pyramid Phasing Sensor (PYPS)

    Science.gov (United States)

    Pinna, E.; Quirós-Pacheco­, F.; Esposito, S.; Puglisi, A.; Stefanini, P.

    2008-07-01

    PYPS is the pyramid wavefront sensor for the phasing and alignment of segmented mirrors developed in the framework of the Active Phase Experiment (APE). In this paper we will present the PYPS opto-mechanical design, and report the experimental results obtained in the Arcetri laboratories prior to its integration in the main APE bench. A piston-correction closed loop was performed under the presence of emulated turbulence (D/r0=33 @ 700nm and V/D=1.9Hz), achieving a final piston error of 10 nm rms in wavefront. Two filtering techniques were developed to average out faster the atmospheric disturbance reducing the required co-phasing time by two orders of magnitude. We will also present the first experimental results obtained with a synthetic interaction matrix attaining a final piston error of the same order of magnitude.

  5. Space and time sequence and mosaicism of neurogenesis in hippocampal area CA1 in mice

    International Nuclear Information System (INIS)

    The study of the times and sequence of neuron formation in various structures of the mammalian brain has made substantial progress thanks to the use of autoradiographic techniques, by which the germinative precursors of neurons can be tagged with tritium-thymidine and the subsequent fate of the labeled cells can be followed. The authors study the space and time sequence of neuron formation and look for the presence of mosaicism of neurogenesis in area CA1 of Ammon's horn of the mouse hippocampus, one of the most regularly arranged hippocampal areas. An analysis of the distribution of intensively labeled neurons in areas CA1 showed the presence of groups of intensively labeled neurons alternating with unlabeled and weakly labeled cells.. Mice receiving tritium-thymidine on the 13th-16th day of embryogenesis were most marked when the isotope was injected on the 14th-15th day of embroygeneisis. The investigation showed that a mosaic pattern of neurogenesis exists in the hippocampus, just as in the neocortex, and it can be regarded as the result of asynchronous production of neurons by local areas of the germinative zone, each of which constructs a radial segment of cortex

  6. Long-term Potentiation at Temporoammonic Path-CA1 Synapses in Freely Moving Rats.

    Science.gov (United States)

    Gonzalez, Jossina; Villarreal, Desiree M; Morales, Isaiah S; Derrick, Brian E

    2016-01-01

    Hippocampal area CA1 receives direct entorhinal layer III input via the temporoammonic path (TAP) and recent studies implicate TAP-CA1 synapses are important for some aspects of hippocampal memory function. Nonetheless, as few studies have examined TAP-CA1 synaptic plasticity in vivo, the induction and longevity of TAP-CA1 long-term potentiation (LTP) has not been fully characterized. We analyzed CA1 responses following stimulation of the medial aspect of the angular bundle and investigated LTP at medial temporoammonic path (mTAP)-CA1 synapses in freely moving rats. We demonstrate monosynaptic mTAP-CA1 responses can be isolated in vivo as evidenced by observations of independent current sinks in the stratum lacunosum moleculare of both areas CA1 and CA3 following angular bundle stimulation. Contrasting prior indications that TAP input rarely elicits CA1 discharge, we observed mTAP-CA1 responses that appeared to contain putative population spikes in 40% of our behaving animals. Theta burst high frequency stimulation of mTAP afferents resulted in an input specific and N-methyl-D-aspartate (NMDA) receptor-dependent LTP of mTAP-CA1 responses in behaving animals. LTP of mTAP-CA1 responses decayed as a function of two exponential decay curves with time constants (τ) of 2.7 and 148 days to decay 63.2% of maximal LTP. In contrast, mTAP-CA1 population spike potentiation longevity demonstrated a τ of 9.6 days. To our knowledge, these studies provide the first description of mTAP-CA1 LTP longevity in vivo. These data indicate TAP input to area CA1 is a physiologically relevant afferent system that displays robust synaptic plasticity. PMID:26903815

  7. Influence of the ratio of surfactant additives on the anisotropic etching process used to make small pyramids for use in solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Chung Ping [Yuan Ze University, Chungli, Taiwan (China); Fu Jen University, New Taipei, Taiwan (China); Chang, Ming Wei; Chuang, Chuan Lung [Yuan Ze University, Chungli, Taiwan (China)

    2014-05-15

    This paper focuses on surfactant additives (SA) that are used in alkaline etching of p-type monocrystalline silicon wafers for use in screen-printed silicon solar cells. An Al/p-type Si/ntype SiP/SiN{sub x}/Ag solar cell with an active area of 15.6 cm{sup 2} was fabricated. The highest measured efficiency of the solar cells was 19.24%, which proves that the SA method is highly efficient for fabricating monocrystalline silicon solar cells. The results show that 0.4 L of SA is the most favorable volume for alkaline etching of solar-cell samples. Samples etched at this volume exhibit the lowest average reflectance of 0.596%, an average internal quantum efficiency (IQE) gain of 5.6% and an efficiency gain of 0.84%, thus showing the SA method to be an efficient anisotropic etching process. In addition, the cell with the highest efficiency had an increase of 4.57% in power, an increase of 3.1% in the short-circuit current, and an increase of 1.43% in the open-circuit voltage. In summary, microstructural, reflectance, IQE, and I - V measurements revealed that the best cell was formed using an optimal SA volume of 0.4 L.

  8. Local-moment formation and metal–nonmetal transition in Ca1-YVO3 and Ca1-YTiO3

    Indian Academy of Sciences (India)

    Y Nishihara; H Kawanaka; H Bando

    2002-05-01

    Electron-doped metallic states of Ca1-YVO3 and Ca1-YTiO3 change into nonmetallic states around ∼ 0.4 and 0.6, respectively. The residual resistivity in the metallic states increases with increasing effective magnetic moment or coefficient of 2 term of resistivity. The effective moment reaches ∼ 0.5 B/molecule in Ca1-YVO3 and also in Ca1-YTiO3 near the metal–nonmetal phase boundary. In these metallic states, ∼ 10% of 3 atoms seem to have large localized magnetic moments. In electron-doped metallic sample of Ca1-YVO3, the temperature dependence of resistance shows no resistance-minimum. However, weak negative magneto-resistance is observed for the sample with = 0.2 up to 50 Tesla at 4.2 K.

  9. Structural plasticity in hippocampal cells related to the facilitative effect of intracranial self-stimulation on a spatial memory task.

    Science.gov (United States)

    Chamorro-López, Jacobo; Miguéns, Miguel; Morgado-Bernal, Ignacio; Kastanauskaite, Asta; Selvas, Abraham; Cabané-Cucurella, Alberto; Aldavert-Vera, Laura; DeFelipe, Javier; Segura-Torres, Pilar

    2015-12-01

    Posttraining intracranial self-stimulation (SS) in the lateral hypothalamus facilitates the acquisition and retention of several implicit and explicit memory tasks. Here, intracellular injections of Lucifer yellow were used to assess morphological changes in hippocampal neurons that might be specifically related to the facilitative posttraining SS effect upon the acquisition and retention of a distributed spatial task in the Morris water maze. We examined the structure, size and branching complexity of cornus ammonis 1 (CA1) cells, and the spine density of CA1 pyramidal neurons and granular cells of the dentate gyrus (DG). Animals that received SS after each acquisition session performed faster and better than Sham ones--an improvement that was also evident in a probe trial 3 days after the last training session. The neuromorphological analysis revealed an increment in the size and branching complexity in apical CA1 dendritic arborization in SS-treated subjects as compared with Sham animals. Furthermore, increased spine density was observed in the CA1 field in SS animals, whereas no effects were observed in DG cells. Our results support the hypothesis that the facilitating effect of SS on the acquisition and retention of a spatial memory task could be related to structural plasticity in CA1 hippocampal cells. PMID:26501173

  10. FABRIC DEFECT DETECTION USING STEERABLE PYRAMID

    Directory of Open Access Journals (Sweden)

    S. Mythili

    2011-05-01

    Full Text Available In this paper, a novel idea is proposed for fabric defect detection. De- fects are detected in the fabric using steerable pyramid along with a defect detection algorithm. Various steerable pyramid of four size 256*256, 128*128, 64*64, 32*32 and with four orientation bands 00,450, 900, 1350 are used. Utilizing a Steerable pyramid proved ade- quate in the representation of fabric images in multi-scale and multi- orientations; thus allowing defect detection algorithms to run more effectively. Defect detection algorithm identifies and locates the im- perfection in the defective sample using the statistics mean and stan- dard deviation. This statistics represents the relative amount of inten- sity in the texture and is sufficient to measure defects in the current model .The obtained result are compared with the existing methods wavelet based system and with Gaussian and Laplacian pyramid.

  11. Simulation of gene pyramiding in Drosophila melanogaster

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Gene pyramiding has been successfully practiced in plant breeding for developing new breeds or lines in which favorable genes from several different lines were integrated.But it has not been used in animal breeding,and some theoretical investigation and simulation analysis with respect to its strategies,feasibility and efficiency are needed before it can be implemented in animals.In this study,we used four different pure fines of Drosophila melanogaster,each of which is homozygous at a specific mutant gene with a visible effect on phenotype,to simulate the gene pyramiding process and analyze the duration and population size required in different pyramiding strategies.We finally got the ideal individuals,which are homozygous at the four target genes simultaneously.This study demonstrates that gene pyramiding is feasible in animal breeding and the interaction between genes may affect the final results.

  12. Pyramidal micromirrors for microsystems and atom chips

    Science.gov (United States)

    Trupke, M.; Ramirez-Martinez, F.; Curtis, E. A.; Ashmore, J. P.; Eriksson, S.; Hinds, E. A.; Moktadir, Z.; Gollasch, C.; Kraft, M.; Vijaya Prakash, G.; Baumberg, J. J.

    2006-02-01

    Concave pyramids are created in the (100) surface of a silicon wafer by anisotropic etching in potassium hydroxide. High quality micromirrors are then formed by sputtering gold onto the smooth silicon (111) faces of the pyramids. These mirrors show great promise as high quality optical devices suitable for integration into micro-optoelectromechanical systems and atom chips. We have shown that structures of this shape can be used to laser-cool and hold atoms in a magneto-optical trap.

  13. Improvement of polycrystalline silicon wafer solar cell efficiency by forming nanoscale pyramids on wafer surface using a self-mask etching technique

    OpenAIRE

    Lin, Hsin-Han; Chen, Wen-Hwa; Hong, Franklin C.-N.

    2013-01-01

    The creation of nanostructures on polycrystalline silicon wafer surface to reduce the solar reflection can enhance the solar absorption and thus increase the solar-electricity conversion efficiency of solar cells. The self-masking reactive ion etching (RIE) was studied to directly fabricate nanostructures on silicon surface without using a masking process for antireflection purpose. Reactive gases comprising chlorine (Cl2), sulfur hexafluoride (SF6), and oxygen (O2) were activated by radio-fr...

  14. Fluoxetine (prozac) and serotonin act on excitatory synaptic transmission to suppress single layer 2/3 pyramidal neuron-triggered cell assemblies in the human prefrontal cortex.

    OpenAIRE

    Komlosi, G.; Molnar, G.; Rozsa, M.; Olah, S.; Barzo, P.; Tamas, G.

    2012-01-01

    Selective serotonin reuptake inhibitors are the most widely prescribed drugs targeting the CNS with acute and chronic effects in cognitive, emotional and behavioral processes. This suggests that microcircuits of the human cerebral cortex are powerfully modulated by selective serotonin reuptake inhibitors, however, direct measurements of serotonergic regulation on human synaptic interactions are missing. Using multiple whole-cell patch-clamp recordings from neurons in acute cortical slices der...

  15. Enhancement of Hippocampal Pyramidal Cell Excitability by the Novel Selective Slow-Afterhyperpolarization Channel Blocker 3-(Triphenylmethylaminomethyl)pyridine (UCL2077)

    OpenAIRE

    Shah, Mala M.; Javadzadeh-Tabatabaie, Mazyar; Benton, David C H; Ganellin, C. Robin; Haylett, Dennis G.

    2006-01-01

    The slow afterhyperpolarization (sAHP) in hippocampal neurons has been implicated in learning and memory. However, its precise role in cell excitability and central nervous system function has not been explicitly tested for 2 reasons: 1) there are, at present, no selective inhibitors that effectively reduce the underlying current in vivo or in intact in vitro tissue preparations, and 2) although it is known that a small conductance K+ channel that activates after a rise in [Ca2+]i underlies t...

  16. Enhancement of hippocampal pyramidal cell excitability by the novel selective slow-afterhyperpolarization channel blocker 3-(triphenylmethylaminomethyl)pyridine (UCL2077).

    Science.gov (United States)

    Shah, Mala M; Javadzadeh-Tabatabaie, Mazyar; Benton, David C H; Ganellin, C Robin; Haylett, Dennis G

    2006-11-01

    The slow afterhyperpolarization (sAHP) in hippocampal neurons has been implicated in learning and memory. However, its precise role in cell excitability and central nervous system function has not been explicitly tested for 2 reasons: 1) there are, at present, no selective inhibitors that effectively reduce the underlying current in vivo or in intact in vitro tissue preparations, and 2) although it is known that a small conductance K(+) channel that activates after a rise in [Ca(2+)](i) underlies the sAHP, the exact molecular identity remains unknown. We show that 3-(triphenylmethylaminomethyl)pyridine (UCL2077), a novel compound, suppressed the sAHP present in hippocampal neurons in culture (IC(50) = 0.5 microM) and in the slice preparation (IC(50) approximately 10 microM). UCL2077 was selective, having minimal effects on Ca(2+) channels, action potentials, input resistance and the medium afterhyperpolarization. UCL2077 also had little effect on heterologously expressed small conductance Ca(2+)-activated K(+) (SK) channels. Moreover, UCL2077 and apamin, a selective SK channel blocker, affected spike firing in hippocampal neurons in different ways. These results provide further evidence that SK channels are unlikely to underlie the sAHP. This study also demonstrates that UCL2077, the most potent, selective sAHP blocker described so far, is a useful pharmacological tool for exploring the role of sAHP channels in the regulation of cell excitability in intact tissue preparations and, potentially, in vivo. PMID:16877678

  17. Comparative morphology of three types of projection-identified pyramidal neurons in the superficial layers of cat visual cortex.

    Science.gov (United States)

    Matsubara, J A; Chase, R; Thejomayen, M

    1996-02-26

    The morphology and dendritic organization of corticocortical neurons in the superficial layers of area 18 that project to area 17 were studied by intracellular injection of lucifer yellow in the fixed-slice preparation. This corticocortical population contains primarily standard pyramidal cells, but occasional nonpyramidal, modified, fusiform, star, and inverted pyramidal cells were also seen. All cell types were present throughout layer 2 and in the upper and middle parts of layer 3. Standard pyramidal cells were found exclusively in lower layer 3. The mean somatic area of the area 17 projecting neurons was 251 microns 2. The width of basal dendritic fields was correlated to cell size for standard pyramidal cells but not for the other cell types. Next, the morphology and dendritic organization of the area 17 projecting neurons were compared to the pyramidal cells of the local horizontal patch networks and of the callosal system. The depth profile of the area 17 projecting and callosal pyramidal groups was virtually identical, peaking at 400 microns from the pial surface, whereas the local patch pyramidal group peaked at 281 microns. The local patch, area 17 projecting, and callosal pyramidal cells displayed increasingly larger mean somatic areas and basilar dendritic field width measurements. The number of basal dendritic branch points was greatest for callosal cells, and it was indistinguishable between local patch and area 17 projecting neurons. In the tangential plane, circular dendritic fields were observed on all callosal cells, but they were found on only approximately half of the local patch and area 17 projecting neurons. The remaining local patch and area 17 projecting neurons displayed mediolaterally and anteroposteriorly elongated basal dendritic fields, respectively. PMID:8866848

  18. A novel non-CB1/TRPV1 endocannabinoid-mediated mechanism depresses excitatory synapses on hippocampal CA1 interneurons

    OpenAIRE

    Edwards, Jeffrey G.; Gibson, Helen E.; Jensen, Tyron; Nugent, Fereshteh; Walther, Curtis; Blickenstaff, Jacob; Kauer, Julie A.

    2010-01-01

    Endocannabinoids (eCBs) mediate various forms of synaptic plasticity at excitatory and inhibitory synapses in the brain. The eCB anandamide binds to several receptors including the transient receptor potential vanilloid 1 (TRPV1) and cannabinoid receptor 1 (CB1). We recently identified that TRPV1 is required for long-term depression at excitatory synapses on hippocampal stratum radiatum interneurons. Here we performed whole-cell patch clamp recordings from CA1 stratum radiatum interneurons in...

  19. Pascal Pyramids, Pascal Hyper-Pyramids and a Bilateral Multinomial Theorem

    OpenAIRE

    Horn, Martin Erik

    2003-01-01

    Part I: The two-dimensional Pascal Triangle will be generalized into a three-dimensional Pascal Pyramid and four-, five- or whatsoever-dimensional hyper-pyramids. Part II: The Bilateral Binomial Theorem will be generalised into a Bilateral Trinomial Theorem resp. a Bilateral Multinomial Theorem.

  20. 海马电刺激对耐药性颞叶癫痫大鼠CA1区神经元钠通道电流的影响%Effect of hippocampal electrical stimulation on the sodium channel current in CA1 region neurons in rats with pharmacoresistant temporal lobe epilepsy

    Institute of Scientific and Technical Information of China (English)

    伍国锋; 洪震; 高宾丽; 周凤

    2013-01-01

    group) and a pharmacoresistant control group (PR group).A low-frequency hippocampal stimulation was performed in the HS group,while the PR group received sham stimulation.The whole-cell recording technique by patch-clamp was used to observe the changes of sodium current of hippocampal pyramidal neurons after the hippocampal stimulation.Results Compared with the PR group,the pharmacoresistant epileptic rats in HS group underwent low-frequency stimulation for 2 weeks showed that the amygdale stimulus-induced seizures were decreased (2.32 ± 0.38 in HS group and 4.45 ± 0.42 in PR group,t =84.600,P =0.000) and the parameters of the after-discharges were improved significantly.In HS group,the peak current shifted towards depolarization,the sodium channels were difficult to activate,and were more susceptible to inactivation.Moreover,the recovery time after the sodium channel inactivation was slower in HS group ((17.9 ±0.6) s) than in PR group((16.3 +0.3) s,t =-25.420,P =0.000).Conclusions Hippocampal stimulation may inhibit the sodium channel current of pyramidal neurons in CA1 areas of hippocampus.The mechanism of hippocampal stimulation in the treatment of pharmacoresistant epilepsy might be achieved partly by inhibiting the sodium channel current so as to decrease the excitability of hippocampal neurons.

  1. Evaluation of the Ca 1 antibody in the diagnosis of invasive breast cancer.

    OpenAIRE

    Clough, D G; Coghill, G R; Holley, M. P.

    1984-01-01

    An evaluation of Ca 1 antibody staining was performed on paraffin sections from 136 breast lesions (64 benign and 72 malignant). Although cytoplasmic staining was encountered significantly more often in malignant lesions, the false negative rate was 6.9% and the false positive rate 56.2%. Benign lesions which showed positive staining included gynaecomastia, cystic mastopathy and fibroadenomata. Various other monoclonal antibodies showed staining similar to Ca 1 antibody. Ca 1 antibody was obs...

  2. Abelson tyrosine kinase links PDGFbeta receptor activation to cytoskeletal regulation of NMDA receptors in CA1 hippocampal neurons

    Directory of Open Access Journals (Sweden)

    Beazely Michael A

    2008-12-01

    Full Text Available Abstract Background We have previously demonstrated that PDGF receptor activation indirectly inhibits N-methyl-D-aspartate (NMDA currents by modifying the cytoskeleton. PDGF receptor ligand is also neuroprotective in hippocampal slices and cultured neurons. PDGF receptors are tyrosine kinases that control a variety of signal transduction pathways including those mediated by PLCγ. In fibroblasts Src and another non-receptor tyrosine kinase, Abelson kinase (Abl, control PDGF receptor regulation of cytoskeletal dynamics. The mechanism whereby PDGF receptor regulates cytoskeletal dynamics in central neurons remains poorly understood. Results Intracellular applications of active Abl, but not heat-inactivated Abl, decreased NMDA-evoked currents in isolated hippocampal neurons. This mimics the effects of PDGF receptor activation in these neurons. The Abl kinase inhibitor, STI571, blocked the inhibition of NMDA currents by Abl. We demonstrate that PDGF receptors can activate Abl kinase in hippocampal neurons via mechanisms similar to those observed previously in fibroblasts. Furthermore, PDGFβ receptor activation alters the subcellular localization of Abl. Abl kinase is linked to actin cytoskeletal dynamics in many systems. We show that the inhibition of NMDA receptor currents by Abl kinase is blocked by the inclusion of the Rho kinase inhibitor, Y-27632, and that activation of Abl correlates with an increase in ROCK tyrosine phosphorylation. Conclusion This study demonstrates that PDGFβ receptors act via an interaction with Abl kinase and Rho kinase to regulated cytoskeletal regulation of NMDA receptor channels in CA1 pyramidal neurons.

  3. Reactive changes in astrocytes, and delayed neuronal death, in the rat hippocampal CA1 region following cerebral ischemia/reperfusion

    Institute of Scientific and Technical Information of China (English)

    Guiqing Zhang; Xiang Luo; Zhiyuan Yu; Chao Ma; Shabei Xu; Wei Wang

    2009-01-01

    /reperfusion, astrocytes with abnormal morphology were detected in the rat hippocampal CA1 region in the delayed neuronal death (+) subgroup. No significant difference in GFAP expression was found in the rat hippocampal CA1 region at the ischemic hemisphere in the sham operation group, delayed neuronal death (+) subgroup and delayed neuronal death (-) subgroup (P > 0.05). After 7 days of ischemia/reperfusion, many GFAP-positive cells, which possessed a large cell body and an increased number of processes, were activated in the rat hippocampal CA1 region at the ischemic hemisphere. GFAP expression in the hippocampal CA1 region was greater in the delayed neuronal death (+) subgroup and delayed neuronal death (-) subgroup compared with the sham operation group (P 0.05). CONCLUSION: The activation of astrocytes was poor in the hippocampal CA1 region during the early stages of ischemia, which is an important reason for delayed neuronal death. Glial scar formation aggravated delayed neuronal death during the advanced ischemic stage.

  4. Role for MMP-9 in stress-induced downregulation of nectin-3 in hippocampal CA1 and associated behavioural alterations.

    Science.gov (United States)

    van der Kooij, Michael A; Fantin, Martina; Rejmak, Emilia; Grosse, Jocelyn; Zanoletti, Olivia; Fournier, Celine; Ganguly, Krishnendu; Kalita, Katarzyna; Kaczmarek, Leszek; Sandi, Carmen

    2014-01-01

    Chronic stress is a risk factor for the development of psychopathologies characterized by cognitive dysfunction and deregulated social behaviours. Emerging evidence suggests a role for cell adhesion molecules, including nectin-3, in the mechanisms that underlie the behavioural effects of stress. We tested the hypothesis that proteolytic processing of nectins by matrix metalloproteinases (MMPs), an enzyme family that degrades numerous substrates, including cell adhesion molecules, is involved in hippocampal effects induced by chronic restraint stress. A reduction in nectin-3 in the perisynaptic CA1, but not in the CA3, compartment is observed following chronic stress and is implicated in the effects of stress in social exploration, social recognition and a CA1-dependent cognitive task. Increased MMP-9-related gelatinase activity, involving N-methyl-D-aspartate receptor, is specifically found in the CA1 and involved in nectin-3 cleavage and chronic stress-induced social and cognitive alterations. Thus, MMP-9 proteolytic processing emerges as an important mediator of stress effects in brain function and behaviour. PMID:25232752

  5. Tiling a Pyramidal Polycube with Dominoes

    Directory of Open Access Journals (Sweden)

    Olivier Bodini

    2007-05-01

    Full Text Available The notion of pyramidal polycubes, namely the piling-up of bricks of a non-increasing size, generalizes in ℝ n the concept of trapezoidal polyominoes. In the present paper, we prove that n-dimensional dominoes can tile a pyramidal polycube if and only if the latter is balanced, that is, if the number of white cubes is equal to the number of black ones for a chessboard-like coloration, generalizing the result of [BC92] when n=2

  6. Pyramidal central configurations and perverse solutions

    OpenAIRE

    Zhifu Xie; Shiqing Zhang

    2004-01-01

    For $n$-body problems, a central configuration (CC) plays an important role. In this paper, we establish the relation between the spatial pyramidal central configuration (PCC) and the planar central configuration. We prove that the base of PCC is also a CC and we also prove that for some given conditions a planar CC can be extended to a PCC. In particular, if the pyramidal central configuration has a regular polygon base, then the masses of base are equal and the distance between the top vert...

  7. Sulfolobus Turreted Icosahedral Virus c92 Protein Responsible for the Formation of Pyramid-Like Cellular Lysis Structures

    DEFF Research Database (Denmark)

    Snyder, Jamie C; Brumfield, Susan K; Peng, Nan;

    2011-01-01

    Host cells infected by Sulfolobus turreted icosahedral virus (STIV) have been shown to produce unusual pyramid-like structures on the cell surface. These structures represent a virus-induced lysis mechanism that is present in Archaea and appears to be distinct from the holin/endolysin system...... described for DNA bacteriophages. This study investigated the STIV gene products required for pyramid formation in its host Sulfolobus solfataricus. Overexpression of STIV open reading frame (ORF) c92 in S. solfataricus alone is sufficient to produce the pyramid-like lysis structures in cells. Gene...... disruption of c92 within STIV demonstrates that c92 is an essential protein for virus replication. Immunolocalization of c92 shows that the protein is localized to the cellular membranes forming the pyramid-like structures....

  8. Multiresolution maximum intensity volume rendering by morphological adjunction pyramids

    NARCIS (Netherlands)

    Roerdink, Jos B.T.M.

    2003-01-01

    We describe a multiresolution extension to maximum intensity projection (MIP) volume rendering, allowing progressive refinement and perfect reconstruction. The method makes use of morphological adjunction pyramids. The pyramidal analysis and synthesis operators are composed of morphological 3-D eros

  9. The functional genome of CA1 and CA3 neurons under native conditions and in response to ischemia

    Directory of Open Access Journals (Sweden)

    Rossner Moritz

    2007-10-01

    Full Text Available Abstract Background The different physiological repertoire of CA3 and CA1 neurons in the hippocampus, as well as their differing behaviour after noxious stimuli are ultimately based upon differences in the expressed genome. We have compared CA3 and CA1 gene expression in the uninjured brain, and after cerebral ischemia using laser microdissection (LMD, RNA amplification, and array hybridization. Results Profiling in CA1 vs. CA3 under normoxic conditions detected more than 1000 differentially expressed genes that belong to different, physiologically relevant gene ontology groups in both cell types. The comparison of each region under normoxic and ischemic conditions revealed more than 5000 ischemia-regulated genes for each individual cell type. Surprisingly, there was a high co-regulation in both regions. In the ischemic state, only about 100 genes were found to be differentially expressed in CA3 and CA1. The majority of these genes were also different in the native state. A minority of interesting genes (e.g. inhibinbetaA displayed divergent expression preference under native and ischemic conditions with partially opposing directions of regulation in both cell types. Conclusion The differences found in two morphologically very similar cell types situated next to each other in the CNS are large providing a rational basis for physiological differences. Unexpectedly, the genomic response to ischemia is highly similar in these two neuron types, leading to a substantial attenuation of functional genomic differences in these two cell types. Also, the majority of changes that exist in the ischemic state are not generated de novo by the ischemic stimulus, but are preexistant from the genomic repertoire in the native situation. This unexpected influence of a strong noxious stimulus on cell-specific gene expression differences can be explained by the activation of a cell-type independent conserved gene-expression program. Our data generate both novel

  10. A new class of morphological pyramids for multiresolution image analysis

    OpenAIRE

    Roerdink, Jos B. T. M.; Asano, T.; Klette, R; Ronse, C.

    2003-01-01

    We study nonlinear multiresolution signal decomposition based on morphological pyramids. Motivated by a problem arising in multiresolution volume visualization, we introduce a new class of morphological pyramids. In this class the pyramidal synthesis operator always has the same form, i.e. a dilation by a structuring element A, preceded by upsampling, while the pyramidal analysis operator is a certain operator R(n)A indexed by an integer n, followed by downsampling. For n = 0, R(n)A equals th...

  11. Khufu, Khafre and Menkaure Pyramids and the Sun

    CERN Document Server

    Sparavigna, Amelia Carolina

    2016-01-01

    In this paper we discuss the orientation of the Egyptian pyramids at Giza with respect to sunrises and sunsets, using SunCalc.net software. We can see that Khufu and Khafre pyramids had been positioned in a manner that, from each pyramid, it was always possible to observe the points of the horizon where the sun was rising and setting on each day of the year. A discussion for the Menkaure pyramid is also proposed.

  12. State ownership pyramid: extend and control

    Czech Academy of Sciences Publication Activity Database

    Hanousek, Jan; Kočenda, Evžen

    Split : University of Split, Faculty of Economics, 2009, s. 1-25. [International Conference /8./ "Challenges of Europe: Financial Crisis and Climate Change". Split (HR), 21.05.2009-23.05.2009] Institutional research plan: CEZ:AV0Z70850503 Keywords : accounting efficiency * corporate pyramid * state control Subject RIV: AH - Economics

  13. Pyramid Project: An Exemplary Staff Development Plan.

    Science.gov (United States)

    Ardmore City Schools, OK.

    The Ardmore, Oklahoma, School District developed the 3-year Pyramid Project to implement the following recommendations of the Sid W. Richardson Foundation Study of exemplary programs for high ability students: (1) broaden the process for assessing student abilities, (2) adopt continuous progress and appropriate pacing, (3) cultivate students'…

  14. Food Guide Pyramid Becomes a Plate

    Science.gov (United States)

    ... español La pirámide nutricional se convierte en 'Mi plato' Plate = New Symbol for Healthy Eating Goodbye, pyramid. ... a friend Reprint Guidelines Sign up for our free weekly eNewsletters here About KidsHealth About Nemours Contact ...

  15. Ancient Pyramids Help Students Learn Math Concepts

    Science.gov (United States)

    Smith, Courtney D.; Stump, Amanda M.; Lazaros, Edward J.

    2010-01-01

    This article presents an activity that allows students to use mathematics and critical-thinking skills to emulate processes used by the ancient Egyptians to prepare the site for the Pyramids of Giza. To accomplish this, they use three different methods. First, they create a square using only simple technological tools that were available to the…

  16. Teacher Acquisition of Functional Analysis Methods Using Pyramidal Training

    Science.gov (United States)

    Pence, Sacha T.; St. Peter, Claire C.; Giles, Aimee F.

    2014-01-01

    Pyramidal training involves an experienced professional training a subset of individuals who, in turn, train additional individuals. Pyramidal training is effective for training a variety of behavior-analytic skills with direct-care staff, parents, and teachers. As teachers' roles in behavioral assessment increase, pyramidal training may be…

  17. On the astronomical orientation of the IV dynasty Egyptian pyramids and the dating of the second Giza pyramid

    OpenAIRE

    Magli, Giulio

    2003-01-01

    The data on the astronomical orientation of the IV dynasty Egyptian pyramids are re-analyzed and it is shown that such data suggest an inverse chronology between the `first` and the `second` Giza pyramid.

  18. Pyramidal fractal dimension for high resolution images

    Science.gov (United States)

    Mayrhofer-Reinhartshuber, Michael; Ahammer, Helmut

    2016-07-01

    Fractal analysis (FA) should be able to yield reliable and fast results for high-resolution digital images to be applicable in fields that require immediate outcomes. Triggered by an efficient implementation of FA for binary images, we present three new approaches for fractal dimension (D) estimation of images that utilize image pyramids, namely, the pyramid triangular prism, the pyramid gradient, and the pyramid differences method (PTPM, PGM, PDM). We evaluated the performance of the three new and five standard techniques when applied to images with sizes up to 8192 × 8192 pixels. By using artificial fractal images created by three different generator models as ground truth, we determined the scale ranges with minimum deviations between estimation and theory. All pyramidal methods (PM) resulted in reasonable D values for images of all generator models. Especially, for images with sizes ≥1024 ×1024 pixels, the PMs are superior to the investigated standard approaches in terms of accuracy and computation time. A measure for the possibility to differentiate images with different intrinsic D values did show not only that the PMs are well suited for all investigated image sizes, and preferable to standard methods especially for larger images, but also that results of standard D estimation techniques are strongly influenced by the image size. Fastest results were obtained with the PDM and PGM, followed by the PTPM. In terms of absolute D values best performing standard methods were magnitudes slower than the PMs. Concluding, the new PMs yield high quality results in short computation times and are therefore eligible methods for fast FA of high-resolution images.

  19. Hydrogen bonding to carbonyl oxygen of nitrogen-pyramidalized amide - detection of pyramidalization direction preference by vibrational circular dichroism spectroscopy.

    Science.gov (United States)

    Wang, Siyuan; Taniguchi, Tohru; Monde, Kenji; Kawahata, Masatoshi; Yamaguchi, Kentaro; Otani, Yuko; Ohwada, Tomohiko

    2016-03-01

    Nitrogen-pyramidalization of amide increases electron density on nitrogen and decreases that on carbonyl oxygen. We identified hydrogen-bonding to carbonyl of nitrogen-pyramidalized bicyclic β-proline derivatives by crystallography, and by NMR and vibrational circular dichroism (VCD) spectroscopy in solution. Such hydrogen-bonding can switch the preferred nitrogen-pyramidalization direction, as detected by VCD spectroscopy. PMID:26889607

  20. Pyramid Coarse Sun Sensing for NASA SSTI "Clark" Safe-Hold Mode

    OpenAIRE

    Benton, Jeff

    1996-01-01

    This paper describes an innovative approach to solving the Sun-pointing problem using a pyramid configuration of Coarse Sun Sensor (CSS) cells. In safe-hold mode, the Small Spacecraft Technology Initiative (SSTI) Clark spacecraft must keep its solar arrays towards the Sun using only CSS cells to sense the Sun. Unfortunately, Earth albedo degrades the accuracy of the Sun vector from these cells. Two CSS configurations are considered. A traditional configuration has cells mounted flat on each s...

  1. Acute Stress Facilitates Trace Eyeblink Conditioning in C57BL/6 Male Mice and Increases the Excitability of Their CA1 Pyramidal Neurons

    Science.gov (United States)

    Weiss, Craig; Sametsky, Evgeny; Sasse, Astrid; Spiess, Joachim; Disterhoft, John F.

    2005-01-01

    The effects of stress (restraint plus tail shock) on hippocampus-dependent trace eyeblink conditioning and hippocampal excitability were examined in C57BL/6 male mice. The results indicate that the stressor significantly increased the concentration of circulating corticosterone, the amount and rate of learning relative to nonstressed conditioned…

  2. How they (should have) built the pyramids

    CERN Document Server

    West, J; Waters, K

    2014-01-01

    A novel method is proposed for moving large, pyramid construction size, stone blocks. The method is inspired by a well known introductory physics homework problem, and is implemented by tying 12 identical rods of appropriately chosen radius to the faces of the block. The rods form the corners and new faces that transform the square prism into a dodecagon which can then be moved more easily by rolling than by dragging. Experimental results are presented and compared to independent work by another group which utilized wooden attachments providing a cylindrical shape. It is found that a small scale stone block converted to dodecagons can be moved across level open ground with a dynamic coefficient of friction of the order 0.2. For full scale pyramid blocks, the wooden rods would need to be posts of order 30 cm in diameter, similar in size to those used as masts on ships in the Nile.

  3. Approximate Particle Spectra in the Pyramid Scheme

    CERN Document Server

    Banks, Tom

    2012-01-01

    We construct a minimal model within the general class of Pyramid Schemes, which is consistent with both supersymmetry breaking and electroweak symmetry breaking. In order to do computations, we make unjustified approximations to the low energy K\\"ahler potential. The phenomenological viability of the resultant mass spectrum is then examined and compared with current collider limits. We show that, for certain regimes of parameters, the Pyramid Scheme can accommodate the current collider mass constraints on physics beyond the standard model with a tree-level light Higgs mass near 125 GeV. However, in this regime the model exhibits a little hierarchy problem, and one must permit fine-tunings that are generically 5%.

  4. An Analysis of Direct Hippocampal Cortical Field CA1 Axonal Projections to Diencephalon in the Rat

    OpenAIRE

    Cenquizca, Lee A.; Swanson, Larry W.

    2006-01-01

    The hippocampal formation is generally considered essential for processing episodic memory. However, the structural organization of hippocampal afferent and efferent axonal connections is still not completely understood, although such information is critical to support functional hypotheses. The full extent of axonal projections from field CA1 to the interbrain (diencephalon) is analyzed here with the Phaseolus vulgaris-leucoagglutinin (PHAL) method. The ventral pole of field CA1 establishes ...

  5. Entorhinal theta-frequency input to the dentate gyrus trisynaptically evokes hippocampal CA1 LTP

    OpenAIRE

    Jens Stepan; Matthias Eder

    2012-01-01

    There exists substantial evidence that some forms of explicit learning in mammals require long-term potentiation (LTP) at hippocampal CA3-CA1 synapses. While CA1 LTP has been well characterized at the monosynaptic level, it still remains unclear how the afferent systems to the hippocampus can initiate formation of this neuroplastic phenomenon. Using voltage-sensitive dye imaging in a mouse brain slice preparation, we show that evoked entorhinal cortical (EC) theta-frequency input to the denta...

  6. Entorhinal theta-frequency input to the dentate gyrus trisynaptically evokes hippocampal CA1 LTP

    OpenAIRE

    Stepan, Jens; Dine, Julien; Fenzl, Thomas; Polta, Stephanie A.; von Wolff, Gregor; Wotjak, Carsten T.; Eder, Matthias

    2012-01-01

    There exists substantial evidence that some forms of explicit learning in mammals require long-term potentiation (LTP) at hippocampal CA3-CA1 synapses. While CA1 LTP has been well characterized at the monosynaptic level, it still remains unclear how the afferent systems to the hippocampus can initiate formation of this neuroplastic phenomenon. Using voltage-sensitive dye imaging (VSDI) in a mouse brain slice preparation, we show that evoked entorhinal cortical (EC) theta-frequency input to th...

  7. The mode of synaptic activation of pyramidal neurons in the cat primary somatosensory cortex: an intracellular HRP study.

    Science.gov (United States)

    Yamamoto, T; Samejima, A; Oka, H

    1990-01-01

    A total of 141 pyramidal neurons in the cat primary somatosensory cortex (SI) were recorded intracellularly under Nembutal anesthesia (7 in layer II, 43 in layer III, 8 in layer IV, 58 in layer V and 25 in layer VI). Most neurons were identified by intracellular staining with HRP, though some layer V pyramidal neurons were identified only electrophysiologically with antidromic activation of medullary pyramid (PT) or pontine nuclear (PN) stimulation. Excitatory synaptic potentials (EPSPs) were analyzed with stimulation of the superficial radial nerve (SR), the ventral posterolateral nucleus (VPL) in the thalamus and the thalamic radiation (WM). The pyramidal neurons in layers III and IV received EPSPs at the shortest latency: 9.1 +/- 2.1 ms (Mean +/- S.D.) for SR and 1.6 +/- 0.7 ms for VPL stimulation. Layer II pyramidal neurons also responded at a short latency to VPL stimulation (1.7 +/- 0.5 ms), though their mean latencies for SR-induced EPSPs were relatively longer (10.6 +/- 1.9 ms). The mean latencies were much longer in layers V and VI pyramidal neurons (10.2 +/- 2.4 ms and 2.9 +/- 1.5 ms in layer V pyramidal neurons and 9.9 +/- 2.5 ms and 2.8 +/- 1.6 ms in layer VI pyramidal ones, respectively for SR and VPL stimulation). The comparison of the latencies between VPL and WM stimulation indicates that most layer III-IV pyramidal neurons and some pyramidal cells in layers II, V and VI received monosynaptic inputs from VPL. These findings are consistent with morphological data on the laminar distribution of thalamocortical fibers, i.e., thalamocortical fibers terminate mainly in the deeper part of layers III and IV with some collaterals in layers V, VI and II-I. The time-sequences of the latencies of VPL-EPSPs indicate that corticocortical and/or transcallosal neurons (pyramidal neurons in layers II and III) fire first and are followed by firing of the output neurons projecting to the subcortical structures (pyramidal neurons in layers V and VI). PMID:2358022

  8. Centre of pressure correlates with pyramid performance in acrobatic gymnastics.

    Science.gov (United States)

    Floría, Pablo; Gómez-Landero, Luis Arturo; Harrison, Andrew J

    2015-01-01

    Acrobatic gymnasts need excellent balance control to execute pyramids where one gymnast is supported by another. The objectives of this study were: (1) to describe balance performance by assessing the centre of pressure displacement in a group of acrobatic gymnasts executing pyramids; (2) to determine the relationship between the parameters describing the centre of pressure oscillations and pyramid score; and (3) to examine the role of each foot in providing a solid base of support to maintain the balance of the pyramid. Sixteen acrobatic gymnasts grouped in pairs performed a Half pyramid and a Straddle pyramid held for 7 s on two force platforms. Path length, variance, range trajectory, and surface area of the centre of pressure of each foot were examined to analyse the balance of the pyramid. The path length was correlated with the pyramid score (Straddle: p = 0.692 [large]; Half: p = 0.407 [moderate]). There were differences in the functions of each leg to maintain balance, with the non-preferred leg supporting a higher weight of the pyramid while the preferred leg performed control movements to maintain balance. The results suggested that quantitative analysis of balance can provide important information on pyramid performance. PMID:26715236

  9. Identification of cells in rat brain and peripheral tissues expressing mRNA for members of the nerve growth factor family.

    Science.gov (United States)

    Ernfors, P; Wetmore, C; Olson, L; Persson, H

    1990-10-01

    Cells expressing mRNA for hippocampus-derived neurotrophic factor (HDNF/NT-3) or brain-derived neurotrophic factor (BDNF) were identified by in situ hybridization. In the rat brain, HDNF mRNA was predominantly found in pyramidal neurons in CA1 and CA2 of the hippocampus. Lower levels of HDNF mRNA were found in granular neurons of the dentate gyrus and in neurons of the taenia tecta and induseum griseum. BDNF mRNA-expressing cells were more widely distributed in the rat brain, with high levels in neurons of CA2, CA3, and the hilar region of the dentate gyrus, in the external and internal pyramidal layers of the cerebral cortex, in the claustrum, and in one brainstem structure. Lower levels were seen in CA1 and in the granular layer of the hippocampus, in the taenia tecta, and in the mammillary complex. In peripheral tissues, HDNF mRNA was found in glomerular cells in the kidney, secretory cells in the male rat submandibular gland, and epithelial cells in secondary and tertiary follicles in the ovary. Cells expressing BDNF mRNA were found in the dorsal root ganglia, where neurons of various sizes were labeled. PMID:2206535

  10. Localization of peroxisome proliferator-activated receptor alpha (PPARα) and N-acyl phosphatidylethanolamine phospholipase D (NAPE-PLD) in cells expressing the Ca(2+)-binding proteins calbindin, calretinin, and parvalbumin in the adult rat hippocampus.

    Science.gov (United States)

    Rivera, Patricia; Arrabal, Sergio; Vargas, Antonio; Blanco, Eduardo; Serrano, Antonia; Pavón, Francisco J; Rodríguez de Fonseca, Fernando; Suárez, Juan

    2014-01-01

    The N-acylethanolamines (NAEs), oleoylethanolamide (OEA) and palmithylethanolamide (PEA) are known to be endogenous ligands of PPARα receptors, and their presence requires the activation of a specific phospholipase D (NAPE-PLD) associated with intracellular Ca(2+) fluxes. Thus, the identification of a specific population of NAPE-PLD/PPARα-containing neurons that express selective Ca(2+)-binding proteins (CaBPs) may provide a neuroanatomical basis to better understand the PPARα system in the brain. For this purpose, we used double-label immunofluorescence and confocal laser scanning microscopy for the characterization of the co-existence of NAPE-PLD/PPARα and the CaBPs calbindin D28k, calretinin and parvalbumin in the rat hippocampus. PPARα expression was specifically localized in the cell nucleus and, occasionally, in the cytoplasm of the principal cells (dentate granular and CA pyramidal cells) and some non-principal cells of the hippocampus. PPARα was expressed in the calbindin-containing cells of the granular cell layer of the dentate gyrus (DG) and the SP of CA1. These principal PPARα(+)/calbindin(+) cells were closely surrounded by NAPE-PLD(+) fiber varicosities. No pyramidal PPARα(+)/calbindin(+) cells were detected in CA3. Most cells containing parvalbumin expressed both NAPE-PLD and PPARα in the principal layers of the DG and CA1/3. A small number of cells containing PPARα and calretinin was found along the hippocampus. Scattered NAPE-PLD(+)/calretinin(+) cells were specifically detected in CA3. NAPE-PLD(+) puncta surrounded the calretinin(+) cells localized in the principal cells of the DG and CA1. The identification of the hippocampal subpopulations of NAPE-PLD/PPARα-containing neurons that express selective CaBPs should be considered when analyzing the role of NAEs/PPARα-signaling system in the regulation of hippocampal functions. PMID:24672435

  11. Localization of peroxisome proliferator-activated receptor alpha (PPARα and N-acyl phosphatidylethanolamine phospholipase D (NAPE-PLD in cells expressing the Ca2+-binding proteins calbindin, calretinin and parvalbumin in the adult rat hippocampus

    Directory of Open Access Journals (Sweden)

    Eduardo Blanco Calvo

    2014-03-01

    Full Text Available The N-acylethanolamines (NAEs oleoylethanolamide and palmithylethanolamide are known to be endogenous ligands of PPARα receptors, and their presence requires the activation of a specific phospholipase D (NAPE-PLD associated with intracellular Ca2+ fluxes. Thus, the identification of a specific population of NAPE-PLD/PPARα-containing neurons that express selective Ca2+-binding proteins (CaBPs may provide a neuroanatomical basis to better understand the PPARα system in the brain. For this purpose, we used double-label immunofluorescence and confocal laser scanning microscopy for the characterization of the co-existence of NAPE-PLD/PPARα and the CaBPs calbindin D28k, calretinin and parvalbumin in the rat hippocampus. PPARα expression was specifically localized in the cell nucleus and, occasionally, in the cytoplasm of the principal cells (dentate granular and CA pyramidal cells and some non-principal cells of the hippocampus. PPARα was expressed in the calbindin-containing cells of the granular cell layer of the dentate gyrus (DG and the SP of CA1. These principal PPARα+/calbindin+ cells were closely surrounded by NAPE-PLD+ fiber varicosities. No pyramidal PPARα+/calbindin+ cells were detected in CA3. Most cells containing parvalbumin expressed both NAPE-PLD and PPARα in the principal layers of the DG and CA1/3. A small number of cells containing PPARα and calretinin was found along the hippocampus. Scattered NAPE-PLD+/calretinin+ cells were specifically detected in CA3. NAPE-PLD+ puncta surrounded the calretinin+ cells localized in the principal cells of the DG and CA1. The identification of the hippocampal subpopulations of NAPE-PLD/PPARα-containing neurons that express selective CaBPs should be considered when analyzing the role of NAEs/PPARα-signaling system in the regulation of hippocampal functions.

  12. Ethanol enhances neurosteroidogenesis in hippocampal pyramidal neurons by paradoxical NMDA receptor activation.

    Science.gov (United States)

    Tokuda, Kazuhiro; Izumi, Yukitoshi; Zorumski, Charles F

    2011-07-01

    Using an antibody against 5α-reduced neurosteroids, predominantly allopregnanolone, we found that immunostaining in the CA1 region of rat hippocampal slices was confined to pyramidal neurons. This neurosteroid staining was increased following 15 min administration of 60 mm but not 20 mm ethanol, and the enhancement was blocked by finasteride and dutasteride, selective inhibitors of 5α-reductase, a key enzyme required for allopregnanolone synthesis. Consistent with a prior report indicating that N-methyl-D-aspartate (NMDA) receptor (NMDAR) activation can promote steroid production, we observed that D-2-amino-5-phosphonovalerate (APV), a competitive NMDAR antagonist, blocked the effects of 60 mm ethanol on staining. We previously reported that 60 mm ethanol inhibits the induction of long-term potentiation (LTP), a cellular model for memory formation, in the CA1 region. In the present study, LTP inhibition by 60 mm ethanol was also overcome by both the 5α-reductase inhibitors and by APV. Furthermore, the effects of ethanol on neurosteroid production and LTP were mimicked by a low concentration of NMDA (1 μm), and the ability of NMDA to inhibit LTP and to enhance neurosteroid staining was reversed by finasteride and dutasteride, as well as by APV. These results indicate that ethanol paradoxically enhances GABAergic neurosteroid production by activation of unblocked NMDARs and that acute LTP inhibition by ethanol represents a form of NMDAR-mediated metaplasticity. PMID:21734282

  13. Design and fabrication of a pyramid wavefront sensor

    Science.gov (United States)

    Wang, Aina; Yao, Jun; Cai, Dongmei; Ren, Hao

    2010-07-01

    A new pyramid wavefront sensor (PWFS), which utilizes a reflective pyramid mirror instead of a refractive pyramid prism at the focus of a telescope, is presented. As a key optical component in this PWFS, the pyramid mirror requires accurate microfabrication for excellent quality of the tip, the turned edges, and the surfaces. The moving mask lithography process is proposed for its economic, simple, and precise control to make the cross-sectional shape of the structure. The completed pyramid mirror has a square base of 1-mm length and four side facets inclined to the base at 3.7 deg. The sizes of the pyramid tip and turned edges are both about 6 μm, which show excellent aspects of sharpening-tip and knife-edges. The root mean square of four facets is approximately 70 nm, and the maximum profile deviation is 0.2 μm.

  14. Right-hemispheric Dominance Of Dentate Granule Cell Activity After Spatial Exploration In Split-brain Mice But Not In Acallosal Mutant Mice

    OpenAIRE

    Hassan Ahmed; RYOSUKE KAWAKAMI; Fukazawa, Yugo; Ryuichi Shigemoto

    2013-01-01

    In the last decade, left/right brain asymmetry studies have been focused on the molecular level of the hippocampus. First, left/right asymmetry has been reported in GluN2B-NMDA subunit distribution and synaptic plasticity in hippocampal pyramidal cell synapses depending on the side of input (Kawakami et al, 2003). Furthermore, Shinohara et al (2008) found that GluA1-AMPA receptor subunit density, PSD size and spine head volume are larger in CA1 radiatum synapses contacting with presynaptic fi...

  15. Facial action detection using block-based pyramid appearance descriptors

    OpenAIRE

    Jiang, Bihan; Valstar, Michel F.; Pantic, Maja

    2012-01-01

    Facial expression is one of the most important non-verbal behavioural cues in social signals. Constructing an effective face representation from images is an essential step for successful facial behaviour analysis. Most existing face descriptors operate on the same scale, and do not leverage coarse v.s. fine methods such as image pyramids. In this work, we propose the sparse appearance descriptors Block-based Pyramid Local Binary Pattern (B-PLBP) and Block-based Pyramid Local Phase Quantisati...

  16. General Mechanisms for Inverted Biomass Pyramids in Ecosystems

    OpenAIRE

    Wang, Hao; Morrison, Wendy; Singh, Abhinav; Weiss, Howard

    2008-01-01

    Although the existence of robust inverted biomass pyramids seem paradoxical, they have been observed in planktonic communities, and more recently, in pristine coral reefs. Understanding the underlying mechanisms which produce inverted biomass pyramids provides new ecological insights, and for coral reefs, may help mitigate or restore damaged reefs. We present three classes of predator-prey models which elucidate mechanisms that generate robust inverted biomass pyramids. The first class of mod...

  17. Comparison of Morphological Pyramids for Multiresolution MIP Volume Rendering

    OpenAIRE

    Roerdink, Jos B. T. M.

    2002-01-01

    We recently proposed a multiresolution representation for maximum intensity projection (MIP) volume rendering based on morphological adjunction pyramids which allow progressive refinement and have the property of perfect reconstruction. In this algorithm the pyramidal analysis and synthesis operators are composed of morphological erosion and dilation, combined with dyadic downsampling for analysis and dyadic upsampling for synthesis. Here we introduce an alternative pyramid scheme in which a ...

  18. A top-down construction scheme for irregular pyramids

    OpenAIRE

    Goffe, Romain; Brun, Luc; Damiand, Guillaume

    2009-01-01

    Hierarchical data structures such as irregular pyramids are used by many applications related to image processing and segmentation. The construction scheme of such pyramids is bottom-up. Such a scheme forbids the definition of a level according to more global information defined at upper levels in the hierarchy. Moreover, the base of the pyramid has to encode any single pixel of the initial image in order to allow the definition of regions of any shape at higher levels. This last constraint r...

  19. Incidence of a pyramidal lobe on thyroid scans

    International Nuclear Information System (INIS)

    Gamma camera pertechnetate and radioiodine thyroid scans were reviewed to determine the incidence of recognition of a pyramidal lobe. Ten to 17% of normals and of patients with various thyroid disease states had a pyramidal lobe on their scans. However, in patients with diffuse toxic goiter, 43% had a pyramidal lobe on the thyroid images. There appears to be a correlation between elevated thyroid function studies (likely in thyroid mass) and the incidence of a pyramidal lobe on thyroid scans in diffuse toxic goiter

  20. Base-of-the-pyramid global strategy

    Directory of Open Access Journals (Sweden)

    Boşcor, D.

    2010-12-01

    Full Text Available Global strategies for MNCs should focus on customers in emerging and developing markets instead of customers in developed economies. The “base-of-the-pyramid segment” comprises 4 billion people in the world. In order to be successful, companies will be required to form unconventional partnerships- with entities ranging from local governments to non-profit organizations - to gain the community’s trust and understand the environmental, infrastructure and political issues that may affect business. Being able to provide affordable, high-quality products and services in this market segment often means new approaches to marketing- new packaging and pricing structures, and using unfamiliar distribution structures.

  1. Cosmological SUSY Breaking and the Pyramid Schemes

    CERN Document Server

    Banks, T

    2014-01-01

    I review the ideas of holographic space-time (HST), Cosmological SUSY breaking (CSB), and the Pyramid Schemes, which are the only known models of Tera-scale physics consistent with CSB, current particle data, and gauge coupling unification. There is considerable uncertainty in the estimate of the masses of supersymmetric partners of the standard model particles, but the model predicts that the gluino is probably out of reach of the LHC, squarks may be in reach, and the NLSP is a right handed slepton, which should be discovered soon.

  2. Dirac Gluinos in the Pyramid Scheme

    CERN Document Server

    Banks, T

    2013-01-01

    I point out several terms in the low energy effective Lagrangian of the Pyramid Scheme, which were missed in a previous analysis of the phenomenological consequences of the model. They lead to a Dirac contribution to the gluino mass, much larger than the one loop Majorana mass. The gluino can thus be much heavier than in previous estimates, without introducing corresponding large loop corrections to squark masses. As pointed out by a number of authors, this ameliorates the tension between the predictions of the model, and LHC data. I also point out that the model has corrections to the Higgs potential, both at the tree and loop levels, which may ameliorate fine tuning.

  3. Thermoelectric properties of Zintl compound Ca1-xNaxMg2Bi1.98

    Science.gov (United States)

    Shuai, Jing; Kim, Hee Seok; Liu, Zihang; He, Ran; Sui, Jiehe; Ren, Zhifeng

    2016-05-01

    Motivated by good thermoelectric performance of Bi-based Zintl compounds Ca1-xYbxMg2Biy, we further studied the thermoelectric properties of Zintl compound CaMg2Bi1.98 by doping Na into Ca as Ca1-xNaxMg2Bi1.98 via mechanical alloying and hot pressing. We found that the electrical conductivity, Seebeck coefficient, power factor, and carrier concentration can be effectively adjusted by tuning the Na concentration. Transport measurement and calculations revealed that an optimal doping of 0.5 at. % Na achieved better average ZT and efficiency. The enhancement in thermoelectric performance is attributed to the increased carrier concentration and power factor. The low cost and nontoxicity of Ca1-xNaxMg2Bi1.98 makes it a potentially promising thermoelectric material for power generation in the mid-temperature range.

  4. Novel chemically stable Ba3Ca1.18Nb1.82-xYxO9- proton conductor: improved proton conductivity through tailored cation ordering

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Siwei [University of South Carolina, Columbia; Chen, Yan [ORNL; Fang, Shumin [University of South Carolina, Columbia; Zhang, Lingling [University of South Carolina, Columbia; Tang, Ming [Los Alamos National Laboratory (LANL); An, Ke [ORNL; Brinkman, Dr. Kyle S. [Savannah River National Laboratory (SRNL), Aiken, S.C.; Chen, Fanglin [University of South Carolina, Columbia

    2014-01-01

    Simple perovskite-structured proton conductors encounter significant challenges to simultaneously achieving excellent chemical stability and proton conductivity that are desirable for many important applications in energy conversion and storage. This work demonstrates that Y-doped complex-perovskite-structured Ba3Ca1.18Nb1.82 xYxO9 materials possess both improved proton conductivity and exceptional chemical stability. Neutron powder diffraction refinement revealed a Fm3 m perovskite-structure and increased oxygen vacancy concentration due to the Y doping. High-resolution TEM analysis confirmed the perturbation of the B site cation ordering in the structure for the Ba3Ca1.18Nb1.82 xYxO9 materials. Such combined effects led to improved proton conductivity with a value of 5.3 10 3 S cm 1 at 600 C for Ba3Ca1.18Nb1.52Y0.3O9 (BCNY0.3), a value 2.4 times higher compared with that of the undoped Ba3Ca1.18Nb1.82O9 . The Ba3Ca1.18Nb1.82 xYxO9 materials showed remarkable chemical stability toward water and demonstrated no observable reactions to CO2 exposure. Ionic transport number studies showed that BCNY0.3 had predominantly proton conduction below 600 C. Solid oxide fuel cells using BCNY0.3 as an electrolyte demonstrated cell power output of 103 mW cm 2 at 750 C. These results suggest that a doping strategy that tailors the cation ordering in complex perovskites provides a new direction in the search for novel proton conducting ceramics.

  5. (Zn, Ca) Solid-Solution Behavior and Its Effect on Luminescence Properties in Ca1- xZnx TiO3: 0.002Pr3+ Phosphors

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Nominal composition of Ca1 - xZnxTiO3: 0. 002Pr3 + ( x = 0. 000 ~ 0. 200) phosphors were prepared by conventional solid reaction route. XRD and PL measurements were used to investigate the solid-solution structure and luminescence properties of Zn-doped Ca1- xZnxTiO3:0. 002Pr3 + phosphors. The effect of solid-solution structure formed by substitution between Ca2 + and Zn2 + ions on the luminescent properties was analyzed. The results reveal that, with the increase of Zn substitution content below 0.010, lattice parameters and the intensity of excitation peak at both 260 and 330 nm as well as the corresponding 610 nm emission intensity are monotonously decreased quickly in a similar tendency. Also, the evolution of luminescence intensity and crystal cell parameters against Zn doping concentration are in good agreement.Above results are closely related with the structure change within Ca1- xZnxTiO3:0. 002Pr3 + solid-solution phase formed by the Zn ions substitution for the Ca sites. Present study reveals that the solid-solution structure formed by substitution between Ca2 + and Zn2 + ions has significant effect on the luminescence properties of single phase Ca1- xZnxTiO3:0.002Pr3 +phosphors.

  6. Conserved size and periodicity of pyramidal patches in layer 2 of medial/caudal entorhinal cortex.

    Science.gov (United States)

    Naumann, Robert K; Ray, Saikat; Prokop, Stefan; Las, Liora; Heppner, Frank L; Brecht, Michael

    2016-03-01

    To understand the structural basis of grid cell activity, we compare medial entorhinal cortex architecture in layer 2 across five mammalian species (Etruscan shrews, mice, rats, Egyptian fruit bats, and humans), bridging ∼100 million years of evolutionary diversity. Principal neurons in layer 2 are divided into two distinct cell types, pyramidal and stellate, based on morphology, immunoreactivity, and functional properties. We confirm the existence of patches of calbindin-positive pyramidal cells across these species, arranged periodically according to analyses techniques like spatial autocorrelation, grid scores, and modifiable areal unit analysis. In rodents, which show sustained theta oscillations in entorhinal cortex, cholinergic innervation targeted calbindin patches. In bats and humans, which only show intermittent entorhinal theta activity, cholinergic innervation avoided calbindin patches. The organization of calbindin-negative and calbindin-positive cells showed marked differences in entorhinal subregions of the human brain. Layer 2 of the rodent medial and the human caudal entorhinal cortex were structurally similar in that in both species patches of calbindin-positive pyramidal cells were superimposed on scattered stellate cells. The number of calbindin-positive neurons in a patch increased from ∼80 in Etruscan shrews to ∼800 in humans, only an ∼10-fold over a 20,000-fold difference in brain size. The relatively constant size of calbindin patches differs from cortical modules such as barrels, which scale with brain size. Thus, selective pressure appears to conserve the distribution of stellate and pyramidal cells, periodic arrangement of calbindin patches, and relatively constant neuron number in calbindin patches in medial/caudal entorhinal cortex. PMID:26223342

  7. A Pyramid Scheme for Particle Physics

    CERN Document Server

    Banks, Tom

    2009-01-01

    We introduce a new model, the Pyramid Scheme, of direct mediation of SUSY breaking, which is compatible with the idea of Cosmological SUSY Breaking (CSB). It uses the trinification scheme of grand unification and avoids problems with Landau poles in standard model gauge couplings. It also avoids problems, which have recently come to light, associated with rapid stellar cooling due to emission of the pseudo Nambu-Goldstone Boson (PNGB) of spontaneously broken hidden sector baryon number. With a certain pattern of R-symmetry breaking masses, a pattern more or less required by CSB, the Pyramid Scheme leads to a dark matter candidate that decays predominantly into leptons, with cross sections compatible with a variety of recent observations. The dark matter particle is not a thermal WIMP but a particle with new strong interactions, produced in the late decay of some other scalar, perhaps the superpartner of the QCD axion, with a reheat temperature in the TeV range. This is compatible with a variety of scenarios f...

  8. The Alphabet Pyramid of Team Development and Situation Leadership.

    Science.gov (United States)

    Jarvis, Roy

    2001-01-01

    This pyramid model of team development has four sides--awareness, behavior, communication, and direction--on a foundation of evaluation. The four equal sides of a pyramid represent the equal importance of the different roles, including leader, within a team. All team members are involved in evaluation and deciding what is important, which empowers…

  9. Building Influenza Surveillance Pyramids in Near Real Time, Australia

    OpenAIRE

    Dalton, Craig B; Carlson, Sandra J.; Butler, Michelle T; Elvidge, Elissa; Durrheim, David N

    2013-01-01

    A timely measure of circulating influenza virus severity has been elusive. Flutracking, the Australian online influenza-like illness surveillance system, was used to construct a surveillance pyramid in near real time for 2011/2012 participants and demonstrated a striking difference between years. Such pyramids will facilitate rapid estimation of attack rates and disease severity.

  10. nD generalized map pyramids: definition, representations and basic operations

    OpenAIRE

    Grasset-Simon, Carine; Damiand, Guillaume; Lienhardt, Pascal

    2006-01-01

    Graph pyramids are often used for representing irregular image pyramids. For the 2D case, combinatorial pyramids have been recently defined in order to explicitly represent more topological information than graph pyramids. The main contribution of this work is the definition of pyramids of $n$-dimensional generalized maps. This extends the previous works to any dimension, and generalizes them in order to represent any type of pyramid built by using any removal and/or contraction operations. W...

  11. Neuronal glutamate transporters regulate synaptic transmission in single synapses on CA1 hippocampal neurons.

    Science.gov (United States)

    Kondratskaya, Elena; Shin, Min-Chul; Akaike, Norio

    2010-01-15

    Glutamate is the major excitatory transmitter in CNS although it causes severe brain damage by pathologic excitotoxicity. Efficient neurotransmission is controlled by powerful protection and support afforded by specific high-affinity glutamate transporters in neurons and glia, clearing synaptic glutamate. While the role of glial cells in glutamate uptake is well defined, the role of neuronal transporters remains poorly understood. The evaluation of impact of neuronal transporters on spontaneous and evoked EPSC in hippocampal CA1 neurons within a model 'single bouton preparation' by pre- and postsynaptic uptake was addressed. In whole-cell patch clamp experiments the influence of blocking, pre- or both pre- and postsynaptic glutamate transporters (GluT) on spontaneous and evoked postsynaptic currents (sEPSC and eEPSC), was examined by manipulating the content of intracellular solution. Suppressing GluT by non-transportable inhibitor TBOA (10 microM) led to remarkable alteration of glutamate uptake process and was reflected in measurable changes of general properties of synaptic currents. Elimination of intracellular K(+) concentration required for glutamate transporter operation by using Cs(+)-based internal solution (postsynaptic GluTs are non-functional apriori), causes the deficient of presynaptic glutamate transporters. Applied in such conditions glutamate transporter inhibitor TBOA (10 microM) affected the occurrence of synaptic event and thus unregulated the transmitter release. eEPSCs were generally suppressed both in amplitude (to 48.73+/-7.03% vs. control) and in success rate (R(suc)) by TBOA (from 91.1+/-7.5% in control to 79.57+/-13.2%). In contrast, with K(+)-based solution in patch pipette (pre- and postsynaptic GluT are intact), amplitude of eEPSC was substantially potentiated by pre-treatment with TBOA (152.1+/-11%), whereas (R(suc)) was reduced to 79.8+/-8.3% in average. The identical reduction of event success rate as well as increased pair

  12. The NGS Pyramid wavefront sensor for ERIS

    Science.gov (United States)

    Riccardi, A.; Antichi, J.; Quirós-Pacheco, F.; Esposito, S.; Carbonaro, L.; Agapito, G.; Biliotti, V.; Briguglio, R.; Di Rico, G.; Dolci, M.; Ferruzzi, D.; Pinna, E.; Puglisi, A.; Xompero, M.; Marchetti, E.; Fedrigo, E.; Le Louarn, M.; Conzelmann, R.; Delabre, B.; Amico, P.; Hubin, N.

    2014-07-01

    ERIS is the new Single Conjugate Adaptive Optics (AO) instrument for VLT in construction at ESO with the collaboration of Max-Planck Institut fuer Extraterrestrische Physik, ETH-Institute for Astronomy and INAF - Osservatorio Astrofisico di Arcetri. The ERIS AO system relies on a 40×40 sub-aperture Pyramid Wavefront Sensor (PWFS) for two operating modes: a pure Natural Guide Star high-order sensing for high Strehl and contrast correction and a low-order visible sensing in support of the Laser Guide Star AO mode. In this paper we present in detail the preliminary design of the ERIS PWFS that is developed under the responsibility of INAF-Osservatorio Astrofisico di Arcetri in collaboration with ESO.

  13. Comparison between basal and apical dendritic spines in estrogen-induced rapid spinogenesis of CA1 principal neurons in the adult hippocampus

    International Nuclear Information System (INIS)

    Modulation of hippocampal synaptic plasticity by estrogen has been attracting much attention. Here, we demonstrated the rapid effect of 17β-estradiol on the density and morphology of spines in the stratum oriens (s.o., basal side) and in the stratum lacunosum-moleculare (s.l.m., apical side) by imaging Lucifer Yellow-injected CA1 neurons in adult male rat hippocampal slices, because spines in s.o. and s.l.m. have been poorly understood as compared with spines in the stratum radiatum. The application of 1 nM estradiol-induced a rapid increase in the density of spines of pyramidal neurons within 2 h. This increase by estradiol was blocked by Erk MAP kinase inhibitor and estrogen receptor inhibitor in both regions. Effect of blockade by agonists of AMPA receptors and NMDA receptors was different between s.o. and s.l.m. In both regions, ERα agonist PPT induced the same enhancing effect of spinogenesis as that induced by estradiol

  14. Synaptically evoked dendritic action potentials in rat neocortical pyramidal neurons.

    Science.gov (United States)

    Schwindt, P C; Crill, W E

    1998-05-01

    In a previous study iontophoresis of glutamate on the apical dendrite of layer 5 pyramidal neurons from rat neocortex was used to identify sites at which dendritic depolarization evoked small, prolonged Ca2+ spikes and/or low-threshold Na+ spikes recorded by an intracellular microelectrode in the soma. These spikes were identified as originating in the dendrite. Here we evoke similar dendritic responses by electrical stimulation of presynaptic elements near the tip of the iontophoretic electrode with the use of a second extracellular electrode. In 9 of 12 recorded cells, electrically evoked excitatory postsynaptic potentials (EPSPs) above a minimum size triggered all-or-none postsynaptic responses similar to those evoked by dendritic glutamate iontophoresis at the same site. Both the synaptically evoked and the iontophoretically evoked depolarizations were abolished reversibly by blockade of glutamate receptors. In all recorded cells, the combination of iontophoresis and an EPSP, each of which was subthreshold for the dendritic spike when given alone, evoked a dendritic spike similar to that evoked by a sufficiently large iontophoresis. In one cell tested, dendritic spikes could be evoked by the summation of two independent subthreshold EPSPs evoked by stimulation at two different locations. We conclude that the dendritic spikes are not unique to the use of glutamate iontophoresis because similar spikes can be evoked by EPSPs. We discuss the implications of these results for synaptic integration and for the interpretation of recorded synaptic potentials. PMID:9582218

  15. Synaptic remodeling in the dentate gyrus, CA3, CA1, subiculum, and entorhinal cortex of mice: effects of deprived rearing and voluntary running.

    Science.gov (United States)

    Schaefers, Andrea T U; Grafen, Keren; Teuchert-Noodt, Gertraud; Winter, York

    2010-01-01

    Hippocampal cell proliferation is strongly increased and synaptic turnover decreased after rearing under social and physical deprivation in gerbils (Meriones unguiculatus). We examined if a similar epigenetic effect of rearing environment on adult neuroplastic responses can be found in mice (Mus musculus). We examined synaptic turnover rates in the dentate gyrus, CA3, CA1, subiculum, and entorhinal cortex. No direct effects of deprived rearing on rates of synaptic turnover were found in any of the studied regions. However, adult wheel running had the effect of leveling layer-specific differences in synaptic remodeling in the dentate gyrus, CA3, and CA1, but not in the entorhinal cortex and subiculum of animals of both rearing treatments. Epigenetic effects during juvenile development affected adult neural plasticity in mice, but seemed to be less pronounced than in gerbils. PMID:20508828

  16. Synaptic Remodeling in the Dentate Gyrus, CA3, CA1, Subiculum, and Entorhinal Cortex of Mice: Effects of Deprived Rearing and Voluntary Running

    Directory of Open Access Journals (Sweden)

    Andrea T. U. Schaefers

    2010-01-01

    Full Text Available Hippocampal cell proliferation is strongly increased and synaptic turnover decreased after rearing under social and physical deprivation in gerbils (Meriones unguiculatus. We examined if a similar epigenetic effect of rearing environment on adult neuroplastic responses can be found in mice (Mus musculus. We examined synaptic turnover rates in the dentate gyrus, CA3, CA1, subiculum, and entorhinal cortex. No direct effects of deprived rearing on rates of synaptic turnover were found in any of the studied regions. However, adult wheel running had the effect of leveling layer-specific differences in synaptic remodeling in the dentate gyrus, CA3, and CA1, but not in the entorhinal cortex and subiculum of animals of both rearing treatments. Epigenetic effects during juvenile development affected adult neural plasticity in mice, but seemed to be less pronounced than in gerbils.

  17. Fabrication and measurement of a flexoelectric micro-pyramid composite

    Science.gov (United States)

    Huang, Wenbin; Shu, Longlong; Ryung Kwon, Seol; Zhang, Shujun; Yuan, Fuh-Gwo; Jiang, Xiaoning

    2014-12-01

    A fabrication method by combining precision mechanical dicing and wet etching was developed to prepare micro-pyramid structures based on (Ba0.67Sr0.33)TiO3 ceramics. The effective piezoelectric properties of flexoelectric pyramid structures in ten micrometers scale were investigated and measured through converse flexoelectric effect. The scaling effect of the flexoelectric response was demonstrated as the structure size shrinks down. The results do suggest the great potential of flexoelectric micro pyramids as an alternative to lead-free piezoelectric material.

  18. NONLINEAR BENDING THEORY OF DIAGONAL SQUARE PYRAMID RETICULATED SHALLOW SHELLS

    Institute of Scientific and Technical Information of China (English)

    肖潭; 刘人怀

    2001-01-01

    Double-deck reticulated shells are a main form of large space structures. One of the shells is the diagonal square pyramid reticulated shallow shell, whose its upper and lower faces bear most of the load but its core is comparatively flexible. According to its geometrical and mechanical characteristics, the diagonal square pyramid reticulated shallow shell is treated as a shallow sandwich shell on the basis of three basic assumptions. Its constitutive relations are analyzed from the point of view of energy and internal force equivalence. Basic equations of the geometrically nonlinear bending theory of the diagonal square pyramid reticulated shallow shell are established by means of the virtual work principle .

  19. Papillary Carcinoma Arising from the Pyramidal Lobe of the Thyroid

    International Nuclear Information System (INIS)

    The authors present a rare case of papillary carcinoma arising from the pyramidal lobe of the thyroid in a 54-year-old woman, who presented with a right submental palpable mass. An ultrasound evaluation depicted a 3 cm mixed echoic mass from the thyroid cartilage level without a focal lesion in the thyroid gland. Surgical specimens obtained during bilateral thyroidectomy confirmed papillary carcinoma of the pyramidal lobe. To the authors' knowledge, this is the first case report to describe papillary carcinoma arising from the pyramidal lobe of the thyroid gland

  20. MAPK SIGNALING IS CRITICAL TO ESTRADIOL PROTECTION OF CA1 NEURONS IN GLOBAL ISCHEMIA

    OpenAIRE

    Jover-Mengual, Teresa; Zukin, R. Suzanne; Etgen, Anne M.

    2006-01-01

    The importance of hormone therapy in affording protection against the sequelae of global ischemia in postmenopausal women remains controversial. Global ischemia arising during cardiac arrest or cardiac surgery causes highly selective, delayed death of hippocampal CA1 neurons. Exogenous estradiol ameliorates global ischemia-induced neuronal death and cognitive impairment in male and female rodents. However, the molecular mechanisms by which estrogens intervene in global ischemia-induced apopto...

  1. Effects of carnosine on the evoked potentials in hippocampal CA1 region*

    OpenAIRE

    Feng, Zhou-yan; Zheng, Xiao-jing; Wang, Jing

    2009-01-01

    Objective: To directly examine the effects of carnosine on neuronal excitation and inhibition in rat hippocampus in vivo. Methods: Artificial cerebrospinal fluid with carnosine was directly administrated over the exposed rat hippocampus. The changes of neuron activity in the CA1 region of hippocampus were evaluated by orthodromically- and antidromically-evoked potentials, as well as paired-pulse stimulation paradigm. Results: In both orthodromic and antidromic response potentials, carnosine t...

  2. Regulation of Astroglia on Synaptic Plasticity in the CA1 Region of Rat Hippocampus

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The regulation of astroglia on synaptic plasticity in the CA1 region of rat hippocampus was examined. Rats were divided into three groups: the newly born (<24 h), the juvenile (28-30days) and the adult groups (90-100 days), with each group having 20 animals. The CA1 region of rat hippocampus was immunohistochemically and electron-microscopically examined, respectively,for the growth of astroglia and the ultrastructure of synapses. The high performance liquid chromatography was employed to determine the cholesterol content of rat hippocampus. In the newly-born rats, a large number of neurons were noted in the hippocampal CA1 region of the newly-born rats,and few astroglia and no synaptic structure were observed. In the juvenile group, a few astroglias and some immature synapses were found, which were less than those in adult rats (P<0.01). The cholesterol content was 2.92±0.03 mg/g, 11.20± 3.41 mg/g and 12.91 ± 1.25 mg/g for newly born, the juvenile and the adult groups, respectively, with the differences among them being statistically significant (P<0.01). Our study suggests that the astrocytes may play an important role in the synaptic formation and functional maturity of hippocampal neurons, which may be related to the secretion of cholesterol from astrocytes.

  3. Diffusion-weighted imaging in transient global amnesia exposes the CA1 region of the hippocampus

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ho Yun; Kim, Jae Hyoung; Weon, Young-Cheol; Youn, Sung Won; Kim, Sung Hyun [Seoul National University Bundang Hospital, Department of Radiology, Seoul National University College of Medicine, Seongnam-si (Korea); Lee, Jung Seok; Kim, Sang Yun [Seoul National University Bundang Hospital, Department of Neurology, Seoul National University College of Medicine, Seongnam-si (Korea)

    2007-06-15

    Transient global amnesia (TGA) is characterized by a sudden onset of anterograde amnesia without alteration of consciousness or personal identity. Interestingly, recent studies have reported a high frequency of small high-signal abnormalities in the hippocampus with diffusion-weighted (DW) imaging, and ischemia has been proposed as an etiology of TGA. We hypothesized that TGA lesions occur preferentially in the CA1 region of the hippocampus, known to be susceptible to ischemia. Over a 30-month period 34 patients with TGA underwent MRI including DW imaging within 4 days of symptom onset. Patients with high-signal abnormalities in the hippocampus on the initial DW images underwent subsequent DW and T2-weighted imaging in the coronal plane to identify the precise lesion locations. Fourteen patients had small (1-3 mm) high-signal abnormalities in the hippocampus unilaterally on DW images. One of these patients had two lesions in one hippocampus and therefore in total 15 lesions were identified: four in the hippocampal head, and 11 in the body. Eleven lesions in ten patients with available coronal images were clearly demonstrated on both coronal DW and T2-weighted images and were localized to the lateral portion of the hippocampus, corresponding to the CA1 region. Lesions associated with TGA were localized exclusively to the lateral portion of the hippocampus corresponding to the CA1 region. This finding supports the ischemic etiology of TGA; however, the pathophysiological mechanism involved requires further study. (orig.)

  4. Evidence of two superconducting phases in Ca1−xLaxFe2As2

    Directory of Open Access Journals (Sweden)

    Y. Sun

    2013-10-01

    Full Text Available Single crystals of Ca1−xLaxFe2As2 with x ranging from 0 to 0.25, have been grown and characterized by structural, transport, and magnetic measurements. Coexistence of two superconducting phases is observed, in which the phase with the lower superconducting transition temperature (Tc has Tc ∼ 20 K and the higher Tc phase has Tc higher than 40 K. These data also delineate an x-T phase diagram in which the single magnetic/structural phase transition in undoped CaFe2As2 appears to split into two distinct phase transitions, both of which are suppressed with increasing La substitution. Superconductivity emerges when x is about 0.06 and coexists with the structural/magnetic transition until x is ∼ 0.13. With increasing concentration of La, the structural/magnetic transition is totally suppressed, and Tc reaches its maximum value of about 45 K for 0.15 ⩽ x ⩽ 0.19. A domelike superconducting region is not observed in the phase diagram, however, because no obvious over-doping region can be found. Two superconducting phases coexist in the x-T phase diagram of Ca1−xLaxFe2As2. The formation of the two separate phases and the origin of the high Tc in Ca1−xLaxFe2As2 have been studied and discussed in detail.

  5. Diffusion-weighted imaging in transient global amnesia exposes the CA1 region of the hippocampus

    International Nuclear Information System (INIS)

    Transient global amnesia (TGA) is characterized by a sudden onset of anterograde amnesia without alteration of consciousness or personal identity. Interestingly, recent studies have reported a high frequency of small high-signal abnormalities in the hippocampus with diffusion-weighted (DW) imaging, and ischemia has been proposed as an etiology of TGA. We hypothesized that TGA lesions occur preferentially in the CA1 region of the hippocampus, known to be susceptible to ischemia. Over a 30-month period 34 patients with TGA underwent MRI including DW imaging within 4 days of symptom onset. Patients with high-signal abnormalities in the hippocampus on the initial DW images underwent subsequent DW and T2-weighted imaging in the coronal plane to identify the precise lesion locations. Fourteen patients had small (1-3 mm) high-signal abnormalities in the hippocampus unilaterally on DW images. One of these patients had two lesions in one hippocampus and therefore in total 15 lesions were identified: four in the hippocampal head, and 11 in the body. Eleven lesions in ten patients with available coronal images were clearly demonstrated on both coronal DW and T2-weighted images and were localized to the lateral portion of the hippocampus, corresponding to the CA1 region. Lesions associated with TGA were localized exclusively to the lateral portion of the hippocampus corresponding to the CA1 region. This finding supports the ischemic etiology of TGA; however, the pathophysiological mechanism involved requires further study. (orig.)

  6. Vector Symbolic Spiking Neural Network Model of Hippocampal Subarea CA1 Novelty Detection Functionality.

    Science.gov (United States)

    Agerskov, Claus

    2016-04-01

    A neural network model is presented of novelty detection in the CA1 subdomain of the hippocampal formation from the perspective of information flow. This computational model is restricted on several levels by both anatomical information about hippocampal circuitry and behavioral data from studies done in rats. Several studies report that the CA1 area broadcasts a generalized novelty signal in response to changes in the environment. Using the neural engineering framework developed by Eliasmith et al., a spiking neural network architecture is created that is able to compare high-dimensional vectors, symbolizing semantic information, according to the semantic pointer hypothesis. This model then computes the similarity between the vectors, as both direct inputs and a recalled memory from a long-term memory network by performing the dot-product operation in a novelty neural network architecture. The developed CA1 model agrees with available neuroanatomical data, as well as the presented behavioral data, and so it is a biologically realistic model of novelty detection in the hippocampus, which can provide a feasible explanation for experimentally observed dynamics. PMID:26890351

  7. Lax Ca1-xMnO5/Si异质结的光伏特性%Photovoltaic Properties of LaxCa1-xMnO3/Si Heterojunctions

    Institute of Scientific and Technical Information of China (English)

    吕志清; 冯鑫; 尼浩; 赵昆; Wong Hong-Kuen; Kong Yu-Chau

    2013-01-01

    Doped manganite was a kind of important function materials, which recently drew many attentions for its photoelectric properties. Manganite oxide heterojunctions of LaxCa1-xMnO3 (x =0. 4 and 0. 67) were fabricated by depositing 100 nm LaxCa1-x MnO3 thin films on n-type silicon substrates using facing target sputtering technique. The current-voltage characteristics of the heterojunctions were measured by standard four-probe technique with different light illuminations; dark, 532 nm laser irradiation, 1064 nm laser irradiation or simulated sunlight irradiation. The results showed that the current-voltage properties presented obvious changes in the negative bias region with light illuminations. And among the three types of light irradiations which had the same optical power, under the simulated sunlight, the sample showed the largest variation of the Ⅰ- Ⅴ curve and the highest photoelectric conversion efficiency. The sample of La0.67Ca0.33MnO3/Si showed higher photoelectric conversion efficiency than the sample of La0.4Ca0.6MnO3/Si. The heterojunctions had good absorption among 400 ~ 1100 nm wavelength range shown by absorption spectrum. All the results would be helpful for exploring the solar cell material based on manganite oxide heterojunctions.%掺杂锰氧化物是一种重要功能材料,近来其光电功能特性受到重视.利用对靶溅射方法在n型硅基底上沉积了100 nm的两种镧掺杂锰氧化物薄膜LaxCa1-xMn03(x=0.4和x=0.67),构成异质结.分别研究了在无光照射、532 nm激光辐照、1064 nm激光辐照、模拟太阳光辐照4种情况下两种异质结的光生伏特效应.对比实验表明,与无光条件下相比,光照下的异质结负向区的整流特性变化明显,而正向导通区的整流曲线变化不大.其中在同样的光功率下,模拟太阳光入射时异质结I-V曲线变化最为明显,此时I-V曲线与坐标轴相交所构成的图形区域的面积也最大,光电转化效

  8. In Vivo Monosynaptic Excitatory Transmission between Layer 2 Cortical Pyramidal Neurons

    Science.gov (United States)

    Jouhanneau, Jean-Sébastien; Kremkow, Jens; Dorrn, Anja L.; Poulet, James F.A.

    2015-01-01

    Summary Little is known about the properties of monosynaptic connections between identified neurons in vivo. We made multiple (two to four) two-photon targeted whole-cell recordings from neighboring layer 2 mouse somatosensory barrel cortex pyramidal neurons in vivo to investigate excitatory monosynaptic transmission in the hyperpolarized downstate. We report that pyramidal neurons form a sparsely connected (6.7% connectivity) network with an overrepresentation of bidirectional connections. The majority of unitary excitatory postsynaptic potentials were small in amplitude (1 mV. The coefficient of variation (CV = 0.74) could largely be explained by the presence of synaptic failures (22%). Both the CV and failure rates were reduced with increasing amplitude. The mean paired-pulse ratio was 1.15 and positively correlated with the CV. Our approach will help bridge the gap between connectivity and function and allow investigations into the impact of brain state on monosynaptic transmission and integration. PMID:26670044

  9. In Vivo Monosynaptic Excitatory Transmission between Layer 2 Cortical Pyramidal Neurons

    Directory of Open Access Journals (Sweden)

    Jean-Sébastien Jouhanneau

    2015-12-01

    Full Text Available Little is known about the properties of monosynaptic connections between identified neurons in vivo. We made multiple (two to four two-photon targeted whole-cell recordings from neighboring layer 2 mouse somatosensory barrel cortex pyramidal neurons in vivo to investigate excitatory monosynaptic transmission in the hyperpolarized downstate. We report that pyramidal neurons form a sparsely connected (6.7% connectivity network with an overrepresentation of bidirectional connections. The majority of unitary excitatory postsynaptic potentials were small in amplitude (1 mV. The coefficient of variation (CV = 0.74 could largely be explained by the presence of synaptic failures (22%. Both the CV and failure rates were reduced with increasing amplitude. The mean paired-pulse ratio was 1.15 and positively correlated with the CV. Our approach will help bridge the gap between connectivity and function and allow investigations into the impact of brain state on monosynaptic transmission and integration.

  10. Neurofilament light mutation causes hereditary motor and sensory neuropathy with pyramidal signs.

    Science.gov (United States)

    Hashiguchi, Akihiro; Higuchi, Yujiro; Nomura, Miwa; Nakamura, Tomonori; Arata, Hitoshi; Yuan, Junhui; Yoshimura, Akiko; Okamoto, Yuji; Matsuura, Eiji; Takashima, Hiroshi

    2014-12-01

    To identify novel mutations causing hereditary motor and sensory neuropathy (HMSN) with pyramidal signs, a variant of Charcot-Marie-Tooth disease (CMT), we screened 28 CMT and related genes in four members of an affected Japanese family. Clinical features included weakness of distal lower limb muscles, foot deformity, and mild sensory loss, then late onset of progressive spasticity. Electrophysiological studies revealed widespread neuropathy. Electron microscopic analysis showed abnormal mitochondria and mitochondrial accumulation in the neurons and Schwann cells. Brain magnetic resonance imaging (MRI) revealed an abnormally thin corpus callosum. In all four, microarrays detected a novel heterozygous missense mutation c.1166A>G (p.Y389C) in the gene encoding the light-chain neurofilament protein (NEFL), indicating that NEFL mutations can result in a HMSN with pyramidal signs phenotype. PMID:25583183

  11. Dielectrophoresis-Assisted Raman Spectroscopy of Intravesicular Analytes on Metallic Pyramids.

    Science.gov (United States)

    Barik, Avijit; Cherukulappurath, Sudhir; Wittenberg, Nathan J; Johnson, Timothy W; Oh, Sang-Hyun

    2016-02-01

    Chemical analysis of membrane-bound containers such as secretory vesicles, organelles, and exosomes can provide insights into subcellular biology. These containers are loaded with a range of important biomolecules, which further underscores the need for sensitive and selective analysis methods. Here we present a metallic pyramid array for intravesicular analysis by combining site-selective dielectrophoresis (DEP) and Raman spectroscopy. Sharp pyramidal tips act as a gradient force generator to trap nanoparticles or vesicles from the solution, and the tips are illuminated by a monochromatic light source for concurrent spectroscopic detection of trapped analytes. The parameters suitable for DEP trapping were optimized by fluorescence microscopy, and the Raman spectroscopy setup was characterized by a nanoparticle based model system. Finally, vesicles loaded with 4-mercaptopyridine were concentrated at the tips and their Raman spectra were detected in real time. These pyramidal tips can perform large-area array-based trapping and spectroscopic analysis, opening up possibilities to detect molecules inside cells or cell-derived vesicles. PMID:26751756

  12. Opposite monosynaptic scaling of BLP-vCA1 inputs governs hopefulness- and helplessness-modulated spatial learning and memory.

    Science.gov (United States)

    Yang, Ying; Wang, Zhi-Hao; Jin, Sen; Gao, Di; Liu, Nan; Chen, Shan-Ping; Zhang, Sinan; Liu, Qing; Liu, Enjie; Wang, Xin; Liang, Xiao; Wei, Pengfei; Li, Xiaoguang; Li, Yin; Yue, Chenyu; Li, Hong-Lian; Wang, Ya-Li; Wang, Qun; Ke, Dan; Xie, Qingguo; Xu, Fuqiang; Wang, Liping; Wang, Jian-Zhi

    2016-01-01

    Different emotional states lead to distinct behavioural consequences even when faced with the same challenging events. Emotions affect learning and memory capacities, but the underlying neurobiological mechanisms remain elusive. Here we establish models of learned helplessness (LHL) and learned hopefulness (LHF) by exposing animals to inescapable foot shocks or with anticipated avoidance trainings. The LHF animals show spatial memory potentiation with excitatory monosynaptic upscaling between posterior basolateral amygdale (BLP) and ventral hippocampal CA1 (vCA1), whereas the LHL show memory deficits with an attenuated BLP-vCA1 connection. Optogenetic disruption of BLP-vCA1 inputs abolishes the effects of LHF and impairs synaptic plasticity. By contrast, targeted BLP-vCA1 stimulation rescues the LHL-induced memory deficits and mimics the effects of LHF. BLP-vCA1 stimulation increases synaptic transmission and dendritic plasticity with the upregulation of CREB and intrasynaptic AMPA receptors in CA1. These findings indicate that opposite excitatory monosynaptic scaling of BLP-vCA1 controls LHF- and LHL-modulated spatial memory, revealing circuit-specific mechanisms linking emotions to memory. PMID:27411738

  13. PYRAMIDAL-HOLLOW-BEAM DIPOLE TRAP FOR ALKALI ATOMS

    Institute of Scientific and Technical Information of China (English)

    YIN JIAN-PING; GAO WEI-JIAN; WANG YU-ZHU; ZHU YI-FU; WANG YI-QIU

    2000-01-01

    We propose a dark gravito-optical dipole trap, for alkali atoms, consisting of a blue-detuned, pyramidal-hollow laser beam propagating upward and the gravity field. When cold atoms from a magneto-optical trap are loaded into the pyramidal-hollow beam and bounce inside the pyramidal-hollow beam, they experience efficient Sisyphus cooling and geometric cooling induced by the pyramidal-hollow beam and the weak repumping beam propagating downward. Our study shows that an ultracold and dense atomic sample with an equilibrium 3D momentum of ~ 3hk and an atomic density above the point of Bose-Einstein condensation may be obtained in this pure optical trap.

  14. The Fishery of Truckee River and Pyramid Lake, Nevada

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report provides an overview of the Washoe Project Act. Trout populations in Pyramid Lake began to decline in the 1930s due to poor water quality and poor...

  15. The Personal Marketing Pyramid: A Model for Secretarial Success.

    Science.gov (United States)

    Caudill, Donald W.

    1988-01-01

    The author describes his model of a synergistic approach to achieving success. His Personal Marketing Pyramid consists of four sciences: physiology, psychology, sociology, and philosophy. He uses examples related to success in a secretarial career. (CH)

  16. Fixing the Pole in the Pyramid

    CERN Document Server

    Banks, Tom; Kathrein, Scott

    2009-01-01

    We revisit the problem of the hidden sector Landau pole in the Pyramid Scheme. There is a fixed line in the plane of hidden sector gauge coupling and a Yukawa coupling between the trianon fields. We postulate that the couplings flow to this line, at a point where the hidden sector gauge coupling is close to the strong coupling edge of its perturbative regime. Below the masses of the heavier trianons, the model quickly flows to a confining N_F=N_C=3 supersymmetric gauge theory, as required by phenomenological considerations. We study possible discrete R-symmetries, which guarantee, among other things, that the basin of attraction of the fixed line has full co-dimension in the space of R-allowed couplings. The Yukawa couplings required to get the fixed line violate the pyrma-baryon symmetries we invoked in previous work to find a dark matter candidate. Omitting one of them, we have a dark matter candidate, and an acceptable RG flow down from the unification scale, if the confinement scale of the hidden sector g...

  17. Investigation of flow and pressure characteristics around pyramidal buildings

    OpenAIRE

    Ikhwan, Muhammad

    2005-01-01

    Pyramidal buildings are undergoing a renaissance in todays architectural design due to their attractive mystery that has fascinated many architects. From an aerodynamic engineering point of view, structural buildings with the shape of a pyramid have their own interesting and particular aerodynamic characteristics as compared to other usual structural buildings (i.e. cuboidal). However, despite its distinct aerodynamic characteristics compared to other usual structural buildings, the flow a...

  18. Searching for Chambers and Caves in Teotihuacan's Sun Pyramid

    International Nuclear Information System (INIS)

    In this work a status report of a search for caves in the Sun pyramid in Teotihuacan, Mexico is presented. From an archeological perspective the main goal is to gather evidence to determine whether the pyramid was a state or a funerary temple. The general layout of the detector that is being built is an updated version of the one originally proposed by Alvarez et al.

  19. Pyramidal micro-mirrors for microsystems and atom chips

    CERN Document Server

    Trupke, M; Curtis, E A; Ashmore, J P; Eriksson, S; Hinds, E A; Moktadir, Z; Gollasch, C; Kraft, M; Prakash, G V; Baumberg, J J

    2005-01-01

    Concave pyramids are created in the (100) surface of a silicon wafer by anisotropic etching in potassium hydroxide. High quality micro-mirrors are then formed by sputtering gold onto the smooth silicon (111) faces of the pyramids. These mirrors show great promise as high quality optical devices suitable for integration into MOEMS and atom chips. We have shown that structures of this shape can be used to laser-cool and hold atoms in a magneto-optical trap.

  20. Multiresolution maximum intensity volume rendering by morphological adjunction pyramids

    OpenAIRE

    Roerdink, Jos B. T. M.

    2003-01-01

    We describe a multiresolution extension to maximum intensity projection (MIP) volume rendering, allowing progressive refinement and perfect reconstruction. The method makes use of morphological adjunction pyramids. The pyramidal analysis and synthesis operators are composed of morphological 3-D erosion and dilation, combined with dyadic downsampling for analysis and dyadic upsampling for synthesis. In this case the MIP operator can be interchanged with the synthesis operator. This fact is the...

  1. Mechanical Control of Graphene on Engineered Pyramidal Strain Arrays

    OpenAIRE

    Gill, Stephen T.; Hinnefeld, John H.; Zhu, Shuze; Swanson, William T.; Li, Teng; Mason, Nadya

    2015-01-01

    Strain can tune desirable electronic behavior in graphene, but there has been limited progress in controlling strain in graphene devices. In this paper, we study the mechanical response of graphene on substrates patterned with arrays of mesoscale pyramids. Using atomic force microscopy, we demonstrate that the morphology of graphene can be controlled from conformal to suspended depending on the arrangement of pyramids and the aspect ratio of the array. Non-uniform strains in graphene suspende...

  2. Multiresolution Maximum Intensity Volume Rendering by Morphological Pyramids

    OpenAIRE

    Roerdink, Jos B. T. M.; Ebert, D.; Favre, JM; Peikert, R.

    2001-01-01

    We propose a multiresolution representation for maximum intensity projection (MIP) volume rendering, based on morphological pyramids which allow progressive refinement and have the property of perfect reconstruction. The pyramidal analysis and synthesis operators are composed of morphological erosion and dilation, combined with dyadic downsampling for analysis and dyadic upsampling for synthesis. The structure of the multiresolution MIP representation is very similar to wavelet splatting, the...

  3. ASTRONOMICAL ALGORITHMS OF EGYPTIAN PYRAMIDS SLOPES AND THEIR MODULES DIVIDER

    OpenAIRE

    Aboulfotouh, Hossam M. K.

    2015-01-01

    This paper is an attempt to show the astronomical design principles that are encoded in the geometrical forms of the largest five pyramids of the fourth Egyptian dynasty, in Giza and Dahshur plateaus, based on using the pyramids’ design-modules that are mentioned in the so-called Rhind Mathematical Papyrus. It shows the astronomical algorithms for quantifying the slopes of pyramids, with reference to specific range of earth’s axial tilt, within spherical co-ordinates system. Besid...

  4. Searching for Chambers and Caves in Teotihuacan's Sun Pyramid

    Science.gov (United States)

    Alfaro, R.; Arrieta, E.; Barba P., L.; Becerril, A. D.; Belmont, E.; Carrillo, I.; Cabrera M., J. I.; Esquivel, O.; Grabski, V.; López R., J. M.; Manzanilla N., L.; Martínez D., A.; Menchaca R., A.; Moreno, M.; Núñez C., R.; Plascencia, J. C.; Rangel, M.; Villoro, M.

    2003-06-01

    In this work a status report of a search for caves in the Sun pyramid in Teotihuacan, México is presented. From an archeological perspective the main goal is to gather evidence to determine whether the pyramid was a state or a funerary temple. The general layout of the detector that is being built is an updated version of the one originally proposed by Alvarez et al..

  5. Layer 5 Pyramidal Neurons’ Dendritic Remodeling and Increased Microglial Density in Primary Motor Cortex in a Murine Model of Facial Paralysis

    Directory of Open Access Journals (Sweden)

    Diana Urrego

    2015-01-01

    Full Text Available This work was aimed at characterizing structural changes in primary motor cortex layer 5 pyramidal neurons and their relationship with microglial density induced by facial nerve lesion using a murine facial paralysis model. Adult transgenic mice, expressing green fluorescent protein in microglia and yellow fluorescent protein in projecting neurons, were submitted to either unilateral section of the facial nerve or sham surgery. Injured animals were sacrificed either 1 or 3weeks after surgery. Two-photon excitation microscopy was then used for evaluating both layer 5 pyramidal neurons and microglia in vibrissal primary motor cortex (vM1. It was found that facial nerve lesion induced long-lasting changes in the dendritic morphology of vM1 layer 5 pyramidal neurons and in their surrounding microglia. Dendritic arborization of the pyramidal cells underwent overall shrinkage. Apical dendrites suffered transient shortening while basal dendrites displayed sustained shortening. Moreover, dendrites suffered transient spine pruning. Significantly higher microglial cell density was found surrounding vM1 layer 5 pyramidal neurons after facial nerve lesion with morphological bias towards the activated phenotype. These results suggest that facial nerve lesions elicit active dendrite remodeling due to pyramidal neuron and microglia interaction, which could be the pathophysiological underpinning of some neuropathic motor sequelae in humans.

  6. The temporoammonic input to the hippocampal CA1 region displays distinctly different synaptic plasticity compared to the Schaffer collateral input in vivo: significance for synaptic information processing

    Directory of Open Access Journals (Sweden)

    Ayla eAksoy Aksel

    2013-08-01

    Full Text Available In terms of its sub-regional differentiation, the hippocampal CA1 region receives cortical information directly via the perforant (temporoammonic path (pp-CA1 synapse and indirectly via the tri-synaptic pathway where the last relay station is the Schaffer collateral-CA1 synapse (Sc-CA1 synapse. Research to date on pp-CA1 synapses has been conducted predominantly in vitro and never in awake animals, but these studies hint that information processing at this synapse might be distinct to processing at the Sc-CA1 synapse. Here, we characterized synaptic properties and synaptic plasticity at the pp-CA1 synapse of freely behaving adult rats. We established that field excitatory postsynaptic potentials at the pp-CA1 have longer onset latencies and a shorter time-to-peak compared to the Sc-CA1 synapse. LTP (> 24h was successfully evoked by tetanic afferent stimulation of pp-CA1 synapses. Low frequency stimulation evoked synaptic depression at Sc-CA1 synapses, but did not elicit LTD at pp-CA1 synapses unless the Schaffer collateral afferents to the CA1 region had been severed. Paired-pulse responses also showed significant differences. Our data suggest that synaptic plasticity at the pp-CA1 synapse is distinct from the Sc-CA1 synapse and that this may reflect its specific role in hippocampal information processing.

  7. Controlled growth of hexagonal GaN pyramids by hot-wall MOCVD

    OpenAIRE

    Lundskog, Anders; Hsu, Chih-Wei; Nilsson, Daniel; Karlsson, K. Fredrik; Forsberg, Urban; Holtz, Per-Olof; Janzén, Erik

    2013-01-01

    Hexagonal GaN pyramids have been fabricated by hot-wall metal organic chemical vapor deposition (hot-wall MOCVD) and the growth evolution have been studied. It was concluded that the pyramid growth can be divided into two regimes separated by the adsorption kinetics of the {1101} surfaces of the pyramids. In the adsorption regime, the pyramids grow simultaneously in the <1101> and [0001] -directions. In the zero-adsorption regime the pyramids grow only in the [0001] direction. Thus the ...

  8. Molecular evidence of synaptic pathology in the CA1 region in schizophrenia

    Science.gov (United States)

    Matosin, Natalie; Fernandez-Enright, Francesca; Lum, Jeremy S; Engel, Martin; Andrews, Jessica L; Gassen, Nils C; Wagner, Klaus V; Schmidt, Mathias V; Newell, Kelly A

    2016-01-01

    Alterations of postsynaptic density (PSD)95-complex proteins in schizophrenia ostensibly induce deficits in synaptic plasticity, the molecular process underlying cognitive functions. Although some PSD95-complex proteins have been previously examined in the hippocampus in schizophrenia, the status of other equally important molecules is unclear. This is especially true in the cornu ammonis (CA)1 hippocampal subfield, a region that is critically involved in the pathophysiology of the illness. We thus performed a quantitative immunoblot experiment to examine PSD95 and several of its associated proteins in the CA1 region, using post mortem brain samples derived from schizophrenia subjects with age-, sex-, and post mortem interval-matched controls (n=20/group). Our results indicate a substantial reduction in PSD95 protein expression (−61.8%). Further analysis showed additional alterations to the scaffold protein Homer1 (Homer1a: +42.9%, Homer1b/c: −24.6%), with a twofold reduction in the ratio of Homer1b/c:Homer1a isoforms (P=0.011). Metabotropic glutamate receptor 1 (mGluR1) protein levels were significantly reduced (−32.7%), and Preso, a protein that supports interactions between Homer1 or PSD95 with mGluR1, was elevated (+83.3%). Significant reduction in synaptophysin (−27.8%) was also detected, which is a validated marker of synaptic density. These findings support the presence of extensive molecular abnormalities to PSD95 and several of its associated proteins in the CA1 region in schizophrenia, offering a small but significant step toward understanding how proteins in the PSD are altered in the schizophrenia brain, and their relevance to overall hippocampal and cognitive dysfunction in the illness. PMID:27430010

  9. Overexpression of SIRT6 in the hippocampal CA1 impairs the formation of long-term contextual fear memory.

    Science.gov (United States)

    Yin, Xi; Gao, Yuan; Shi, Hai-Shui; Song, Li; Wang, Jie-Chao; Shao, Juan; Geng, Xu-Hong; Xue, Gai; Li, Jian-Li; Hou, Yan-Ning

    2016-01-01

    Histone modifications have been implicated in learning and memory. Our previous transcriptome data showed that expression of sirtuins 6 (SIRT6), a member of Histone deacetylases (HDACs) family in the hippocampal cornu ammonis 1 (CA1) was decreased after contextual fear conditioning. However, the role of SIRT6 in the formation of memory is still elusive. In the present study, we found that contextual fear conditioning inhibited translational expression of SIRT6 in the CA1. Microinfusion of lentiviral vector-expressing SIRT6 into theCA1 region selectively enhanced the expression of SIRT6 and impaired the formation of long-term contextual fear memory without affecting short-term fear memory. The overexpression of SIRT6 in the CA1 had no effect on anxiety-like behaviors or locomotor activity. Also, we also found that SIRT6 overexpression significantly inhibited the expression of insulin-like factor 2 (IGF2) and amounts of proteins and/or phosphoproteins (e.g. Akt, pAkt, mTOR and p-mTOR) related to the IGF2 signal pathway in the CA1. These results demonstrate that the overexpression of SIRT6 in the CA1 impaired the formation of long-term fear memory, and SIRT6 in the CA1 may negatively modulate the formation of contextual fear memory via inhibiting the IGF signaling pathway. PMID:26732053

  10. Pyramid wavefront sensor for image quality evaluation of optical system

    Science.gov (United States)

    Chen, Zhendong

    2015-08-01

    When the pyramid wavefront sensor is used to evaluate the imaging quality, placed at the focal plane of the aberrated optical system e.g., a telescope, it splits the light into four beams. Four images of the pupil are created on the detector and the detection signals of the pyramid wavefront sensor are calculated with these four intensity patterns, providing information on the derivatives of the aberrated wavefront. Based on the theory of the pyramid wavefront sensor, we are going to develop simulation software and a wavefront detector which can be used to test the imaging quality of the telescope. In our system, the subpupil image intensity through the pyramid sensor is calculated to obtain the aberration of wavefront where the piston, tilt, defocus, spherical, coma, astigmatism and other high level aberrations are separately represented by Zernike polynomials. The imaging quality of the optical system is then evaluated by the subsequent wavefront reconstruction. The performance of our system is to be checked by comparing with the measurements carried out using Puntino wavefront instrument (the method of SH wavefront sensor). Within this framework, the measurement precision of pyramid sensor will be discussed as well through detailed experiments. In general, this project would be very helpful both in our understanding of the principle of the wavefront reconstruction and its future technical applications. So far, we have produced the pyramid and established the laboratory setup of the image quality detecting system based on this wavefront sensor. Preliminary results are obtained, in that we have obtained the intensity images of the four pupils. Additional work is needed to analyze the characteristics of the pyramid wavefront sensor.

  11. Intraoperative tractography and neuronavigation of the pyramidal tract

    International Nuclear Information System (INIS)

    Diffusion tensor imaging (DTI) based fiber tracking was applied to visualize the course of the pyramidal tract in the surgical field by microscope-based navigation. In 70 patients with lesions adjacent to the pyramidal tract, DTI data were integrated in a navigational setup. Diffusion data (b=0) were rigidly registered with standard T1-weighted 3-D images. Fiber tracking was performed applying a tensor-deflection algorithm using a multiple volume of interest approach as seed regions for tracking. fMRI data identifying the motor gyrus were applied as selection criteria to define the fibers of interest. After tracking, a 3-D object was generated representing the pyramidal tract. In selected cases, the intraoperative image data (1.5 T intraoperative MRI) were used to update the navigation system. In all patients the pyramidal tract could be visualized in the operative field applying the heads-up display of the operating microscope. In 8 patients (11%) a new or aggravated postoperative paresis could be observed, which was transient in 5 of them; thus, only in 3 patients (4.2%) was there a new permanent neurological deficit. Intraoperative imaging depicted a shifting of the pyramidal tract which amounted up to 15 mm; even the direction of shifting was variable and could not be predicted before surgery, so that mathematical models trying to predict brain shift behaviour are of restricted value only. DTI fiber tracking data can be reliably integrated into navigational systems providing intraoperative visualization of the pyramidal tract. This technique allowed the resection of lesions adjacent to the pyramidal tract with low morbidity. (author)

  12. CA1-specific deletion of NMDA receptors induces abnormal renewal of a learned fear response.

    Science.gov (United States)

    Hirsch, Silke J; Regmi, Nanda L; Birnbaum, Shari G; Greene, Robert W

    2015-11-01

    CA1 hippocampal N-methyl-d-aspartate-receptors (NMDARs) are necessary for contextually related learning and memory processes. Extinction, a form of learning, has been shown to require intact hippocampal NMDAR signalling. Renewal of fear expression can occur after fear extinction training, when the extinguished fear stimulus is presented in an environmental context different from the training context and thus, renewal is dependent on contextual memory. In this study, we show that a Grin1 knock-out (loss of the essential NR1 subunit for the NMDAR) restricted to the bilateral CA1 subfield of the dorsal hippocampus does not affect acquisition of learned fear, but does attenuate extinction of a cued fear response even when presented in the extinction-training context. We propose that failure to remember the (safe) extinction context is responsible for the abnormal fear response and suggest it is a dysfunctional renewal. The results highlight the difference in outcome of extinguished fear memory resulting from a partial rather than complete loss of function of the hippocampus and suggest a potential mechanism for abnormally increased fear expression in PTSD. PMID:25786918

  13. Pycnogenol protects CA3-CA1 synaptic function in a rat model of traumatic brain injury.

    Science.gov (United States)

    Norris, Christopher M; Sompol, Pradoldej; Roberts, Kelly N; Ansari, Mubeen; Scheff, Stephen W

    2016-02-01

    Pycnogenol (PYC) is a patented mix of bioflavonoids with potent anti-oxidant and anti-inflammatory properties. Previously, we showed that PYC administration to rats within hours after a controlled cortical impact (CCI) injury significantly protects against the loss of several synaptic proteins in the hippocampus. Here, we investigated the effects of PYC on CA3-CA1 synaptic function following CCI. Adult Sprague-Dawley rats received an ipsilateral CCI injury followed 15 min later by intravenous injection of saline vehicle or PYC (10 mg/kg). Hippocampal slices from the injured (ipsilateral) and uninjured (contralateral) hemispheres were prepared at seven and fourteen days post-CCI for electrophysiological analyses of CA3-CA1 synaptic function and induction of long-term depression (LTD). Basal synaptic strength was impaired in slices from the ipsilateral, relative to the contralateral, hemisphere at seven days post-CCI and susceptibility to LTD was enhanced in the ipsilateral hemisphere at both post-injury timepoints. No interhemispheric differences in basal synaptic strength or LTD induction were observed in rats treated with PYC. The results show that PYC preserves synaptic function after CCI and provides further rationale for investigating the use of PYC as a therapeutic in humans suffering from neurotrauma. PMID:26607913

  14. Cytomorphometric changes in hippocampal CA1 neurons exposed to simulated microgravity using rats as model

    Directory of Open Access Journals (Sweden)

    Amit Ranjan

    2014-05-01

    Full Text Available Microgravity and sleep loss lead to cognitive and learning deficits. These behavioral alterations are likely to be associated with cytomorphological changes and loss of neurons. To understand the phenomenon, we exposed rats (225-275g to 14 days simulated microgravity (SMg and compared its effects on CA1 hippocampal neuronal plasticity, with that of normal cage control rats. We observed that the mean area, perimeter, synaptic cleft and length of active zone of CA1 hippocampal neurons significantly decreased while dendritic arborization and number of spines significantly increased in SMg group as compared with controls. The mean thickness of the post synaptic density and total dendritic length remained unaltered. The changes may be a compensatory effect induced by exposure to microgravity; however, the effects may be transient or permanent, which need further study. These findings may be useful for designing effective prevention for those, including the astronauts, exposed to microgravity. Further, subject to confirmation we propose that SMg exposure might be useful for recovery of stroke patients.

  15. Ripple-associated high-firing interneurons in the hippocampal CA1 region

    Institute of Scientific and Technical Information of China (English)

    WANG Ying; ZHANG Lu; PAN JingWei; XIE Kun; LI ShiQi; WANG ZhiRu; LIN LongNian

    2008-01-01

    By simultaneously recording the activity of individual neurons and field potentials in freely behaving mice, we found two types of interneurons firing at high frequency in the hippocampal CA1 region,which had high correlations with characteristic sharp wave-associated ripple oscillations (100-250 Hz)during slow-wave sleep. The firing of these two types of interneurons highly synchronized with ripple oscillations during slow-wave sleep, with strongly increased firing rates corresponding to individual ripple episodes. Interneuron type Ⅰ had at most one spike in each sub-ripple cycle of ripple episodes and the peak firing rate was 310±33.17 Hz. Interneuron type Ⅱ had one or two spikes in each sub-ripple cycle and the peak firing rate was 410±47.61 Hz. During active exploration, their firing was phase locked to theta oscillations with the highest probability at the trough of theta wave. Both two types of interneurons increased transiently their firing rates responding to the startling shake stimuli. The results showed that these two types of high-frequency interneurone in the hippocsmpal CA1 region were involved in the modulation of the hippocampal neural network during different states.

  16. Ripple-associated high-firing interneurons in the hippocampal CA1 region

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    By simultaneously recording the activity of individual neurons and field potentials in freely behaving mice, we found two types of interneurons firing at high frequency in the hippocampal CA1 region, which had high correlations with characteristic sharp wave-associated ripple oscillations (100―250 Hz) during slow-wave sleep. The firing of these two types of interneurons highly synchronized with ripple oscillations during slow-wave sleep, with strongly increased firing rates corresponding to individual ripple episodes. Interneuron type I had at most one spike in each sub-ripple cycle of ripple episodes and the peak firing rate was 310±33.17 Hz. Interneuron type II had one or two spikes in each sub-ripple cycle and the peak firing rate was 410±47.61 Hz. During active exploration, their firing was phase locked to theta oscillations with the highest probability at the trough of theta wave. Both two types of interneurons increased transiently their firing rates responding to the startling shake stimuli. The results showed that these two types of high-frequency interneurons in the hippocampal CA1 region were involved in the modulation of the hippocampal neural network during different states.

  17. The GLP-1 Receptor Agonist Liraglutide Improves Memory Function and Increases Hippocampal CA1 Neuronal Numbers in a Senescence-Accelerated Mouse Model of Alzheimer’s Disease

    Science.gov (United States)

    Hansen, Henrik H.; Fabricius, Katrine; Barkholt, Pernille; Niehoff, Michael L.; Morley, John E.; Jelsing, Jacob; Pyke, Charles; Knudsen, Lotte Bjerre; Farr, Susan A.; Vrang, Niels

    2015-01-01

    Abstract Recent studies indicate that glucagon-like peptide 1 (GLP-1) receptor agonists, currently used in the management of type 2 diabetes, exhibit neurotrophic and neuroprotective effects in amyloid-β (Aβ) toxicity models of Alzheimer’s disease (AD). We investigated the potential pro-cognitive and neuroprotective effects of the once-daily GLP-1 receptor agonist liraglutide in senescence-accelerated mouse prone 8 (SAMP8) mice, a model of age-related sporadic AD not dominated by amyloid plaques. Six-month-old SAMP8 mice received liraglutide (100 or 500 μg/kg/day, s.c.) or vehicle once daily for 4 months. Vehicle-dosed age-matched 50% back-crossed as well as untreated young (4-month-old) SAMP8 mice were used as control groups for normal memory function. Vehicle-dosed 10-month-old SAMP8 mice showed significant learning and memory retention deficits in an active-avoidance T-maze, as compared to both control groups. Also, 10-month-old SAMP8 mice displayed no immunohistological signatures of amyloid-β plaques or hyperphosphorylated tau, indicating the onset of cognitive deficits prior to deposition of amyloid plaques and neurofibrillary tangles in this AD model. Liraglutide significantly increased memory retention and total hippocampal CA1 pyramidal neuron numbers in SAMP8 mice, as compared to age-matched vehicle-dosed SAMP8 mice. In conclusion, liraglutide delayed or partially halted the progressive decline in memory function associated with hippocampal neuronal loss in a mouse model of pathological aging with characteristics of neurobehavioral and neuropathological impairments observed in early-stage sporadic AD. PMID:25869785

  18. The GLP-1 Receptor Agonist Liraglutide Improves Memory Function and Increases Hippocampal CA1 Neuronal Numbers in a Senescence-Accelerated Mouse Model of Alzheimer's Disease.

    Science.gov (United States)

    Hansen, Henrik H; Fabricius, Katrine; Barkholt, Pernille; Niehoff, Michael L; Morley, John E; Jelsing, Jacob; Pyke, Charles; Knudsen, Lotte Bjerre; Farr, Susan A; Vrang, Niels

    2015-01-01

    Recent studies indicate that glucagon-like peptide 1 (GLP-1) receptor agonists, currently used in the management of type 2 diabetes, exhibit neurotrophic and neuroprotective effects in amyloid-β (Aβ) toxicity models of Alzheimer's disease (AD). We investigated the potential pro-cognitive and neuroprotective effects of the once-daily GLP-1 receptor agonist liraglutide in senescence-accelerated mouse prone 8 (SAMP8) mice, a model of age-related sporadic AD not dominated by amyloid plaques. Six-month-old SAMP8 mice received liraglutide (100 or 500 μg/kg/day, s.c.) or vehicle once daily for 4 months. Vehicle-dosed age-matched 50% back-crossed as well as untreated young (4-month-old) SAMP8 mice were used as control groups for normal memory function. Vehicle-dosed 10-month-old SAMP8 mice showed significant learning and memory retention deficits in an active-avoidance T-maze, as compared to both control groups. Also, 10-month-old SAMP8 mice displayed no immunohistological signatures of amyloid-β plaques or hyperphosphorylated tau, indicating the onset of cognitive deficits prior to deposition of amyloid plaques and neurofibrillary tangles in this AD model. Liraglutide significantly increased memory retention and total hippocampal CA1 pyramidal neuron numbers in SAMP8 mice, as compared to age-matched vehicle-dosed SAMP8 mice. In conclusion, liraglutide delayed or partially halted the progressive decline in memory function associated with hippocampal neuronal loss in a mouse model of pathological aging with characteristics of neurobehavioral and neuropathological impairments observed in early-stage sporadic AD. PMID:25869785

  19. BN-coated Ca1−xSrxS:Eu solid-solution nanowires with tunable red light emission

    International Nuclear Information System (INIS)

    We report on the controlled growth of novel BN-coated Ca1−xSrxS:Eu nanowires via a solid–liquid–solid process. The Ca1−xSrxS solid solution forms as one-dimensional nanowires and has been coated with homogeneous protective BN nanolayers. The structure and luminescence properties of this new nanocomposite have been systematically investigated. High-spatial-resolution cathodoluminescence investigations reveal that effective red color tuning has been achieved by tailoring the composition of the Ca1−xSrxS nanowires. Moreover, codoping of Ce3+ and Eu2+ in the CaS nanowire can induce energy transfer in the matrix and make it possible to obtain enhanced orange color in the nanowires. The BN-coated Ca1−xSrxS:Eu solid-solution nanowires are envisaged to be valuable red-emitting nanophosphors and useful in advanced nanodevices and white LEDs. (paper)

  20. Pyramidal ice crystal scattering phase functions and concentric halos

    Directory of Open Access Journals (Sweden)

    C. Liu

    Full Text Available Phase functions have been calculated using the Monte Carlo/geometric ray tracing method for single hexagonal pyramidal ice crystals (such as solid and hollow bullets randomly oriented in space and horizontal plane, in order to study the concentric halo formations. Results from three dimensional model calculations show that 9° halo can be as bright as the common 22° halo for pyramidal angle of 28°, and the 18°, 20°, 24° and 35° halos cannot be seen due to the strong 22° halo domination in the scattering phase function between 18° and 35°. For solid pyramidal ice crystals randomly oriented horizontally, the 35° arc can be produced and its intensity depends on the incident ray solar angle and the particle aspect ratio.

  1. A study of correlation technique on pyramid processed images

    Indian Academy of Sciences (India)

    M Sankar Kishore; K Veerabhadra Rao

    2000-02-01

    The pyramid algorithm is potentially a powerful tool for advanced television image processing and for pattern recognition. An attempt is made to design and develop both hardware and software for a system which performs decomposition and reconstruction of digitized images by implementing the Burt pyramid algorithm. In this work, an attempt is also made to study correlation performance on reconstructed images. That is, the reference image is taken from the original image and correlation is performed on expanded images of the same size. Similarly, correlation performance study is carried out on different pyramid- processed levels. In this paper results are presented in terms of RMS error between original and expanded images. Only still images are considered, and the hardware is designed around an i486 processor and software is developed in PL/M 86.

  2. Solid state synthesis and structural refinement of polycrystalline LaCa1-TiO3 ceramic powder

    Indian Academy of Sciences (India)

    O P Shrivastava; Narendra Kumar; I B Sharma

    2004-04-01

    Perovskite structure based ceramic precursors have a characteristic property of substitution in the ``A" site of the ABO3 structure. This makes them a potential material for nuclear waste management in synthetic rock (SYNROC) technology. In order to simulate the mechanism of rare earth fixation in perovskite, La Ca1-TiO3 (where = 0.05) has been synthesized through ceramic route by taking calculated quantities of oxides of Ca, Ti and La as starting materials. Solid state synthesis has been carried out by repeated pelletizing and sintering the finely powdered oxide mixture in a muffle furnace at 1050°C. The ceramic phase has been characterized by its powder diffraction pattern. Step analysis data has been used to determine the structure of solid solution of lanthanum substituted calcium titanate. The SEM and EDAX analyses also confirm that the CaTiO3 can act as a host for lanthanum. X-ray data has been interpreted using CRYSFIRE and POWDERCELL softwares. The ℎ, , values for different lattice planes have been generated from the experimental data. The lanthanum substituted perovskite crystallizes in orthorhombic symmetry with space group (#62). Following unit cell parameters have been calculated: = 5.410, = 7.631, = 5.382. The calculated and observed values of corresponding intensities, 2, and density show good agreement. GSAS based calculation for bond distances Ti–O, Ca–O, La–O and bond angles Ti–O–Ca, Ca–O–Ca, La–O–Ti have been reported.

  3. Space Station view of the Pyramids at Giza

    Science.gov (United States)

    2002-01-01

    One of the world's most famous archaeological sites has been photographed in amazing detail by the astronauts onboard Space Station Alpha. This image, taken 15 August, 2001, represents the greatest detail of the Giza plateau captured from a human-occupied spacecraft (approximate 7 m resolution). Afternoon sun casts shadows that help the eye make out the large pyramids of Khufu, Khafre and Menkaure. Sets of three smaller queens' pyramids can be seen to the east of the Pyramid of Khufu and south of the Pyramid of Menkaure. The light-colored causeway stretching from the Mortuary Temple at the Pyramid of Khafre to the Valley Temple near the Sphinx (arrow) can also be seen. Because it is not tall enough to cast a deep shadow, the Sphinx itself cannot readily be distinguished. Although some commercial satellites, such as IKONOS, have imaged the Pyramids at Giza in greater detail (1 m resolution), this image highlights the potential of the International Space Station as a remote sensing platform. A commercial digital camera without space modifications was used to obtain this picture. Similarly, a variety of remote sensing instruments developed for use on aircraft can potentially be used from the Space Station. Currently, all photographs of Earth taken by astronauts from the Space Shuttle and Space Station are released to the public for scientific and educational benefit and can be accessed on the World Wide Web through the NASA-JSC Gateway to Astronaut Photography of Earth (http://eol/jsc.nasa.gov/sseop). Image ISS003-ESC-5120 was provided by the Earth Sciences and Image Analysis Laboratory at Johnson Space Center (http://eol.jsc.nasa.gov).

  4. Hippocampal CA1 transcriptional profile of sleep deprivation: relation to aging and stress.

    Directory of Open Access Journals (Sweden)

    Nada M Porter

    Full Text Available BACKGROUND: Many aging changes seem similar to those elicited by sleep-deprivation and psychosocial stress. Further, sleep architecture changes with age suggest an age-related loss of sleep. Here, we hypothesized that sleep deprivation in young subjects would elicit both stress and aging-like transcriptional responses. METHODOLOGY/PRINCIPAL FINDINGS: F344 rats were divided into control and sleep deprivation groups. Body weight, adrenal weight, corticosterone level and hippocampal CA1 transcriptional profiles were measured. A second group of animals was exposed to novel environment stress (NES, and their hippocampal transcriptional profiles measured. A third cohort exposed to control or SD was used to validate transcriptional results with Western blots. Microarray results were statistically contrasted with prior transcriptional studies. Microarray results pointed to sleep pressure signaling and macromolecular synthesis disruptions in the hippocampal CA1 region. Animals exposed to NES recapitulated nearly one third of the SD transcriptional profile. However, the SD-aging relationship was more complex. Compared to aging, SD profiles influenced a significant subset of genes. mRNA associated with neurogenesis and energy pathways showed agreement between aging and SD, while immune, glial, and macromolecular synthesis pathways showed SD profiles that opposed those seen in aging. CONCLUSIONS/SIGNIFICANCE: We conclude that although NES and SD exert similar transcriptional changes, selective presynaptic release machinery and Homer1 expression changes are seen in SD. Among other changes, the marked decrease in Homer1 expression with age may represent an important divergence between young and aged brain response to SD. Based on this, it seems reasonable to conclude that therapeutic strategies designed to promote sleep in young subjects may have off-target effects in the aged. Finally, this work identifies presynaptic vesicular release and intercellular

  5. Indoor radon and thoron concentrations in the pyramides of Teotihuacan

    International Nuclear Information System (INIS)

    Radon and thoron concentrations measured in the prehispanic tunnel of the Sun Pyramid and in the archeological tunnel 1 in the Moon Pyramid are presented. Radon and thoron concentrations were measured using several electret passive environmental radon monitor (E-PERM) configurations and detection systems. Results were in good agreement with no significant difference (P E) calculated for the highest concentration was much lower than the action level (3-10 mSv x y-1). A quality assurance program was improved. (author)

  6. Geometry and perspective in the landscape of the Saqqara pyramids

    CERN Document Server

    Magli, Giulio

    2009-01-01

    A series of peculiar, visual alignments between the pyramids of the pharaohs of the 4, 5 and 6 Egyptian dynasties exists. These alignments governed from the very beginning the planning of the funerary monuments of successive kings and, in some cases, led to establish building sites in quite inconvenient locations from the technical viewpoint. Explaining the topography of these monuments means therefore also investigating on their symbolic motivations: religion, power, dynastic lineage and social context, as well as getting insights on the skills of the ancient architects in astronomy and geometry. In the present paper we focus on the relationships between the Old Kingdom pyramids at Saqqara.

  7. Binary TLBO algorithm assisted for designing plasmonic nano bi-pyramids-based absorption coefficient

    Science.gov (United States)

    Akhlaghi, Majid; Emami, Farzin; Nozhat, Najmeh

    2014-07-01

    A new efficient binary optimization method based on Teaching-Learning-Based Optimization (TLBO) algorithm is proposed to design an array of plasmonic nano bi-pyramids in order to achieve maximum absorption coefficient spectrum. In binary TLBO, a group of learners consisting of a matrix with binary entries controls the presence ('1') or the absence ('0') of nanoparticles in the array. Simulation results show that absorption coefficient strongly depends on the localized position of plasmonic nanoparticles. Non-periodic structures have more appropriate response in term of absorption coefficient. This approach is useful in optical applications such as solar cells and plasmonic nano antenna.

  8. Damage to the pyramidal tracts is necessary and sufficient for the production of the pyramidal syndrome in man.

    Science.gov (United States)

    de Oliveira-Souza, Ricardo

    2015-07-01

    The causal role played by damage to the pyramidal tracts in the production of spastic hemiplegia in man has been hotly debated over the past hundred years. Two broad streams of thought have emerged from this dispute. The first, which is grounded on the clinicopathological schools of Jean-Martin Charcot (1825-1893) and Paul Flechsig (1847-1929), claimed that the four cardinal signs of hemiplegia, namely (i) paralysis, (ii) spasticity, (iii) hyperactive phasic muscle reflexes ("tendon jerks") and (iv) the sign of Babinski, are caused by injury or dysfunction of the pyramidal tracts. The second school, championed by John Farquhar Fulton (1899-1960) and Derek Denny-Brown (1901-1981), reflects the increasing influence of experimental neurology on clinicopathological concepts after World War II. According to this school, most elements of the pyramidal syndrome are caused by the added release or injury of extrapyramidal structures at different levels of the forebrain and brainstem. Most symptoms of spastic hemiplegia were thus interpreted as signs of extrapyramidal (e.g., reticulospinal) release or damage. However, consensus on which symptoms of spastic hemiplegia were due to pyramidal or extrapyramidal changes was never reached. To add to this uncertainty, a number of clinicopathological cases that supported the old view were sporadically published over the same period. The purpose of the present essay is to provide clinicoanatomic perspective to the neurological literature in support of the hypothesis that damage to the pyramidal tracts is a necessary and sufficient condition for the production of the complete pyramidal syndrome in man. PMID:25959865

  9. 76 FR 15358 - Culturally Significant Objects Imported for Exhibition Determinations: “Before the Pyramids: The...

    Science.gov (United States)

    2011-03-21

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF STATE Culturally Significant Objects Imported for Exhibition Determinations: ``Before the Pyramids: The Origins of... ``Before the Pyramids: The Origins of Egyptian Civilization'' imported from abroad for temporary...

  10. Performance of resistance gene pyramids to races of rice bacterial blight in Zhejiang Province

    Institute of Scientific and Technical Information of China (English)

    ZHENGKangle; ZHUANGJieyun; WANGHanrong

    1998-01-01

    The effect of gene pyramiding on resistance to bacterial blight (BB) in rice was evahlated among the IR24-based near isogenic lines conraining single resistance gene and gene pyramids containing two, three or lour resistancegenes (see table).

  11. Amyloid β-protein differentially affects NMDA receptor- and GABAA receptor-mediated currents in rat hippocampal CA1 neurons

    Institute of Scientific and Technical Information of China (English)

    Junfang Zhang; Lei Hou; Xiuping Gao; Fen Guo; Wei Jing; Jinshun Qi; Jiantian Qiao

    2009-01-01

    Although the aggregated amyloid β-protein (Aβ) in senile plaques is one of the key neuropathological features of Alzheimer's disease (AD), soluble forms of Aβ also interfere with synaptic plasticity at the early stage of AD. The suppressive action of acute application of Aβ on hippocampal long-term potentiation (LTP) has been reported widely, whereas the mechanism underlying the effects of Aβ is still mostly unknown. The present study, using the whole-cell patch clamp technique, investigated the effects of Aβ fragments (Aβ25-35 and Aβ31-35) on the LTP induction-related postsynaptic ligand-gated channel currents in isolated hippocampal CA1 neurons. The results showed a rapid but opposite action of both peptides on excitatory and inhibitory receptor currents. Glutamate application-induced currents were suppressed by A β25-35 in a dose-dependent manner, and further N-methyl-I>aspartate (NMDA) receptor-mediated currents were selec-tively inhibited. In contrast, pretreatment with Aβ fragments potentiated γ-aminobutyric acid (GABA)-induced whole-cell currents. As a control, Aβ35-31 the reversed sequence of Aβ35-31 showed no effect on the currents induced by glutamate, NMDA or GABA. These results may partly explain the impaired effects of Aβ on hippocampal LTP, and suggest that the functional down-regulation of N M DA receptors and up-regulation of GABAA receptors may play an important role in remodeling the hippocampal synaptic plasticity in early AD.

  12. A first step toward combinatorial pyramids in nD spaces

    OpenAIRE

    Fourey, Sébastien; Brun, Luc

    2009-01-01

    Combinatorial maps define a general framework which allows to encode any subdivision of an nD orientable quasi-manifold with or without boundaries. Combinatorial pyramids are defined as stacks of successively reduced combinatorial maps. Such pyramids provide a rich framework which allows to encode fine properties of the objects (either shapes or partitions). Combinatorial pyramids have first been defined in 2D. This first work has latter been extended to pyramids of nD generalized combinatori...

  13. A first step toward combinatorial pyramids in n-D spaces

    OpenAIRE

    Fourey, Sébastien; Brun, Luc

    2009-01-01

    Combinatorial maps define a general framework which allows to encode any subdivision of an n-D orientable quasi-manifold with or without boundaries. Combinatorial pyramids are defined as stacks of successively reduced combinatorial maps. Such pyramids provide a rich framework which allows to encode fine properties of the objects (either shapes or partitions). Combinatorial pyramids have first been defined in 2D. This first work has later been extended to pyramids of n-D generalized combinator...

  14. Connecting walks and connecting dart sequences for n-D combinatorial pyramids

    OpenAIRE

    Fourey, Sébastien; Brun, Luc

    2009-01-01

    Combinatorial maps define a general framework which allows to encode any subdivision of an n-D orientable quasi-manifold with or without boundaries. Combinatorial pyramids are defined as stacks of successively reduced combinatorial maps. Such pyramids provide a rich framework which allows to encode fine properties of objects (either shapes or partitions). Combinatorial pyramids have first been defined in 2D. This first work has later been extended to pyramids of n-D generalized combinatorial ...

  15. 不同胰岛素治疗方案对糖尿病家兔大脑顶叶锥体细胞的影响%The effect of different insulin regimens on the pyramidal cells in the parietal lobe of diabetic rabbits brain

    Institute of Scientific and Technical Information of China (English)

    李妮; 钟玫; 陈晖; 莫祥兰; 周微雅; 陈翠玲; 黄莹

    2009-01-01

    Objective To investigate the optimal insulin regimens according to the pyramidal cells'change in the parietal lobe of brain on rabbit diabetes mellitus model. Methods Forty male rabbit were random divided into 5 group, including control group (group N) , model group (group D), group received multiple subcutaneous injection of insulin (group A) , group received isophane protamine biosyn-thetic human injection (pre-mixed 50R) (group B) , group received isophane protamine biosynthetic human injection (pre-mixed 30R) (group C). Homemade rabbit diabetes mellitus models induced by alloxan were divided into 4 groups. After 30 day, therapy group treatedwith insulin inject were put to death. Other group animal were sacrificed at the same time. The insulin dose and period at the targeted blood glucose level among 3 insulin groups, blood glucose, brain weight, the rate of apoptosis of the pyramidal cells and pathohistology change in the parietal lobe of the brain between untreated group and control groups were compared. Results Insulin dose needed by group B is less than group A and C. The largest amount of insulin was used in group C to get to the targeted blood glucose levels. There was significant difference among 3 groups ( P B > C. Conclusions Subcutaneous injection of pre-mixed 30R may be the optimal insulin treatment protocol. This regimen supplies more basal insulin and less bolus insulin. The blood glucose drops steadily, and the nerval tissue can be protected. Intensive insulin therapy by multiple subcutaneous injection (triple daily injections with short-acting insulin and once daily injection of intermediate-acting insulin or long-acting insulin) was not preferably recommended.%目的 以大脑顶叶锥体细胞的变化为判断标准,探讨家兔糖尿病模型胰岛素(Ins)用药治疗的适宜方案.方法 40只雄性家兔随机分成5组[对照组(N组)、模型组(D组)、多次Ins治疗组(A组)、50R预混Ins治疗组(B组)、30R

  16. Building trust at the Base of the Pyramid

    NARCIS (Netherlands)

    Grootveld, P.; Vermeulen, P.A.M.

    2014-01-01

    More and more companies are serving the poorest communities of our world, the so-called Base of the Pyramid (BoP). Wal-Mart, for example, moved into the Mexican retail-banking sector, claiming not only to “sell more stuff” but also to compete against the entrenched domestic businesses that are not f

  17. Was the Great Pyramid Built with Simple Machines?

    Science.gov (United States)

    Kraft, Susan; Poynor, Leslie

    2004-01-01

    Recently one of the authors challenged her third-grade students to use their imagination and travel with her to Egypt. As they were exploring the Great Pyramid, she encouraged the students to speculate how ancient people could have built such a massive structure without the sophisticated machinery they have at our disposal today. This article…

  18. Using the Pyramid Approach to Teaching Marketing Research.

    Science.gov (United States)

    Peltier, James W.; Westfall, John; Ainscough, Thomas L.

    2001-01-01

    Underscores the need for teaching marketing research skills at the secondary level and shows how marketing research fits into marketing education. Provides an example of how to use the pyramid approach to research, which involves review of secondary sources, key informant interviews, focus groups, and quantitative research. (Author/JOW)

  19. Radon measurements in the interior of the great pyramid

    International Nuclear Information System (INIS)

    Radon concentration measurements were made in the interior of the great pyramid of ''Cheops'' at Giza. Measurements were carried out using CR-39 as a solid state nuclear track detector. The CR-39 sheets were placed inside the Queen's and King's chambers and along the ascending corridor leading to them. An evaluation of the radon concentration is presented and discussed. (author)

  20. Ligand for neurotransmission SPECT in extra-pyramidal diseases

    International Nuclear Information System (INIS)

    It is now possible to study by scintigraphy some parameters of dopaminergic neurotransmission with iodinated ligands. Some clinical studies have shown the interest of this kind of exploration for the early diagnosis, the differential diagnosis and the follow-up of evolution and treatment of the different extra pyramidal pathologies. However, advances are still expected in several fields (tracers, cameras resolutions). (N.C.)

  1. The Sphinx and the Pyramids at Giza. Educational Packet.

    Science.gov (United States)

    Gagliano, Sara; Rapport, Wendy

    This packet of materials was created to accompany the exhibit "The Sphinx and the Pyramids: 100 Years of American Archaeology at Giza" at the Semitic Museum of Harvard University. The lessons and teacher's guide focus on the following: (1) "The Mystery of the Secret Tomb" where students take on the role of an archaeologist by attempting to solve a…

  2. Organizing innovation in base-of-the-pyramid projects

    NARCIS (Netherlands)

    Boer, J. de; Steen, M.G.D.; Posthumus, A.L.

    2013-01-01

    Base-of-the-Pyramid (BoP) inclusive innovation projects aim to design, produce and market products and services for large and relatively poor market segments in developing countries, for example for people who have less than several dollars to spend per day. BoP projects have ‘normal’ goals, deliver

  3. The pyramid model as a structured way of quality management

    Directory of Open Access Journals (Sweden)

    van der Tuuk Adriani Willem

    2008-01-01

    Full Text Available Three quality systems that can be used in blood establishments are briefly explained. The Pyramid model is described as a tool to manage the quality systems. Finally, some experiences in other countries are given to prove the validity of the system.

  4. Coxeter Decompositions of Bounded Hyperbolic Pyramids and Triangular Prisms

    OpenAIRE

    Felikson, A.

    2002-01-01

    Coxeter decompositions of hyperbolic simplices where studied in math.MG/0212010 and math.MG/0210067. In this paper we use the methods of these works to classify Coxeter decompositions of bounded convex pyramids and triangular prisms in the hyperbolic space H^3.

  5. Increasing Accurate Preference Assessment Implementation through Pyramidal Training

    Science.gov (United States)

    Pence, Sacha T.; St. Peter, Claire C.; Tetreault, Allison S.

    2012-01-01

    Preference assessments directly evaluate items that may serve as reinforcers, and their implementation is an important skill for individuals who work with children. This study examined the effectiveness of pyramidal training on teachers' implementation of preference assessments. During Experiment 1, 3 special education teachers taught 6 trainees…

  6. [Diagnostic significance of pathologic synkinesis for detection of pyramidal pathology].

    Science.gov (United States)

    Baliasnyĭ, M M

    1991-01-01

    Five types of pathological synkinesis (++blepharo-ocular, ++blepharo-facial, ++bucco-manual, ++digito-digital on the hands, ++pedo-digital) are described. They are of definite importance for revealing pyramidal pathology including its early stages as well as for objective evaluation and observation of the time-course of changes in the illness. PMID:1654715

  7. 艾灸预处理对阿尔茨海默病模型大鼠海马CA1区NGF和BDNF表达的影响%Effect of Moxibustion Pretreatment on Expression of NGF and BDNF in Hippocampus CA1 of Alzheimer Disease Model Rats

    Institute of Scientific and Technical Information of China (English)

    王晓兰; 孙国杰; 杜艳军; 李婧; 刘静; 刘若兰; 叶飞

    2011-01-01

    Objective: To evaluate the effects of moxibustion pretreatment at Baihui (GV20) and Shenshu (BL23) on the expression of NGF and BDNF in hippocampus CA1 of the Alzheimer disease (AD) model rats. Methods: Forty male adult SD rats were randomly and equally allocated into normal> sham operation, model and moxibustion pretreatment groups. After 40 times of moxibustion pretreatment at Baihui and Shenshu, bilateral hippocampi of moxibustion pretreatment and model rats were one-off injected with condensed AfJl-42 to establish the rat AD models. Morris' water maze test was used to e-valuate the learning and memory ability of rats. The expression of NGF and BDNF in the CA1 region of the hippocampus was detected by using immunohistochemical techniques. Results: As compared with normal and sham operation groups, learning and memory ability and the number of NGF and BDNF positive cells in hippocamal CA1 region of AD rats were obviously reduced in the Moxibustion pretreatment and model groups, and those in the Moxibustion pretreatment group were significantly increased as compared with the model group. Conclusion: Moxibustion pretreatment at the Baihui and Shenshu points can improve learning and memory ability of AD rats, which might be related with increased NGF and BDNF expression in the hippocampal CA1 region.%研究艾灸预处理百会和肾俞两穴对阿尔茨海默病(AD)模型大鼠脑组织海马CA1区中神经生长因子( NGF)和脑源性神经营养因子(BDNF)蛋白表达的影响及作用机制.方法:SD雄性成年大鼠40只,随机分为正常组、假手术组、模型组和预艾灸组各10只.预艾灸组采用艾灸百会及肾俞穴40次后,于模型组同时采用双侧海马一次性注射凝聚态Aβ1-42制备AD大鼠模型.以Morris水迷宫试验评价4组大鼠学习记忆能力;免疫组化法观察海马CA1区NGF和BDNF的阳性细胞计数.结果:与正常组和假手术组比较,预艾灸组和模型组学习记忆能力及海马CA1区NGF

  8. Nanopore formation on Au coated pyramid under electron beam irradiations (plasmonic nanopore on pyramid

    Directory of Open Access Journals (Sweden)

    Seong Soo Choi

    2016-03-01

    Full Text Available There have been tremendous interests about the single molecule analysis using a sold-state nanopore. The solid-state nanopore can be fabricated either by drilling technique, or diffusion technique by using electron beam irradiations. The solid-state SiN nanopore device with electrical detection technique recently fabricated, however, the solid-state Au nanopore with optical detection technique can be better utilized as the next generation single molecule sensor. In this report, the nanometer size openings with its size less than 10 nm on the diffused membrane on the 200 nm Au pyramid were fabricated by using field emission scanning electron microscopy (FESEM electron beam irradiations, transmission electron microscopy (TEM, etc. After the sample was being kept under a room environment for several months, several Au (111 clusters with ~6 nm diameter formed via Ostwald ripening are observed using a high resolution TEM imaging. The nanopore with Au nanoclusters on the diffused membrane can be utilized as an optical nanopore device.

  9. An algorithm for benchmarking an SIMD pyramid with the Abingdon Cross

    OpenAIRE

    Teeuw, W.B.; Duin, R. P. W.

    1990-01-01

    Benchmarking an SIMD pyramid with the Abingdon Cross is discussed. Measured results for a simulated pyramid architecture on a CLIP4 processor array are presented, as well as estimates for a hypothetical hardware pyramid built with CLIP4 like processing elements.

  10. FBXO7 mutations cause autosomal recessive, early-onset parkinsonian-pyramidal syndrome.

    NARCIS (Netherlands)

    Fonzo, A. Di; Dekker, M.C.J.; Montagna, P.; Baruzzi, A.; Yonova, E.H.; Correia Guedes, L.; Szczerbinska, A.; Zhao, T.; Dubbel-Hulsman, L.O.; Wouters, C.H.; Graaff, E. de; Oyen, W.J.G.; Simons, E.J.; Breedveld, G.J.; Oostra, B.A.; Horstink, M.W.I.M.; Bonifati, V.

    2009-01-01

    BACKGROUND: The combination of early-onset, progressive parkinsonism with pyramidal tract signs has been known as pallido-pyramidal or parkinsonian-pyramidal syndrome since the first description by Davison in 1954. Very recently, a locus was mapped in a single family with an overlapping phenotype, a

  11. Growth of Nucleation Sites on Pd-doped Bi_2Sr_2Ca1 Cu_2O_8+δ

    Science.gov (United States)

    Kouzoudis, D.; Finnemore, D. K.; Xu, Ming; Balachandran

    1996-03-01

    Enviromental Scanning Electron Microscope has shown evidence that during the growth of Bi_2Sr_2Ca_2Cu_3O_10+δ from mixed powders of Pb-doped Bi_2Sr_2Ca_1Cu_2O_8+δ and other oxides, a dense array of hillocks or mesas grow at the interface between an Ag overlay and Pb doped Bi_2Sr_2Ca_1Cu_2O_8+δ grains. These hillocks develop a texture that looks like ''chicken pox'' during the ramp up to the reaction temperature starting at about 700^circ C and they are about 500 to 1000 nm across and are spaced at about 500 to 1000 nm. If there is no Ag, this texture does not develop. Preliminary measurments indicate that the hillocks are re-crystallization of (Bi,Pb)_2Sr_2Ca_1Cu_2O_8+δ and are definetely not a Pb rich phase

  12. Neogene Palynomorphs from the 2-CA-1-RS Well, Pelotas Basin, Brazil: Biostratigraphic and Paleoecological Significance

    Directory of Open Access Journals (Sweden)

    Wagner Guimarães da Silva

    2011-04-01

    Full Text Available There is information available on calcareous microfossils found in the pre-Quaternary section of the Pelotas Basin.However, there is relatively sparse palynological data, since palynological studies only started to be systematicallyconducted in the last years. This paper presents palynological results regarding 20 samples collected between depths of262-145 m in the 2-CA-1-RS well, which is located in the onshore portion of this basin, in the Rio Grande do Sul state. Fivesamples showed rich and diverse associations of palynomorphs and fifteen samples showed a predominance of amorphousorganic matter or phytoclasts. Species of spores, pollen grains, dinoflagellate cysts, as well as microforaminiferal linigs,scolecodonts, acritarchs, Chlorococcales algae (Botryococcus and fungal spores were also identified in this study.Quantitative analysis on the distribution of particulate organic matter along the section allowed the identification oftwo palynological assemblages. The results indicate marine paleoenvironments, varying from the bottom to the top, forthe studied section. Assemblage 1 (262 – 248 m is interpreted as distal marine environment in open ocean, whereasAssemblage 2 (190 – 160 m is associated with proximal marine environments. The stratigraphic range of certain speciesof dinoflagellate cysts indicates ages ranging from the Miocene to the Quaternary.

  13. Synaptic plasticity in area CA1 of rat hippocampal slices following intraventricular application of albumin.

    Science.gov (United States)

    Salar, Seda; Lapilover, Ezequiel; Müller, Julia; Hollnagel, Jan-Oliver; Lippmann, Kristina; Friedman, Alon; Heinemann, Uwe

    2016-07-01

    Epileptogenesis following insults to the brain may be triggered by a dysfunctional blood-brain barrier (BBB) associated with albumin extravasation and activation of astrocytes. Using ex vivo recordings from the BBB-disrupted hippocampus after neocortical photothrombotic stroke, we previously demonstrated abnormal activity-dependent accumulation of extracellular potassium with facilitated generation of seizure like events and spreading depolarizations. Similar changes could be observed after intracerebroventricular (icv) application of albumin. We hypothesized that alterations in extracellular potassium and glutamate homeostasis might lead to alterations in synaptic interactions. We therefore assessed the effects of icv albumin on homo- and heterosynaptic plasticity in hippocampal CA1, 24h after a single injection or 7days after continuous infusion of icv albumin. We demonstrate alterations in both homo- and heterosynaptic plasticity compared to control conditions in ex vivo slice studies. Albumin-treated tissue reveals (1) reduced long-term depression following low-frequency stimulation; (2) increased long-term potentiation of population spikes in response to 20Hz stimulation; (3) potentiated responses to Schaffer collateral stimulation following high-frequency stimulation of the direct cortical input and low-frequency stimulation of alveus and finally, (4) TGFβ receptor II (TGFβR-II) involvement in albumin-induced homosynaptic plasticity changes. We conclude that albumin-induced network hyperexcitability is associated with abnormal homo- and heterosynaptic plasticity that could partly be reversed by interference with TGFβR-II-mediated signaling and therefore it might be an important factor in the process of epileptogenesis. PMID:26972679

  14. Neurofilament-labeled pyramidal neurons and astrocytes are deficient in DNA methylation marks in Alzheimer's disease.

    Science.gov (United States)

    Phipps, Andrew J; Vickers, James C; Taberlay, Phillippa C; Woodhouse, Adele

    2016-09-01

    There is increasing evidence that epigenetic alterations may play a role in Alzheimer's disease (AD); yet, there is little information regarding epigenetic modifications in specific cell types. We assessed DNA methylation (5-methylcytosine [5mC]) and hydroxymethylation (5-hydroxymethylcytosine [5hmC]) marks specifically in neuronal and glial cell types in the inferior temporal gyrus of human AD cases and age-matched controls. Interestingly, neurofilament (NF)-labeled pyramidal neurons that are vulnerable to AD pathology are deficient in extranuclear 5mC in AD cases compared with controls. We also found that fewer astrocytes exhibited nuclear 5mC and 5hmC marks in AD cases compared with controls. However, there were no alterations in 5mC and 5hmC in disease-resistant calretinin interneurons or microglia in AD, and there was no alteration in the density of 5mC- or 5hmC-labeled nuclei in near-plaque versus plaque-free regions in late-AD cases. 5mC and 5hmC were present in a high proportion of neurofibrillary tangles, suggesting no loss of DNA methylation marks in tangle bearing neurons. We provide evidence that epigenetic dysregulation may be occurring in astrocytes and NF-positive pyramidal neurons in AD. PMID:27459923

  15. Experimental assessment of the pyramidal energy on water.

    Directory of Open Access Journals (Sweden)

    Pedro Díaz Rebollido

    2006-04-01

    Full Text Available Background and objectives: The debate around the so called ¨pyramidal energy¨ among those that accept their multiple uses and those that reject them has been present both in the scientific community and the population. A recent research has suggested changes in the conductivity and the pH of the water, exposed to the pyramidal effect. The need to asses such a claim is the reason for the present study. Method: The study was developed in the laboratory of Physiology of the Faculty of Medical Sciences of Cienfuegos. We worked with 30 test tube numbered consecutively, stuffed with 500 ml of water. It was measured the electric conductivity and the pH of the wa-ter in each one of them. Later on, half of them, chosen at random, were placed during four hours under a pyramid, and the remaining ones were located outside of the pyramid. The electric conductivity and the pH were determined by means of the potenciometric method The pyramid employed was built with solid bars of aluminum, of skeletal structure; their dimensions were those established by specialists. It was placed so that two sides of its base were parallel to the North-South axis magnetic of the Earth. The measures were carried out in a blind way by one of the ours under the supervision of the other two co authors. Confidence intervals of the mean differences were computed under both experimental conditions and for the two considered variables. Complementarily, the stockings were compared by means of the Student t test. Results and Conclusions: The average (DS of the conductivity in the exposed test tubes to the pyramid before the exposition was 3,20 (0,07 and after 3,20 (0,05 (p=0,622; in the non exposed test tubes it was 3,18 (0,07 and 3,17 (0.06, (p=0.928. On the other hand, the average (DS values of the pH in the test tubes exposed to the pyramid before the exposition was 8,08 (0,78 and after 8.42 (0.13 (p=0.605, and in the non exposed test tubes 8,32 (0,89 and 8,44 (0,08, (p=0,127. The

  16. NR2A at CA1 Synapses Is Obligatory for the Susceptibility of Hippocampal Plasticity to Sleep Loss

    OpenAIRE

    Longordo, Fabio; Kopp, Caroline; Mishina, Masayoshi; Luján, Rafael; Lüthi, Anita

    2009-01-01

    A loss in the necessary amount of sleep alters expression of genes and proteins implicated in brain plasticity, but key proteins that render neuronal circuits sensitive to sleep disturbance are unknown. We show that mild (4–6 h) sleep deprivation (SD) selectively augmented the number of NR2A subunits of NMDA receptors on postsynaptic densities of adult mouse CA1 synapses. The greater synaptic NR2A content facilitated induction of CA3-CA1 long-term depression in the theta frequency stimulation...

  17. Inhomogeneous ferrimagnetic-like behavior in Gd2/3Ca1/3MnO3 single crystals

    OpenAIRE

    Haberkorn, N.; Larrégola, S.; Franco, D.; Nieva, G.

    2008-01-01

    We present a study of the magnetic properties of Gd2/3Ca1/3MnO3 single crystals at low temperatures. We show that this material behave as an inhomogeneous ferrimagnet. In addition to small saturation magnetization at 5 K, we have found history dependent effects in the magnetization and the presence of exchange bias. These features are compatible with microscopic phase separation in the clean Gd2/3Ca1/3MnO3 system studied.

  18. Altering sphingolipid composition with aging induces contractile dysfunction of gastric smooth muscle via K(Ca) 1.1 upregulation.

    Science.gov (United States)

    Choi, Shinkyu; Kim, Ji Aee; Kim, Tae Hun; Li, Hai-Yan; Shin, Kyong-Oh; Lee, Yong-Moon; Oh, Seikwan; Pewzner-Jung, Yael; Futerman, Anthony H; Suh, Suk Hyo

    2015-12-01

    K(Ca) 1.1 regulates smooth muscle contractility by modulating membrane potential, and age-associated changes in K(Ca) 1.1 expression may contribute to the development of motility disorders of the gastrointestinal tract. Sphingolipids (SLs) are important structural components of cellular membranes whose altered composition may affect K(Ca) 1.1 expression. Thus, in this study, we examined whether altered SL composition due to aging may affect the contractility of gastric smooth muscle (GSM). We studied changes in ceramide synthases (CerS) and SL levels in the GSM of mice of varying ages and compared them with those in young CerS2-null mice. The levels of C16- and C18-ceramides, sphinganine, sphingosine, and sphingosine 1-phosphate were increased, and levels of C22, C24:1 and C24 ceramides were decreased in the GSM of both aged wild-type and young CerS2-null mice. The altered SL composition upregulated K(Ca) 1.1 and increased K(Ca) 1.1 currents, while no change was observed in K(Ca) 1.1 channel activity. The upregulation of KC a 1.1 impaired intracellular Ca²⁺mobilization and decreased phosphorylated myosin light chain levels, causing GSM contractile dysfunction. Additionally, phosphoinositide 3-kinase, protein kinase Cζ , c-Jun N-terminal kinases, and nuclear factor kappa-B were found to be involved in K(Ca) 1.1 upregulation. Our findings suggest that age-associated changes in SL composition or CerS2 ablation upregulate K(Ca) 1.1 via the phosphoinositide 3-kinase/protein kinase Cζ /c-Jun N-terminal kinases/nuclear factor kappa-B-mediated pathway and impair Ca²⁺ mobilization, which thereby induces the contractile dysfunction of GSM. CerS2-null mice exhibited similar effects to aged wild-type mice; therefore, CerS2-null mouse models may be utilized for investigating the pathogenesis of aging-associated motility disorders. PMID:26288989

  19. A study on radiation energy of Pyramidal shape 1- Effect of housing within a Pyramid model on cancer growth and some blood parameters of mice

    International Nuclear Information System (INIS)

    A study of solid tumor growth retardation by impaling the pyramid energy radiation in a pyramidal model shape was carried out. The great Pyramid of Egypt has evoked a keen interest since 1920, both for its architectural, marvel and mystical significance. Its strange thing (via shaping of razers, longer shelf life of vegetables, alerted states of consciousnesses, sleeping in hum and, wound healing). Power energy radiations are said to occur within a pyramid constructed in the exact geometric properties of Giza pyramid. The effect of housing in two different pyramidal shapes on cancer growth and some blood physiological indices in mice infected with cancer were observed. The results obtained that housing in pyramid shape cage significantly reduced the development of cancer, significant increase in liver enzymes activity and α feto proteins, however, no effect was observed in levels of thyroid hormones concentration when compared with their matched value in ordinary 2 inverted pyramid cages. It could be concluded that the radiation energy of pyramidal shapes might improve certain biochemical and physiological indices leading to tumor growth retardation

  20. Microstructural characterization of the stabilized fluorite phases formed in the Ca1-yLayU2O6+x (0≤y≤0.8) system

    International Nuclear Information System (INIS)

    The thermal behaviour and stability of the fluorite structure in the Ca1-yLayU2O6+x (0≤y≤0.8) system during ageing have been studied by thermal analysis and X-ray powder diffraction. When the amount of La3+ incorporated into the Ca1-yLayU2O6+x structure is ≥0.6 the complete stabilization of the fluorite phase is achieved. This phase remains stable over the temperature range from room temperature-1400 C even after being submitted to long term give time. For lower amounts of La3+ a mixture of cubic fluorite and calcium lanthanum diuranate solid solution is obtained on annealing. The microstructural characterization carried out by electron diffraction and high resolution transmission electron microscopy reveals short range order for the high temperature quenched materials. Annealing of the oxides leads to the formation of ordered nanodomains embedded within the fluorite matrix, but no ordered single phase is isolated. A hexagonal cell of aH=3.8 and cH=18.8 A has been deduced for the domains. (orig.)

  1. Tissue Plasminogen Activator Expression Is Restricted to Subsets of Excitatory Pyramidal Glutamatergic Neurons.

    Science.gov (United States)

    Louessard, Morgane; Lacroix, Alexandre; Martineau, Magalie; Mondielli, Gregoire; Montagne, Axel; Lesept, Flavie; Lambolez, Bertrand; Cauli, Bruno; Mothet, Jean-Pierre; Vivien, Denis; Maubert, Eric

    2016-09-01

    Although the extracellular serine protease tissue plasminogen activator (tPA) is involved in pathophysiological processes such as learning and memory, anxiety, epilepsy, stroke, and Alzheimer's disease, information about its regional, cellular, and subcellular distribution in vivo is lacking. In the present study, we observed, in healthy mice and rats, the presence of tPA in endothelial cells, oligodendrocytes, mastocytes, and ependymocytes, but not in pericytes, microglial cells, and astrocytes. Moreover, blockage of the axo-dendritic transport unmasked tPA expression in neurons of cortical and hippocampal areas. Interestingly, combined electrophysiological recordings, single-cell reverse transcription polymerase chain reaction (RT-PCR), and immunohistological analyses revealed that the presence of tPA is restricted to subsets of excitatory pyramidal glutamatergic neurons. We further evidenced that tPA is stored in synaptobrevin-2-positive glutamatergic synaptic vesicles. Based on all these data, we propose the existence of tPA-ergic neurons in the mature brain. PMID:26377106

  2. Asiatic acid, a pentacyclic triterpene in Centella asiatica, attenuates glutamate-induced cognitive deficits in mice and apoptosis in SH-SY5Y cells

    Institute of Scientific and Technical Information of China (English)

    Min-fang XU; Yu-yun XIONG; Jian-kang LIU; Jin-jun QIAN; Li ZHU; Jing GAO

    2012-01-01

    To investigate whether asiatic acid (AA),a pentacyclic triterpene in Centella asiatica,exerted neuroprotective effects in vitro and in vivo,and to determine the underlying mechanisms.Methods:Human neuroblastoma SH-SY5Y cells were used for in vitro study.Cell viability was determined with the MTT assay.Hoechst 33342 staining and flow cytometry were used to examine the apoptosis.The mitochondrial membrane potential (MMP) and reactive oxygen species (ROS) were measured using fluorescent dye.PGC-1α and Sift1 levels were examined using Western blotting.Neonatal mice were given monosodium glutamate (2.5 mg/g) subcutaneously at the neck from postnatal day (PD) 7 to 13,and orally administered with AA on PD 14 daily for 30 d.The learning and memory of the mice were evaluated with the Morris water maze test.HE staining was used to analyze the pyramidal layer structure in the CA1 and CA3 regions.Results:Pretreatment of SH-SY5Y cells with AA (0.1-100 nmol/L) attenuated toxicity induced by 10 mmol/L glutamate in a concentration-dependent manner.AA 10 nmol/L significantly decreased apoptotic cell death and reduced reactive oxygen species (ROS),stabilized the mitochondrial membrane potential (MMP),and promoted the expression of PGC-1α and Sirt1.In the mice models,oral administration of AA (100 mg/kg) significantly attenuated cognitive deficits in the Morris water maze test,and restored lipid peroxidation and glutathione and the activity of SOD in the hippocampus and cortex to the control levels.AA (50 and 100 mg/kg) also attenuated neuronal damage of the pyramidal layer In the CA1 and CA3 regions.Conclusion:AA attenuates glutamate-induced cognitive deficits of mice and protects SH-SY5Y cells against glutamate-induced apoptosis in vitro.

  3. Using Pyramids Effects as a method of nuclear and radiation protection

    International Nuclear Information System (INIS)

    Results most of experiments fixed that When radioactive waste is placed inside the pyramids, there is a decrease in their level of radioactivity Based on result of these experiments we suggest - Using Pyramids Effects as a method of nuclear and radiation protection. Explanation of this method based on 3 factors. (2 of them - internal factors, 1 of them - external factor) Factor I. Based o the Theory of the Pyramids Effects we know, that Pyramid construction separate the normal geomagnetic field of the Earth to 2 parts, which have difference vise verse physical characteristics. Cause of the energetic barrier of side of Pyramid, internal space of the Pyramid isolate from the influence of the external normal geomagnetic field of Earth. Therefore, internal space of the Pyramid is fulfilling only by the attractive power of the Earth (pic.1)

  4. Repeating firing fields of CA1 neurons shift forward in response to increasing angular velocity.

    Science.gov (United States)

    Cowen, Stephen L; Nitz, Douglas A

    2014-01-01

    Self-motion information influences spatially-specific firing patterns exhibited by hippocampal neurons. Moreover, these firing patterns can repeat across similar subsegments of an environment, provided that there is similarity of path shape and head orientations across subsegments. The influence of self-motion variables on repeating fields remains to be determined. To investigate the role of path shape and angular rotation on hippocampal activity, we recorded the activity of CA1 neurons from rats trained to run on spiral-shaped tracks. During inbound traversals of circular-spiral tracks, angular velocity increases continuously. Under this condition, most neurons (74%) exhibited repeating fields across at least three adjacent loops. Of these neurons, 86% exhibited forward shifts in the angles of field centers relative to centers on preceding loops. Shifts were absent on squared-spiral tracks, minimal and less reliable on concentric-circle tracks, and absent on outward-bound runs on circular-spiral tracks. However, outward-bound runs on the circular-spiral track in the dark were associated with backward shifts. Together, the most parsimonious interpretation of the results is that continuous increases or decreases in angular velocity are particularly effective at shifting the center of mass of repeating fields, although it is also possible that a nonlinear integration of step counts contributes to the shift. Furthermore, the unexpected absence of field shifts during outward journeys in light (but not darkness) suggests visual cues around the goal location anchored the map of space to an allocentric reference frame. PMID:24381284

  5. Distributed GIS oriented generalized image pyramid and its practice

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Gaussian pyramid framework (GPF) and Laplacian pyramid framework (LPF) are the two main frameworks used for transmission and structure of spatial image and geometric data.LPF is the main approach for progressive transmission of spatial image data.This paper discusses the issues in structure,transmission and storage efficiency of spatial data in the current spatially distributed visualization system.Later in the paper a novel approach is introduced to structure and store spatial data based on the LPF.This new approach builds (spatial) index for transformed frequency data within different ranges based on splitting high-frequency and low-frequency data by biorthogonal transformation.This approach decreases the storage consumption and network data traffic for transmission while enables the progressive transmission of spatial image.

  6. Expression of Bacillus thuringiensis Cytolytic Toxin (Cyt2Ca1) in citrus roots to control Diaprepes abbreviatus larvae

    Science.gov (United States)

    Diaprepes abbreviatus (L.) is an important pest of citrus in the USA. Currently, no effective management strategies of Diaprepes abbreviatus exist in citriculture. To protect citrus against Diaprepes abbreviatus a transgenic citrus rootstock expressing Bacillus thuringiensis Cyt2Ca1, an insect toxin...

  7. New considerations on construction methods of the Ancient Egyptian pyramids

    OpenAIRE

    Müller-Römer, Frank

    2011-01-01

    Many authors have attempted to account for the construction methods of the Old Kingdom pyramids, offering a broad scope of hypotheses concerning construction processes, building phases, mechanical devices, and workforce. Still, none of these suggestions have proved quite conclusive. All previous explanations involving ramps start from the assumption that building blocks were conveyed upwards on sledges pulled by bulls or workmen. However, in this case, sufficiently long ramps with a lesser sl...

  8. A Deep Pyramid Deformable Part Model for Face Detection

    OpenAIRE

    Ranjan, Rajeev; Patel, Vishal M.; Chellappa, Rama

    2015-01-01

    We present a face detection algorithm based on Deformable Part Models and deep pyramidal features. The proposed method called DP2MFD is able to detect faces of various sizes and poses in unconstrained conditions. It reduces the gap in training and testing of DPM on deep features by adding a normalization layer to the deep convolutional neural network (CNN). Extensive experiments on four publicly available unconstrained face detection datasets show that our method is able to capture the meanin...

  9. A novel optical multilayer hydrophone with a triangular pyramid substrate

    Institute of Scientific and Technical Information of China (English)

    Suyong Wu; Xingwu Long; Kaiyong Yang; Yun Huang

    2011-01-01

    @@ A novel concept for an optical multilayer ultrasonic hydrophone with the sensing film deposited on a triangular pyramid glass substrate is proposed. Using the calculation model for the spectral coefficients' derivatives of a dielectric multilayer optical coating, the acousto-optic sensitivity characteristic of the hydrophone is analyzed with different measurement laser polarizations and incident angles. We present a reasonable method and adjusting strategy for the optimum working point selection of the ultrasound measurement. Analytic results show that the novel hydrophone possesses all the other merits of a plate glass substrate optical multilayer hydrophone but with improved detection sensitivity. A longer measurement time without distortion decreases the difficulty of high frequency signal circuits. Spatial split of the ultrasound signal caused by the substrate's triangular pyramid roof simplifies the spatial spot area correction,which contributes to the accurate calibration of the hydrophone's wideband frequency response.%A novel concept for an optical multilayer ultrasonic hydrophone with the sensing film deposited on a triangular pyramid glass substrate is proposed. Using the calculation model for the spectral coefficients'derivatives of a dielectric multilayer optical coating, the acousto-optic sensitivity characteristic of the hydrophone is analyzed with different measurement laser polarizations and incident angles. We present a reasonable method and adjusting strategy for the optimum working point selection of the ultrasound measurement. Analytic results show that the novel hydrophone possesses all the other merits of a plate glass substrate optical multilayer hydrophone but with improved detection sensitivity. A longer measurement time without distortion decreases the difficulty of high frequency signal circuits. Spatial split of the ultrasound signal caused by the substrate's triangular pyramid roof simplifies the spatial spot area correction

  10. Induced Retirement, Social Security, and the Pyramid Mirage

    OpenAIRE

    Casey B. Mulligan

    2000-01-01

    Does Social Security redistribute across cohorts? Or is it a program for purchasing the jobs' of the elderly? I formalize both models, showing how they have some predictions in common the most important of which is that generational accounts have the appearance of a pyramid scheme.' I also derive important differences between the two interpretations, and compare those differences with data on the design and incidence of Social Security programs around the world. Since implicit and explicit ta...

  11. Genetic Stereo Matching Using Complex Conjugate Wavelet Pyramids

    OpenAIRE

    L. Luo; Clewer, DR; Canagarajah, CN; Bull, DR

    2001-01-01

    A new genetic algorithm-based optimisation technique for stereo matching using complex conjugate wavelet pyramids is proposed. Reliable disparity fields are estimated in the wavelet domain with low computational cost. The new cost function is composed of the differences in wavelet coefficient values, plus vertical discontinuity and ordering constraints. Within homogenous regions, smoothness constraints on the disparity field are also employed. A genetic algorithm is used, where previously est...

  12. Geometry and perspective in the landscape of the Saqqara pyramids

    OpenAIRE

    Magli, Giulio

    2009-01-01

    A series of peculiar, visual alignments between the pyramids of the pharaohs of the 4, 5 and 6 Egyptian dynasties exists. These alignments governed from the very beginning the planning of the funerary monuments of successive kings and, in some cases, led to establish building sites in quite inconvenient locations from the technical viewpoint. Explaining the topography of these monuments means therefore also investigating on their symbolic motivations: religion, power, dynastic lineage and soc...

  13. Invariant representative cocycles of cohomology generators using irregular graph pyramids

    OpenAIRE

    González Díaz, Rocío; Ion, Adrián; Iglesias Ham, Mabel; Kropatsch, Walter G.

    2011-01-01

    Structural pattern recognition describes and classifies data based on the relationships of features and parts. Topological invariants, like the Euler number, characterize the structure of objects of any dimension. Cohomology can provide more refined algebraic invariants to a topological space than does homology. It assigns `quantities' to the chains used in homology to characterize holes of any dimension. Graph pyramids can be used to describe subdivisions of the same object at multiple level...

  14. Combinatorial pyramids and discrete geometry for energy-minimizing segmentation

    OpenAIRE

    Braure De Calignon, Martin; Brun, Luc; Lachaud, Jacques-Olivier

    2009-01-01

    This paper defines the basis of a new hierarchical framework for segmentation algorithms based on energy minimization schemes. This new framework is based on two formal tools. First, a combinatorial pyramid encode efficiently a hierarchy of partitions. Secondly, discrete geometric estimators measure precisely some important geometric parameters of the regions. These measures combined with photometrical and topological features of the partition allows to design energy terms based on discrete m...

  15. Image content authentication technique based on Laplacian Pyramid

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    This paper proposes a technique of image content authentication based on the Laplacian Pyramid to verify the authenticity of image content.First,the image is decomposed into Laplacian Pyramid before the transformation.Next,the smooth and detail properties of the original image are analyzed according to the Laplacian Pyramid,and the properties are classified and encoded to get the corresponding characteristic values.Then,the signature derived from the encrypted characteristic values is embedded in the original image as a watermark.After the reception,the characteristic values of the received image are compared with the watermark drawn out from the image.The algorithm automatically identifies whether the content is tampered by means of morphologic filtration.The information of tampered location is Presented at the same time.Experimental results show that the pro posed authentication algorithm can effectively detect the event and location when the original image content is tampered.Moreover,it can tolerate some distortions produced by compression,filtration and noise degradation.

  16. Amending Miller's Pyramid to Include Professional Identity Formation.

    Science.gov (United States)

    Cruess, Richard L; Cruess, Sylvia R; Steinert, Yvonne

    2016-02-01

    In 1990, George Miller published an article entitled "The Assessment of Clinical Skills/Competence/Performance" that had an immediate and lasting impact on medical education. In his classic article, he stated that no single method of assessment could encompass the intricacies and complexities of medical practice. To provide a structured approach to the assessment of medical competence, he proposed a pyramidal structure with four levels, each of which required specific methods of assessment. As is well known, the layers are "Knows," "Knows How," "Shows How," and "Does." Miller's pyramid has guided assessment since its introduction; it has also been used to assist in the assessment of professionalism.The recent emphasis on professional identity formation has raised questions about the appropriateness of "Does" as the highest level of aspiration. It is believed that a more reliable indicator of professional behavior is the incorporation of the values and attitudes of the professional into the identity of the aspiring physician. It is therefore proposed that a fifth level be added at the apex of the pyramid. This level, reflecting the presence of a professional identity, should be "Is," and methods of assessing progress toward a professional identity and the nature of the identity in formation should be guided by currently available methods. PMID:26332429

  17. The pyramid wavefront sensor for the high order testbench (HOT)

    Science.gov (United States)

    Pinna, E.; Puglisi, A. T.; Quiros-Pacheco, F.; Busoni, L.; Tozzi, A.; Esposito, S.; Aller-Carpentier, E.; Kasper, M.

    2008-07-01

    The High Order Testbench (HOT) is a joint experiment of ESO, Durham University and Arcetri Observatory to built and test in laboratory the performance of Shack-Hartmann and pyramid sensor in a high-order correction loop using a 32x32 actuators MEMS DM. This paper will describe the pyramid wavefront sensor unit developed in Arcetri and now installed in the HOT bench at ESO premises. In the first part of this paper we will describe the pyramid wavefront sensor opto-mechanics and its real-time computer realized with a commercial Linux-PC. In the second part we will show the sensor integration and alignment in the HOT bench and the experimental results obtained at ESO labs. Particular attention will be paid to the implementation of the modal control strategy, like modal basis definition, orthogonalization on the real pupil, and control of edge actuators. A stable closed loop controlling up to 667 modes has been achieved obtaining a Strehl ratio of 90 -- 93% in H band.

  18. Gonadal Steroids: Effects on Excitability of Hippocampal Pyramidal Cells

    Science.gov (United States)

    Teyler, Timothy J.; Vardaris, Richard M.; Lewis, Deborah; Rawitch, Allen B.

    1980-08-01

    Electrophysiological field potentials from hippocampal slices of rat brain show sex-linked differences in response to 1 × 10-10M concentrations of estradiol and testosterone added to the incubation medium. Slices from male rats show increased excitability to estradiol and not to testosterone. Slices from female rats are not affected by estradiol, but slices from female rats in diestrus show increased excitability in response to testosterone whereas slices from females in proestrus show decreased excitability.

  19. Different patterns of amygdala priming differentially affect dentate gyrus plasticity and corticosterone, but not CA1 plasticity.

    Directory of Open Access Journals (Sweden)

    Rose-Marie eVouimba

    2013-05-01

    Full Text Available Stress-induced activation of the amygdala is involved in the modulation of memory processes in the hippocampus. However, stress effects on amygdala and memory remain complex. The activation of the basolateral amygdala (BLA was found to modulate plasticity in other brain areas, including the hippocampus. We previously demonstrated a differential effect of BLA priming on LTP in the CA1 and the dentate gyrus (DG. While BLA priming suppressed long term potentiation (LTP in CA1, it was found to enhance it in the DG. However, since the amygdala itself is amenable to experience-induced plasticity it is thus conceivable that when activity within the amygdala is modified this will have impact on the way the amygdala modulates activity and plasticity in other brain areas. In the current study we examined the effects of different patterns of BLA activation on the modulation of LTP in the DG and CA1, as well as on serum corticosterone (CORT. In CA1, BLA priming impaired LTP induction as was reported before. In contrast, in the DG, varying BLA stimulation intensity and frequency resulted in differential effects on LTP, ranging from no effect to strong impairment or enhancement. Varying BLA stimulation patterns resulted in also differential alterations in Serum CORT, leading to higher CORT levels being positively correlated with LTP magnitude in DG but not in CA1.The results support the notion of a differential role for the DG in aspects of memory, and add to this view the possibility that DG-associated aspects of memory will be enhanced under more emotional or stressful conditions. It is interesting to think of BLA patterns of activation and the differential levels of circulating CORT as two arms of the emotional and stress response that attempt to synchronize brain activity to best meet the challenge. It is foreseeable to think of abnormal such synchronization under extreme conditions, which would lead to the development of maladaptive behavior.

  20. Electrical Properties of Ba3Ca1.18Nb1.82O9-  Proton-Conducting Electrolyte Prepared by a Combustion Method

    KAUST Repository

    Bi, Lei

    2013-10-07

    Ba3Ca1.18Nb1.82O9-δ (BCN18), regarded as a promising proton-conducting electrolyte material for solid oxide fuel cells, is usually synthesized by a solid-state reaction because of the limited choice of Nb precursors. This study presents a wet chemical route for preparing BCN18 powders that were then sintered into pellets. Electrochemical impedance spectroscopy studies indicated that BCN18 pellets show proton conductivity, since their total conductivity in wet air was significantly larger than that in dry air. However, a detailed analysis showed that only the BCN18 bulk behaves as a proton conductor, while its grain boundary conductivity did not increase in wet air.

  1. Technique Based on Image Pyramid and Bayes Rule for Noise Reduction in Unsupervised Change Detection

    Institute of Scientific and Technical Information of China (English)

    LI Zhi-qiang; HUO hong; FANG Tao; ZHU Ju-lian; GE Wei-li

    2009-01-01

    In this paper, a technique based on image pyramid and Bayes rule for reducing noise effects in unsupervised change detection is proposed. By using Gaussian pyramid to process two multitemporal images respectively, two image pyramids are constructed. The difference pyramid images are obtained by point-by-point subtraction between the same level images of the two image pyramids. By resizing all difference pyramid images to the size of the original multitemporal image and then making product operator among them, a map being similar to the difference image is obtained. The difference image is generated by point-by-point subtraction between the two multitemporal images directly. At last, the Bayes rule is used to distinguish the changed pixels. Both synthetic and real data sets are used to evaluate the performance of the proposed technique. Experimental results show that the map from the proposed technique is more robust to noise than the difference image.

  2. Study of gel grown mixed crystals of BaCa(1–)(IO3)4

    Indian Academy of Sciences (India)

    S L Garud; N K Mahajan; K B Saraf

    2009-04-01

    The growth of mixed crystals of BaCa1–(IO3)4 were carried out with simple gel method. The effect of various parameters such as pH of gel solution, gel concentration, gel setting time, concentration of reactants on the growth was studied. Crystals having different morphologies and habits were obtained. The grown crystals were characterized by XRD, FT–IR, EDAX, TGA, DTA and DSC.

  3. Ischemic preconditioning acts upstream of GluR2 down-regulation to afford neuroprotection in the hippocampal CA1

    OpenAIRE

    Tanaka, Hidenobu; Calderone, Agata; Jover, Teresa; Grooms, Sonja Y.; Yokota, Hidenori; Zukin, R. Suzanne; Bennett, Michael V. L.

    2002-01-01

    Animals subjected to sublethal transient global ischemia (ischemic preconditioning) exhibit neuroprotection against subsequent global ischemia-induced neuronal death in the hippocampal CA1 (ischemic tolerance). The molecular mechanisms underlying ischemic tolerance are unclear. Here we report that ischemic preconditioning induced a small, transient down-regulation of GluR2 mRNA expression and greatly attenuated subsequent ischemia-induced GluR2 mRNA and protein down-regulation and neuronal de...

  4. Pyramidal Neurons Switch From Integrators In Vitro to Resonators Under In Vivo-Like Conditions

    OpenAIRE

    Prescott, Steven A.; Ratté, Stéphanie; De Koninck, Yves; Sejnowski, Terrence J.

    2008-01-01

    During wakefulness, pyramidal neurons in the intact brain are bombarded by synaptic input that causes tonic depolarization, increased membrane conductance (i.e., shunting), and noisy fluctuations in membrane potential; by comparison, pyramidal neurons in acute slices typically experience little background input. Such differences in operating conditions can compromise extrapolation of in vitro data to explain neuronal operation in vivo. For instance, pyramidal neurons have been identified as i...

  5. Formation of the Pyramid Lake Paiute Tribal Council, 1934-1936

    OpenAIRE

    Rusco, Elmer R.

    1988-01-01

    The Pyramid Lake Paiute Tribe is today recognized by the federal government as a semi-sovereign society within the American polity. Its government, the Pyramid Lake Paiute Tribal Council, is acknowledged to be the governing body of the tribe and to have jurisdiction over the Pyramid Lake Reservation in northwestern Nevada, except where that jurisdiction has been eliminated or weakened by explicit action of the Congress of the United States (Cohen 1982). Before the 1930s, however, although the...

  6. Determinants of Firm Affiliation to Pyramid Structure: A Survey from Malaysian Public Listed Firms

    OpenAIRE

    Irfah Najihah Basir Malan; Norhana Salamudin; Noryati Ahmad

    2013-01-01

    This research seeks to examine the determinants of affiliation to pyramid structure of Malaysian public listed firms. A motivation of the research comes from the phenomenon of pyramid structure causing divergence of ultimate owners’ actual ownership and control leading to severe expropriation of minority shareholders’ interest. The method adapts Attig Model and employs Panel Generalised Least Square on 136 Malaysian pyramid firms over a twenty one-year period from 1990 to 2010. There are ten ...

  7. Higher-Order Finite Elements for Hybrid Meshes Using New Nodal Pyramidal Elements

    OpenAIRE

    Bergot, Morgane; Cohen, Gary; Duruflé, Marc

    2010-01-01

    We provide a comprehensive study of arbitrarily high-order finite elements defined on pyramids. We propose a new family of high-order nodal pyramidal finite element which can be used in hybrid meshes which include hexahedra, tetrahedra, wedges and pyramids. Finite elements matrices can be evaluated through approximate integration, and we show that the order of convergence of the method is conserved. Numerical results demonstrate the efficiency of hybrid meshes compared to pure tetrahedral mes...

  8. Removal and contraction operations to define combinatorial pyramids: application to the design of a spatial modeler

    OpenAIRE

    Damiand, Guillaume; Dexet, Martine; Lienhardt, Pascal; Andres, Eric

    2005-01-01

    Removal and contraction are basic operations for several methods conceived in order to handle irregular image pyramids, for multi-level image analysis for instance. We give the definitions of removal and contraction operations in the generalized maps framework. We propose a first experimentation of irregular pyramid as a basis for a discrete geometrical modeler that can handle both discrete and continuous representations of geometrical objects. This modeler is based on a pyramidal kernel with...

  9. Pyramidal and Chiral Groupings of Gold Nanocrystals Assembled Using DNA Scaffolds

    OpenAIRE

    Mastroianni, Alexander

    2009-01-01

    Nanostructures constructed from metal and semiconductor nanocrystals conjugated to, and organized by DNA are an emerging class of material with collective optical properties. We created discrete pyramids of DNA with gold nanocrystals at the tips. By taking small angle X-ray scattering (SAXS) measurments from solutions of these pyramids we confirmed that this pyramidal geometry creates structures which are more rigid in solution than linear DNA. We then took advantage of the tetrahedral sym...

  10. Fabrication of micro-mirrors with pyramidal shape using anisotropic etching of silicon

    CERN Document Server

    Moktadir, Z; Koukharenko, E; Kraft, M; Prakash, G V; Baumberg, J J; Trupke, M; Eriksson, S; Hinds, E A

    2004-01-01

    Gold micro-mirrors have been formed in silicon in an inverted pyramidal shape. The pyramidal structures are created in the (100) surface of a silicon wafer by anisotropic etching in potassium hydroxide. High quality micro-mirrors are then formed by sputtering gold onto the smooth silicon (111) faces of the pyramids. These mirrors show great promise as high quality optical devices suitable for integration into MOEMS systems.

  11. Nanoreplicated positive and inverted sub-micron polymer pyramids array for surface enhanced Raman spectroscopy (SERS)

    OpenAIRE

    Xu, Zhida; Liu, Logan

    2014-01-01

    We demonstrate gold coated polymer surface enhanced Raman scattering (SERS) substrates with a pair of complementary structures--positive and inverted pyramids array structures fabricated by multiple-step molding and replication process. The uniform SERS enhancement factors over the entire device surfaces were measured as 7.2 X 10^4 for positive pyramids substrate while 1.6 X 10^6 for inverted pyramids substrate with Rhodamine 6G as the target analyte. Based on the optical reflection measureme...

  12. On the problem of the stability of pyramidal structures on bombarded copper surfaces

    International Nuclear Information System (INIS)

    The morphological evolution of pyramids, developed on bombarded copper surfaces, as a function of consecutive doses of 12 keV Kr+ ions from 2.4 x 1016 up to 3 x 1019 ions/cm2, has been studied. In disagreement with many previous studies, apparently based on a limited choice of doses which were sometimes not in sequence, it was found that the pyramids disappeared at high enough doses. Pyramids are therefore not an equilibrium structure. (author)

  13. Pyramidal and Chiral Groupings of Gold Nanocrystals Assembled Using DNA Scaffolds

    OpenAIRE

    Mastroianni, Alexander; Claridge, Shelley; Alivisatos, A. Paul

    2009-01-01

    Nanostructures constructed from metal and semiconductor nanocrystals conjugated to, and organized by DNA are an emerging class of material with collective optical properties. We created discrete pyramids of DNA with gold nanocrystals at the tips. By taking small angle X-ray scattering (SAXS) measurments from solutions of these pyramids we confirmed that this pyramidal geometry creates structures which are more rigid in solution than linear DNA. We then took advantage of the tetrahedral symmet...

  14. Spatial memory decline after masticatory deprivation and aging is associated with altered laminar distribution of CA1 astrocytes

    Directory of Open Access Journals (Sweden)

    Frota de Almeida Marina

    2012-02-01

    Full Text Available Abstract Background Chewing imbalances are associated with neurodegeneration and are risk factors for senile dementia in humans and memory deficits in experimental animals. We investigated the impact of long-term reduced mastication on spatial memory in young, mature and aged female albino Swiss mice by stereological analysis of the laminar distribution of CA1 astrocytes. A soft diet (SD was used to reduce mastication in the experimental group, whereas the control group was fed a hard diet (HD. Assays were performed in 3-, 6- and 18-month-old SD and HD mice. Results Eating a SD variably affected the number of astrocytes in the CA1 hippocampal field, and SD mice performed worse on water maze memory tests than HD mice. Three-month-old mice in both groups could remember/find a hidden platform in the water maze. However, 6-month-old SD mice, but not HD mice, exhibited significant spatial memory dysfunction. Both SD and HD 18-month-old mice showed spatial memory decline. Older SD mice had astrocyte hyperplasia in the strata pyramidale and oriens compared to 6-month-old mice. Aging induced astrocyte hypoplasia at 18 months in the lacunosum-moleculare layer of HD mice. Conclusions Taken together, these results suggest that the impaired spatial learning and memory induced by masticatory deprivation and aging may be associated with altered astrocyte laminar distribution and number in the CA1 hippocampal field. The underlying molecular mechanisms are unknown and merit further investigation.

  15. Growth of nucleation sites on Pb-doped Bi2Sr2Ca1Cu2O8 + delta

    Science.gov (United States)

    Finnemore, D. K.; Xu, Ming; Kouzoudis, D.; Bloomer, T.; Kramer, M. J.; McKernan, Stuart; Balachandran, U.; Haldar, Pradeep

    1996-01-01

    In the growth of Bi2Sr2Ca2Cu3O10+δ from mixed powders of Pb-doped Bi2Sr2Ca1Cu2O8+δ and other oxides, it has been discovered that a dense array of hillocks or mesas grow at the interface between a Ag overlay and Pb-doped Bi2Sr2Ca1Cu2O8+δ grains during the ramp up to the reaction temperature. As viewed in an environmental scanning electron microscope, the Ag coated grains develop a texture that looks like ``chicken pox'' growing on the grains at about 700 °C. These hillocks are about 100 nm across and are spaced at about 500 to 1000 nm. If there is no Ag, this texture does not develop. Preliminary measurements indicate that the hillocks are a recrystallization of (Bi,Pb)2Sr2Ca1Cu2O8+δ, and are definitely not a Pb rich phase.

  16. Astronomical Orientation of Pyramid Tombs in North China

    Science.gov (United States)

    Rusell Tiede, Vance

    2010-01-01

    Two ancient Chinese texts, the Chou Bei Suan Ching and Chou Li (Western Han Dynasty, ca. 100 BC), record that the Imperial Astronomer (Feng Hsian Shin) made solar observations to determine the solstices and equinoxes, and for determining the cardinal directions with a circle and gnomon. By combining the techniques of astro-archaeology (G. S. Hawkins, 1968) with both overhead imagery and ground survey, the present study seeks to link historical Chinese descriptions of astronomical phenomena with contemporary architectural orientation. In the process, several unexpected astronomical orientation patterns emerged which apparently do not appear in the surviving historical record. For example, at the imperial Western Han capital of Ch'ang-an (N 34° latitude), the diagonals of cardinally oriented square pyramid mounds (ling) align to zenith (+34° declination) and nadir (-34° declination) star rise and set points on the skyline. This is in accord with the Chou (Zhou) Dynasty's name of Chung-Kuo, meaning Central Country or Middle Kingdom. That is, the imperial capital is centered both politico-geographically with respect to its vassal states of the Eastern Yi, Southern Man, Western Rong, and Northern Di, as well as astro-geomantically regarding the color-coded Five Sacred Directions East-South-West-North-Zenith/Nadir in the Cosmos. Our ground survey also confirmed pyramid orientation to the lunar standstills (+28°, +18° and +5° declination) that we reported from overhead imagery in 1980 (155th AAS Meeting, HAD 18.CE.12, Lunar and Solar Alignments of Ancient Chinese Pyramids). Grateful acknowledgment is given to the Chinese Academy of Sciences for the invitation to conduct an astro-archaeological survey of the Wei-ho valley, Shensi (Shaanxi) Province.

  17. Using cosmic muons to search for cavities in the Pyramid of the Sun, Teotihuacan: preliminary results

    International Nuclear Information System (INIS)

    Over the last two years the Pyramid of the Sun, at Teotihuacan, Mexico, has been searched for possible hidden chambers by means of muon attenuation measurements inside the monument’s volume. The experimental method is based on the use of a muon tracker placed in a chamber at the end of a tunnel, which runs below the base, and ends close to the symmetry axis of the pyramid. The accumulated experimental data, when compared to physics simulations using GEANT4, already show identifiable known features of the external shape of the pyramid. Experimental results of the relative density distribution inside the pyramid are presented and compared to the aforementioned Monte Carlo simulations

  18. Rezension zu: Emily Teeter (Hg.), Before the pyramids. The origins of Egyptian civilization

    OpenAIRE

    Köpp-Junk, Heidi

    2013-01-01

    Rezension zu: Emily Teeter (Hg.), Before the Pyramids. The Origins of Egyptian Civilization. The Oriental Institute of the University of Chicago, Oriental Institute Museum Publications 33 (Chicago 2011)

  19. Enumeration of pyramids of one-dimensional pieces of arbitrary fixed integer length

    OpenAIRE

    Durhuus, Bergfinnur; Eilers, Søren

    2009-01-01

    We consider pyramids made of one-dimensional pieces of fixed integer length a and which may have pairwise overlaps of integer length from 1 to a. We prove that the number of pyramids of size m, i.e. consisting of m pieces, equals (am-1,m-1) for each a >= 2. This generalises a well known result for a = 2. A bijective correspondence between so-called right (or left) pyramids and a-ary trees is pointed out, and it is shown that asymptotically the average width of pyramids is proportional to t...

  20. Combinatorial aspects of pyramids of one-dimensional pieces of fixed integer length

    OpenAIRE

    Durhuus, Bergfinnur; Eilers, Søren

    2010-01-01

    We consider pyramids made of one-dimensional pieces of fixed integer length a and which may have pairwise overlaps of integer length from 1 to a. We give a combinatorial proof that the number of pyramids of size m, i.e., consisting of m pieces, equals am-1\\choose m-1 for each a≥2. This generalises a well known result for a=2. A bijective correspondence between so-called right (or left) pyramids and a-ary trees is pointed out, and it is shown that asymptotically the average width of pyramids e...

  1. The production of regular pyramids on argon ion bombarded surfaces of copper crystals

    International Nuclear Information System (INIS)

    Argon ion bombardment of poly-crystalline copper is shown to produce pyramid covered surfaces on grains having orientation in particular high index direction. Single crystals cut in similar direction also show pyramid covered surfaces when bombarded with 40 keV argon ions. Evidence is presented to show that the dominant parameter contributing to pyramid production is crystallographic, rather than impurity-induced as proposed in earlier works. The pyramids are of such regular size, shape and spacing that light is selectively absorbed and for 40 keV argon ion bombardment, only light of red colour is reflected from an initially plane surface. (Auth.)

  2. Papillary thyroid microcarcinoma in a thyroid pyramidal lobe

    International Nuclear Information System (INIS)

    We report an extremely rare case of papillary thyroid microcarcinoma (PTMC) in the thyroid pyramidal lobe (TPL). A 48-year-old woman underwent ultrasound-guided fine-needle aspiration for a small thyroid nodule in the right lobe in local clinic, and it revealed a malignant cytology. On preoperative ultrasonography for tumor staging in our hospital, another small suspiciously malignant hypoechoic nodule was detected in the left TPL. Total thyroidectomy and central nodal dissection were performed. Histopathology confirmed PTMCs in the left TPL and both thyroid lobes. Ultrasonography for TPL should be required for complete evaluation of possible multifocality of thyroid malignancy.

  3. Dynamics of multi-tethered pyramidal satellite formation

    Science.gov (United States)

    Alary, D.; Andreev, K.; Boyko, P.; Ivanova, E.; Pritykin, D.; Sidorenko, V.; Tourneur, C.; Yarotsky, D.

    2015-12-01

    This paper is devoted to the dynamics of a multi-tethered pyramidal satellite formation rotating about its axis of symmetry in the nominal mode. Whereas the combination of rotation and gravity-gradient forces is insufficient to maintain the mutual positions of satellites, they are assumed to be equipped with low-thrust rocket engines. We propose a control strategy that allows the stabilization of the nominal spin state and demonstrate the system's proper operation by numerically simulating its controlled motion. The discussed multi-tethered formations could be employed, for example, to provide co-location of several satellites at a slot in geostationary orbit.

  4. Your Guide to Healthy Eating Using the Food Pyramid

    OpenAIRE

    Department of Health

    2012-01-01

    Do you want to feel good and have more energy? Do you want to maintain a healthy weight and help reduce your risk of becoming ill from high blood pressure, high cholesterol, heart disease, type 2 diabetes, cancer and other chronic diseases?Eating healthy food and being physically active are two of the most importantsteps that you can take to improve your health. To help you do this, follow the Healthy Eating Guidelines, use the Food Pyramid Guide and the Physical Activity Guidelines. Cl...

  5. Value Chain and Innovation at the Base of the Pyramid

    DEFF Research Database (Denmark)

    Esko, Siim; Zeromskis, Mindaugas; Hsuan, Juliana

    2013-01-01

    introduced for analysing business readiness in BoP: organisation, value chain and strategy. Four diverse cases were analysed: GE’s reverse innovation project, GrameenPhone, Essilor, and P&G’s PuR. Findings – BoP project should be a top-down supported separate entity with its own strategic processes and......Purpose – This paper aims to investigate the factors a multinational corporation should adapt when doing business at the bottom of the pyramid (BoP) markets. Design/methodology/approach – Based on a systematic literature review on BoP, value chain and innovation, an integrative framework is...

  6. Effects of Arc/Arg3.1 gene deletion on rhythmic synchronization of hippocampal CA1 neurons during locomotor activity and sleep.

    Science.gov (United States)

    Malkki, Hemi A I; Mertens, Paul E C; Lankelma, Jan V; Vinck, Martin; van Schalkwijk, Frank J; van Mourik-Donga, Laura B; Battaglia, Francesco P; Mahlke, Claudia; Kuhl, Dietmar; Pennartz, Cyriel M A

    2016-05-01

    The activity-regulated cytoskeletal-associated protein/activity regulated gene (Arc/Arg3.1) is crucial for long-term synaptic plasticity and memory formation. However, the neurophysiological substrates of memory deficits occurring in the absence of Arc/Arg3.1 are unknown. We compared hippocampal CA1 single-unit and local field potential (LFP) activity in Arc/Arg3.1 knockout and wild-type mice during track running and flanking sleep periods. Locomotor activity, basic firing and spatial coding properties of CA1 cells in knockout mice were not different from wild-type mice. During active behavior, however, knockout animals showed a significantly shifted balance in LFP power, with a relative loss in high-frequency (beta-2 and gamma) bands compared to low-frequency bands. Moreover, during track-running, knockout mice showed a decrease in phase locking of spiking activity to LFP oscillations in theta, beta and gamma bands. Sleep architecture in knockout mice was not grossly abnormal. Sharp-wave ripples, which have been associated with memory consolidation and replay, showed only minor differences in dynamics and amplitude. Altogether, these findings suggest that Arc/Arg3.1 effects on memory formation are not only manifested at the level of molecular pathways regulating synaptic plasticity, but also at the systems level. The disrupted power balance in theta, beta and gamma rhythmicity and concomitant loss of spike-field phase locking may affect memory encoding during initial storage and memory consolidation stages. PMID:27038743

  7. TRPM4-dependent post-synaptic depolarization is essential for the induction of NMDA receptor-dependent LTP in CA1 hippocampal neurons.

    Science.gov (United States)

    Menigoz, Aurélie; Ahmed, Tariq; Sabanov, Victor; Philippaert, Koenraad; Pinto, Silvia; Kerselaers, Sara; Segal, Andrei; Freichel, Marc; Voets, Thomas; Nilius, Bernd; Vennekens, Rudi; Balschun, Detlef

    2016-04-01

    TRPM4 is a calcium-activated but calcium-impermeable non-selective cation (CAN) channel. Previous studies have shown that TRPM4 is an important regulator of Ca(2+)-dependent changes in membrane potential in excitable and non-excitable cell types. However, its physiological significance in neurons of the central nervous system remained unclear. Here, we report that TRPM4 proteins form a CAN channel in CA1 neurons of the hippocampus and we show that TRPM4 is an essential co-activator of N-methyl-D-aspartate (NMDA) receptors (NMDAR) during the induction of long-term potentiation (LTP). Disrupting the Trpm4 gene in mice specifically eliminates NMDAR-dependent LTP, while basal synaptic transmission, short-term plasticity, and NMDAR-dependent long-term depression are unchanged. The induction of LTP in Trpm4 (-/-) neurons was rescued by facilitating NMDA receptor activation or post-synaptic membrane depolarization. Accordingly, we obtained normal LTP in Trpm4 (-/-) neurons in a pairing protocol, where post-synaptic depolarization was applied in parallel to pre-synaptic stimulation. Taken together, our data are consistent with a novel model of LTP induction in CA1 hippocampal neurons, in which TRPM4 is an essential player in a feed-forward loop that generates the post-synaptic membrane depolarization which is necessary to fully activate NMDA receptors during the induction of LTP but which is dispensable for the induction of long-term depression (LTD). These results have important implications for the understanding of the induction process of LTP and the development of nootropic medication. PMID:26631168

  8. Effect of ischemic preconditioning on the expression of c-myb in the CA1 region of the gerbil hippocampus after ischemia/reperfusion injury

    Directory of Open Access Journals (Sweden)

    Hui Young Lee

    2016-06-01

    Conclusion: Our results show that a lethal transient ischemia significantly decreased c-myb immunoreactivity in the SP of the CA1 region and that IPC well preserved c-myb immunoreactivity in the SP of the CA1 region. We suggest that the maintenance of c-myb might be related with IPC-mediated neuroprotection after a lethal ischemic insult.

  9. Morphological evolution of GaN nano-pyramids grown by using metal-organic chemical vapor deposition

    International Nuclear Information System (INIS)

    High-density GaN nano-pyramids were grown on a nano-sized SiO2 pattern, and their morphological evolution was characterized. The effect of the growth temperature was studied with respect to pyramidal growth and was analyzed based on the growth rate anisotropy among crystal planes. At 750 .deg. C, uniform nano-pyramids surrounded by (1101) facets were easily formed due to the large growth rate anisotropy of the planes while the pyramids showed smooth surfaces at 950 .deg. C. We observed that a low growth temperature was beneficial in suppressing the growths of giant pyramids formed by the coalescence of several smaller pyramids.

  10. Indentation size effect in spherical and pyramidal indentations

    International Nuclear Information System (INIS)

    The indentation size effect (ISE) is studied for spherical and pyramidal indentations on a Ni poly-crystal. The indentation experiments were conducted using a Berkovich geometry as well as different spherical indenters with radii of 0.38, 3.8 and 51.0 μm. A strong ISE is observed for the material yielding a higher hardness at smaller depths or smaller sphere radii. The transition from elastic to plastic behaviour is associated with a pop-in in the load-displacement curve, in contrast to the conventional elastic-plastic transition as discussed by Tabor. The indentation response is modelled using Tabor's approach in conjunction with the uniaxial macroscopic stress-strain behaviour for calculating the statistically stored dislocation density for a given indenter geometry. The geometrically necessary dislocation (GND) density is calculated using a modified Nix/Gao approach, whereas the storage volume for GNDs is used as a parameter for the measured depth dependence of hardness. It will be shown that the ISE for both pyramidal and spherical indentations is related and can be understood within the same given framework. The indentation response of metallic materials can thus be modelled from pop-in to macroscopic hardness

  11. Path-search in the pyramid and in other graphs

    CERN Document Server

    Gerbner, Dániel

    2011-01-01

    We are given an acyclic directed graph with one source, and a subset of its edges which contains exactly one outgoing edge for every non-sink vertex. These edges determine a unique path from the source to a sink. We can think of it as a switch in every vertex, which determines which way the water arriving to that vertex flows further. We are interested in determining either the sink the flow arrives, or the whole path, with as few questions as possible. The questions we can ask correspond to the vertices of the graph, and the answer describes the switch, i.e. tells which outgoing edge is in our given subset. Originally the problem was proposed by Soren Riis (who posed the question for pyramid graphs) in the following more general form. We are given a natural number k, and k questions can be asked in a round. The goal is to minimize the number of rounds. We completely solve this problem for complete t-ary trees. Also, for pyramid graphs we present some non-trivial partial results.

  12. Loss of glutathione homeostasis associated with neuronal senescence facilitates TRPM2 channel activation in cultured hippocampal pyramidal neurons

    Directory of Open Access Journals (Sweden)

    Belrose Jillian C

    2012-04-01

    Full Text Available Abstract Background Glutathione (GSH plays an important role in neuronal oxidant defence. Depletion of cellular GSH is observed in neurodegenerative diseases and thereby contributes to the associated oxidative stress and Ca2+ dysregulation. Whether depletion of cellular GSH, associated with neuronal senescence, directly influences Ca2+ permeation pathways is not known. Transient receptor potential melastatin type 2 (TRPM2 is a Ca2+ permeable non-selective cation channel expressed in several cell types including hippocampal pyramidal neurons. Moreover, activation of TRPM2 during oxidative stress has been linked to cell death. Importantly, GSH has been reported to inhibit TRPM2 channels, suggesting they may directly contribute to Ca2+ dysregulation associated with neuronal senescence. Herein, we explore the relation between cellular GSH and TRPM2 channel activity in long-term cultures of hippocampal neurons. Results In whole-cell voltage-clamp recordings, we observe that TRPM2 current density increases in cultured pyramidal neurons over time in vitro. The observed increase in current density was prevented by treatment with NAC, a precursor to GSH synthesis. Conversely, treatment of cultures maintained for 2 weeks in vitro with L-BSO, which depletes GSH by inhibiting its synthesis, augments TRPM2 currents. Additionally, we demonstrate that GSH inhibits TRPM2 currents through a thiol-independent mechanism, and produces a 3.5-fold shift in the dose-response curve generated by ADPR, the intracellular agonist for TRPM2. Conclusion These results indicate that GSH plays a physiologically relevant role in the regulation of TRPM2 currents in hippocampal pyramidal neurons. This interaction may play an important role in aging and neurological diseases associated with depletion of GSH.

  13. The Conflict Pyramid: A Holistic Approach to Structuring Conflict Resolution in Schools

    Science.gov (United States)

    Hakvoort, Ilse

    2010-01-01

    This paper examines how the conflict pyramid, originally defined and used by Richard Cohen, can be used as a model to describe the relations between different conflict resolution education programs and activities included in the programs. The central questions posed in the paper are: How can Richard Cohen's conflict pyramid be used as a model for…

  14. Pyramidal anchor stone from Baga waters of Goa, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Tripati, S.

    . Pyramidal anchor stones have an apex hole which goes up to the round hole, however Goa anchor stone has no such perforation, but, instead has a rectangular cutting on the apex. The anchor stone is compared with Greek pyramidal anchor stones, and probably...

  15. Morphological pyramids in multiresolution MIP rendering of large volume data: Survey and new results

    OpenAIRE

    Roerdink, J. B. T. M.

    2005-01-01

    We survey and extend nonlinear signal decompositions based on morphological pyramids, and their application to multiresolution maximum intensity projection (MIP) volume rendering with progressive refinement and perfect reconstruction. The structure of the resulting multiresolution rendering algorithm is very similar to wavelet splatting. Several existing classes of pyramids are discussed, and their limitations indicated. To enhance the approximation quality of visualizations from reduced data...

  16. Renal pyramid echogenicity in ureteropelvic junction obstruction: correlation between altered echogenicity and differential renal function

    International Nuclear Information System (INIS)

    Improvement in resolution and use of high-frequency transducers in US has enabled visualization of previously unreported changes in medullary pyramid echogenicity in children with obstructive hydronephrosis. To determine whether these unreported changes in echogenicity and morphology of the renal pyramids in ureteropelvic junction (UPJ) obstruction correlate with differential renal function (DRF) of the kidney as determined by technetium-99m mercaptoacetyltriglycine (99mTc-MAG3) scan. Renal sonograms in 60 children with UPJ obstruction were retrospectively reviewed. Children were divided into three groups based on the echogenicity of the pyramids: (1) normal echogenicity of the pyramids, (2) increased echogenicity of the pyramids with maintained corticomedullary differentiation (CMD), and (3) loss of CMD. DRF, as determined by 99mTc-MAG3 scan, of the obstructed kidney of ≥45% was considered normal and of ≤44% was considered abnormal based on a published study correlating histological changes with DRF. Fisher's exact test was performed for assessing the association between DRF and altered echogenicity of the pyramids. In group 1, which consisted of 13 patients with normal pyramids on US, DRF was normal in 11 and abnormal in two. In group 2, which consisted of 33 patients with echogenic pyramids and preserved CMD, DRF was normal in 15 and abnormal in 18. In group 3, which consisted of 14 patients with complete loss of CMD, DRF was normal in 2 and abnormal in 12. There was a strong correlation between abnormal pyramids and DRF (P=0.0009). The risk ratio (RR) of DRF becoming abnormal for those kidneys with abnormal echogenicity of the pyramids with preserved CMD (group 2) compared to normal pyramid echogenicity (group 1) was 1.56 (95% CI 1.088-2.236). The RR of DRF becoming abnormal for those kidneys with loss of CMD (group 3) compared to normal pyramid echogenicity (group 1) was 5.571 (95% CI 1.530-20.294). We observed that in obstructed kidneys the echogenicity

  17. Ca 1- xNa xIrO 3 as a novel quasi-two-dimensional Mott transition system

    Science.gov (United States)

    Ohgushi, Kenya; Gotou, Hirotada; Yagi, Takehiko; Kiuchi, Yoko; Sakai, Fumiko; Ueda, Yutaka

    2007-09-01

    We have successfully synthesized Ca1-xNaxIrO3 with the post-perovskite structure and elucidated their electronic properties. CaIrO3 is a S = 1/2 antiferromagnetic Mott insulator with the Néel temperature (TN) of 115 K. A gradual decrease in TN upon carrier doping culminates in a paramagnetic state at x ∼ 0.3 with the simultaneous change from an insulator to a metal. The metallic state for x ⩾ 0.31 shows the non-Fermi liquid behavior originating from antiferromagnetic fluctuations.

  18. The structure and piezoelectric properties of (Ca1-xSrx)Bi4Ti4O15 ceramics

    International Nuclear Information System (INIS)

    In this paper, the structure and piezoelectric properties of (Ca1-xSrx)Bi4Ti4O15 ceramics (x=0-1.0) are investigated. The formation of single orthorhombic phase is verified by XRD. The dependence of dielectric and piezoelectric properties on x is also determined. The results show that the excellent properties could be found in the composition of x=0.4. In that composition, d33=14.9, TC=677 deg. C and the DC resistivity is decuplely higher than that of BST (SrBi4Ti4O15) and CBT (CaBi4Ti4O15)

  19. Effects of Fe doping in La1/2Ca1/2MnO3

    OpenAIRE

    Levy, P.; Granja, L.; Indelicato, E.; Vega, D.; Polla, G.; Parisi, F.

    2000-01-01

    The effect of Fe doping in the Mn site on the magnetic, transport and structural properties of polycrystalline La1/2Ca1/2MnO3 was studied. Doping with low Fe concentration (< 10%) strongly affects electrical transport and magnetization. Long range charge order is disrupted even for the lowest doping level studied (~2%). For Fe concentration up to 5% a ferromagnetic state develops at low temperature with metallic like conduction and thermal hysteresis. In this range, the Curie temperature decr...

  20. Variation around a Pyramid theme: optical recombination and optimal use of photons

    CERN Document Server

    Fauvarque, O; Fusco, T; Sauvage, J F

    2015-01-01

    We propose a new type of Wave Front Sensor (WFS) derived from the Pyramid WFS (PWFS). This new WFS, called the Flattened Pyramid-WFS (FPWFS), has a reduced Pyramid angle in order to optically overlap the four pupil images into an unique intensity. This map is then used to derive the phase information. In this letter this new WFS is compared to three existing WFSs, namely the PWFS, the Modulated PWFS (MPWFS) and the Zernike WFS (ZWFS) following tests about sensitivity, linearity range and low photon flux behavior. The FPWFS turns out to be more linear than a modulated pyramid for the high-spatial order aberrations but it provides an improved sensitivity compared to the non-modulated pyramid. The noise propagation may even be as low as the ZWFS for some given radial orders. Furthermore, the pixel arrangement being more efficient than for the PWFS, the FPWFS seems particularly well suited for high-contrast applications.

  1. The architectonic encoding of the minor lunar standstills in the horizon of the Giza pyramids.

    Science.gov (United States)

    Hossam, M. K. Aboulfotouh

    The paper is an attempt to show the architectonic method of the ancient Egyptian designers for encoding the horizontal-projections of the moon's declinations during two events of the minor lunar standstills, in the design of the site-plan of the horizon of the Giza pyramids, using the methods of descriptive geometry. It shows that the distance of the eastern side of the second Giza pyramid from the north-south axis of the great pyramid encodes a projection of a lunar declination, when earth's obliquity-angle was ~24.10°. Besides, it shows that the angle of inclination of the causeway of the second Giza pyramid, of ~13.54° south of the cardinal east, encodes the projection of another lunar declination when earth's obliquity-angle reaches ~22.986°. In addition, it shows the encoded coordinate system in the site-plan of the horizon of the Giza pyramids.

  2. GaAs micro-pyramids serving as optical micro-cavities

    International Nuclear Information System (INIS)

    An efficient light-matter coupling requires high-quality (Q) micro-cavities with small mode volume. We suggest GaAs micro-pyramids placed on top of AlAs/GaAs distributed Bragg reflectors to be promising candidates. The pyramids were fabricated by molecular-beam epitaxy, electron-beam lithography and a subsequent wet-chemical etching process using a sacrificial AlAs layer. Measured Q-factors of optical modes in single pyramids reach values up to 650. A finite-difference time-domain simulation assuming a simplified cone-shaped geometry suggests possible Q-factors up to 3600. To enhance the light confinement in the micro-pyramids we intend to overgrow the pyramidal facets with a Bragg mirror--results of preliminary tests are given.

  3. Investigation on the change of nitric oxide synthetase positive neurons in hippocampus CA1 area of rats with hyperglycemia%高血糖大鼠海马CA1区一氧化氮合成酶阳性神经元变化的研究

    Institute of Scientific and Technical Information of China (English)

    周郦楠; 王冶; 孙永杰

    2002-01-01

    Objective To observe the expression of nitric oxide syhthetase(NOS) in hippocampus CA1 neurons with hyperglycemia.Method NADPH-d histochemical method was used.Rcsults NOS positive neurons expressed in hippocampus CA1 and nomal neurons of 6 weeks old rats with hyperglycemia(DM) and normal rats(NC).There was significant difference in neurons between DM group and control group.Conclusion NOS positive neurons decrease in hippocampus CA1 of rats with hyperglycemia.

  4. Properties of BK-type Ca++-dependent K+ channel currents in medial prefrontal cortex (PFC pyramidal neurons in rats of different ages

    Directory of Open Access Journals (Sweden)

    Bartłomiej Paweł Szulczyk

    2013-10-01

    Full Text Available The medial prefrontal cortex (PFC is involved in cognitive functions, which undergo profound changes during adolescence. This alteration of the PFC function derives from neuron activity, which, in turn, may depend on age-dependent properties and the expression of neuronal ion channels. BK-type channels are involved in controlling both the Ca++ ion concentration in the cell interior and cell excitability. The purpose of this study was to test the properties of BK currents in the medial PFC pyramidal neurons of young (18–22-day-old, adolescent (38–42-day-old and adult (58–62-day-old rats. Whole-cell currents evoked by depolarizing voltage steps were recorded from dispersed medial PFC pyramidal neurons. A selective BK channel blocker – paxilline (10 µM – irreversibly decreased the non-inactivating K+ current in neurons that were isolated from the young and adult rats. This current was not significantly affected by paxilline in the neurons obtained from adolescent rats. The properties of single-channel K+ currents were recorded from the soma of dispersed medial PFC pyramidal neurons in the cell-attached configuration. Of the K+ channel currents that were recorded, ~90% were BK and leak channel currents. The BK-type channel currents were dependent on the Ca++ concentration and the voltage and were inhibited by paxilline. The biophysical properties of the BK channel currents did not differ among the pyramidal neurons isolated from young, adolescent and adult rats. Among all of the recorded K+ channel currents, 38.9%, 12.7% and 21.1% were BK-type channel currents in the neurons isolated from the young, adolescent and adult rats, respectively. Furthermore, application of paxilline effectively prolonged the half-width of the action potential in pyramidal neurons in slices isolated from young and adult rats but not in neurons isolated from adolescent rats. We conclude that the availability of BK channel currents decreases in medial PFC

  5. RNA interference of Marlin-1/Jakmip1 results in abnormal morphogenesis and migration of cortical pyramidal neurons.

    Science.gov (United States)

    Vidal, René L; Fuentes, Patricio; Valenzuela, José Ignacio; Alvarado-Diaz, Carlos P; Ramírez, Omar A; Kukuljan, Manuel; Couve, Andrés

    2012-08-01

    The formation of the nervous systems requires processes that coordinate proliferation, differentiation and migration of neuronal cells, which extend axons, generate dendritic branching and establish synaptic connections during development. The structural organization and dynamic remodeling of the cytoskeleton and its association to the secretory pathway are critical determinants of cell morphogenesis and migration. Marlin-1 (Jakmip1) is a microtubule-associated protein predominantly expressed in neurons and lymphoid cells. Marlin-1 participates in polarized secretion in lymphocytes, but its functional association with the neuronal cytoskeleton and its contribution to brain development have not been explored. Combining in vitro and in vivo approaches we show that Marlin-1 contributes to the establishment of neuronal morphology. Marlin-1 associates to the cytoskeleton in neurites, is required for the maintenance of an intact Golgi apparatus and its depletion produces the down-regulation of kinesin-1, a plus-end directed molecular motor with a central function in morphogenesis and migration. RNA interference of Marlin-1 in vivo results in abnormal migration of newborn pyramidal neurons during the formation of the cortex. Our results support the involvement of Marlin-1 in the acquisition of the complex architecture and migration of pyramidal neurons, two fundamental processes for the laminar layering of the cortex. PMID:22828129

  6. Layer- and column-specific knockout of NMDA receptors in pyramidal neurons of the mouse barrel cortex.

    Directory of Open Access Journals (Sweden)

    Rachel Aronoff

    2007-11-01

    Full Text Available Viral vectors injected into the mouse brain offer the possibility for localized genetic modifications in a highly controlled manner. Lentivector injection into mouse neocortex transduces cells within a diameter of approximately 200µm, which closely matches the lateral scale of a column in barrel cortex. The depth and volume of the injection determines which cortical layer is transduced. Furthermore, transduced gene expression from the lentivector can be limited to predominantly pyramidal neurons by using a 1.3kb fragment of the αCaMKII promoter. This technique therefore allows genetic manipulation of a specific cell type in defined columns and layers of the neocortex. By expressing Cre recombinase from such a lentivector in gene-targeted mice carrying a floxed gene, highly specific genetic lesions can be induced. Here, we demonstrate the utility of this approach by specifically knocking out NMDA receptors (NMDARs in pyramidal neurons in the somatosensory barrel cortex of gene-targeted mice carrying floxed NMDAR 1 genes. Neurons transduced with lentivector encoding GFP and Cre recombinase exhibit not only reductions in NMDAR 1 mRNA levels, but reduced NMDAR-dependent currents and pairing-induced synaptic potentiation. This technique for knockout of NMDARs in a cell type, column- and layer-specific manner in the mouse somatosensory cortex may help further our understanding of the functional roles of NMDARs in vivo during sensory perception and learning.

  7. Succeeding at the Bottom-of-the-Pyramid

    DEFF Research Database (Denmark)

    Boxenbaum, Eva; Olsen, Mette

    Hybrid organizational forms often rely on the initiative or collaboration of corporate actors, yet the role of these actors is rarely examined in detail. This paper examines corporate social entrepreneurship, which refers to the initiative of corporate actors to establish new, independent social...... ventures in the double pursuit of financial objectives and wider societal objectives. Through an empirical study, we investigate the strategies and practices that corporate social entrepreneurs employ to build radically new social ventures outside their firm. More specifically, we examine a successful...... initiative to build a social impact venture at the interface of a multi-national corporation and a hybrid organization that is operating on the Bottom-of-the-Pyramid market. Our study identifies how corporate social entrepreneurs dynamically use framing and organizational anchoring strategies to build...

  8. Photocurrent spectroscopy of site-controlled pyramidal quantum dots

    Science.gov (United States)

    Mohan, A.; Nevou, L.; Gallo, P.; Dwir, B.; Rudra, A.; Kapon, E.; Faist, J.

    2012-07-01

    Intraband photocurrent spectroscopy of site-controlled pyramidal quantum dots by inserting them into the intrinsic region of n-i-n like quantum dot infrared photodetector structure is reported. The photovoltaic response is observed in the mid-infrared region. A peak responsivity of 0.4 mA/W at 120 meV (λ = 10 μm) is observed at 10 K at -2 V bias. The ability to engineer states in the conduction band of the QDs has been exploited to tune their photocurrent response from 10 μm to 18 μm with a narrow spectral width of Δλ/λ = 0.17.

  9. Silicon sensors with pyramidal structures for neutron imaging

    Science.gov (United States)

    Kok, A.; Kohout, Z.; Hansen, T.-E.; Petersson, S.; Pospisil, S.; Rokne, J.; Slavicek, T.; Soligard, S.; Thungstrom, G.; Vykydal, Z.

    2014-04-01

    Neutron detection is a valuable tool in nuclear science research, homeland security, quality assurance in nuclear plants and medical applications. Recent developments and near future instrumentations in neutron imaging have a need for sensors with high spatial resolution, dynamic range, sensitivity and background discrimination. Silicon based neutron detectors can potentially fulfil these requirements. In this work, pad and pixel detectors with pyramidal micro-structures have been successfully fabricated that should have an improved detection efficiency when compared to conventional planar devices. Titanium di-boride (TiB2) and lithium fluoride (LiF) were deposited as the neutron converters. Excellent electrical performances were measured on both simple pad and pixel detectors. A selection of pad detectors was examined by alpha spectroscopy. Measurement with thermal neutrons from a 241Am-Be source shows an improvement in relative efficiency of up to 38% when compared to conventional planar devices.

  10. Silicon sensors with pyramidal structures for neutron imaging

    International Nuclear Information System (INIS)

    Neutron detection is a valuable tool in nuclear science research, homeland security, quality assurance in nuclear plants and medical applications. Recent developments and near future instrumentations in neutron imaging have a need for sensors with high spatial resolution, dynamic range, sensitivity and background discrimination. Silicon based neutron detectors can potentially fulfil these requirements. In this work, pad and pixel detectors with pyramidal micro-structures have been successfully fabricated that should have an improved detection efficiency when compared to conventional planar devices. Titanium di-boride (TiB2) and lithium fluoride (LiF) were deposited as the neutron converters. Excellent electrical performances were measured on both simple pad and pixel detectors. A selection of pad detectors was examined by alpha spectroscopy. Measurement with thermal neutrons from a 241Am-Be source shows an improvement in relative efficiency of up to 38% when compared to conventional planar devices

  11. Pyramide des âges et gestion des ressources humaines

    OpenAIRE

    Godelier, Eric

    2007-01-01

    L'utilisation de la pyramide des âges dans les discours des directeurs de ressources humaines s'est développée au cours des années 1980. Elle renvoie au choix d'un critère de sélection de salariés jugés en sureffectif. Derrière l'âge et ses représentations, c'est bien la question de la capacité des salariés à s'adapter au changement de l'entreprise qui est posée. En définitive, il s'agit de savoir s'il existe des conditions démographiques au changement organisationnel.

  12. Mediterranean Diet Pyramid: A Proposal for Italian People

    Directory of Open Access Journals (Sweden)

    Annunziata D'Alessandro

    2014-10-01

    Full Text Available Bread was a staple in the traditional Mediterranean diet of the early 1960s, as well as nowadays; however, it was a stone ground sourdough bread in Nicotera and probably in the Greek cohorts of the Seven Countries Study. In the present review, the nutritional characteristics of this food are analyzed in relation to its protective effects on coronary heart disease, metabolic diseases and cancer. According to our traditions, cultural heritage and scientific evidence, we propose that only cereal foods with low glycemic index (GI and rich in fiber have to be placed at the base of the Mediterranean diet pyramid, whereas refined grains and high GI starchy foods have to be sited at the top.

  13. Mediterranean diet pyramid: a proposal for Italian people.

    Science.gov (United States)

    D'Alessandro, Annunziata; De Pergola, Giovanni

    2014-10-01

    Bread was a staple in the traditional Mediterranean diet of the early 1960s, as well as nowadays; however, it was a stone ground sourdough bread in Nicotera and probably in the Greek cohorts of the Seven Countries Study. In the present review, the nutritional characteristics of this food are analyzed in relation to its protective effects on coronary heart disease, metabolic diseases and cancer. According to our traditions, cultural heritage and scientific evidence, we propose that only cereal foods with low glycemic index (GI) and rich in fiber have to be placed at the base of the Mediterranean diet pyramid, whereas refined grains and high GI starchy foods have to be sited at the top. PMID:25325250

  14. Clinical results of neurotransmission SPECT in extra-pyramidal diseases

    International Nuclear Information System (INIS)

    We present some methodological aspects and clinical applications of dopamine D2 receptor and transporter SPECT using new radiotracers radiolabeled with iodine 123. The gamma camera quality control and standardisation has to be adapted to the small volume and deep location of striata, where receptors and transporters are present. Phantom containing hollow spheres of different diameters which can be filled with different amounts of 99mTc or 123I. The semi quantitation of receptor and transporter molecular concentration is based on an equilibrium binding model. According to this model, the binding potential (Bmax. Ka) is equal to the ratio between specific binding in the striatum and circulating activity in a reference region of interest in the occipital cortex. By comparing ECD and ILIS SPECT, it has been shown that striatal ILIS binding does not depend on the local perfusion. The clinical applications mainly concern the extra-pyramidal pathology: ILIS and IBZM SPECT are able to differentiate pre- and post-synaptic lesions. In Parkinson disease the nigrostriatal pathway is damaged and D2 receptors are normal or increased, as shown by normal or elevated IBZM or ILIS uptake. In other extra pyramidal degenerative diseases as progressive supra nuclear palsy or multiple system atrophy striatal D2 receptors are damaged as shown by decreased IBZM or ILIS uptake. In our experience, 88 per cent of patients are correctly classified by ILIS SPECT and 86 per cent with IBZM SPECT. Dopamine transporter SPECT with βCIT and PE2I provides an evaluation of the presynaptic neuronal density in the striatum. One can expect an help for the early diagnosis and the evaluation of Parkinson disease. Another potential application of dopaminergic neurotransmission SPECT is the evaluation of neuronal loss after hypoxo-ischemia. We conclude that dopaminergic neurotransmission SPECT using specific ligands should become a useful diagnosis tool to study a large number of brain dysfunctions. (author)

  15. Active appearance pyramids for object parametrisation and fitting.

    Science.gov (United States)

    Zhang, Qiang; Bhalerao, Abhir; Dickenson, Edward; Hutchinson, Charles

    2016-08-01

    Object class representation is one of the key problems in various medical image analysis tasks. We propose a part-based parametric appearance model we refer to as an Active Appearance Pyramid (AAP). The parts are delineated by multi-scale Local Feature Pyramids (LFPs) for superior spatial specificity and distinctiveness. An AAP models the variability within a population with local translations of multi-scale parts and linear appearance variations of the assembly of the parts. It can fit and represent new instances by adjusting the shape and appearance parameters. The fitting process uses a two-step iterative strategy: local landmark searching followed by shape regularisation. We present a simultaneous local feature searching and appearance fitting algorithm based on the weighted Lucas and Kanade method. A shape regulariser is derived to calculate the maximum likelihood shape with respect to the prior and multiple landmark candidates from multi-scale LFPs, with a compact closed-form solution. We apply the 2D AAP on the modelling of variability in patients with lumbar spinal stenosis (LSS) and validate its performance on 200 studies consisting of routine axial and sagittal MRI scans. Intervertebral sagittal and parasagittal cross-sections are typically used for the diagnosis of LSS, we therefore build three AAPs on L3/4, L4/5 and L5/S1 axial cross-sections and three on parasagittal slices. Experiments show significant improvement in convergence range, robustness to local minima and segmentation precision compared with Constrained Local Models (CLMs), Active Shape Models (ASMs) and Active Appearance Models (AAMs), as well as superior performance in appearance reconstruction compared with AAMs. We also validate the performance on 3D CT volumes of hip joints from 38 studies. Compared to AAMs, AAPs achieve a higher segmentation and reconstruction precision. Moreover, AAPs have a significant improvement in efficiency, consuming about half the memory and less than 10% of

  16. Spatial Pyramid Pooling in Deep Convolutional Networks for Visual Recognition.

    Science.gov (United States)

    He, Kaiming; Zhang, Xiangyu; Ren, Shaoqing; Sun, Jian

    2015-09-01

    Existing deep convolutional neural networks (CNNs) require a fixed-size (e.g., 224 × 224) input image. This requirement is "artificial" and may reduce the recognition accuracy for the images or sub-images of an arbitrary size/scale. In this work, we equip the networks with another pooling strategy, "spatial pyramid pooling", to eliminate the above requirement. The new network structure, called SPP-net, can generate a fixed-length representation regardless of image size/scale. Pyramid pooling is also robust to object deformations. With these advantages, SPP-net should in general improve all CNN-based image classification methods. On the ImageNet 2012 dataset, we demonstrate that SPP-net boosts the accuracy of a variety of CNN architectures despite their different designs. On the Pascal VOC 2007 and Caltech101 datasets, SPP-net achieves state-of-the-art classification results using a single full-image representation and no fine-tuning. The power of SPP-net is also significant in object detection. Using SPP-net, we compute the feature maps from the entire image only once, and then pool features in arbitrary regions (sub-images) to generate fixed-length representations for training the detectors. This method avoids repeatedly computing the convolutional features. In processing test images, our method is 24-102 × faster than the R-CNN method, while achieving better or comparable accuracy on Pascal VOC 2007. In ImageNet Large Scale Visual Recognition Challenge (ILSVRC) 2014, our methods rank #2 in object detection and #3 in image classification among all 38 teams. This manuscript also introduces the improvement made for this competition. PMID:26353135

  17. Imidacloprid toxicity impairs spatial memory of echolocation bats through neural apoptosis in hippocampal CA1 and medial entorhinal cortex areas.

    Science.gov (United States)

    Hsiao, Chun-Jen; Lin, Ching-Lung; Lin, Tian-Yu; Wang, Sheue-Er; Wu, Chung-Hsin

    2016-04-13

    It has been reported that the decimation of honey bees was because of pesticides of imidacloprid. The imidacloprid is a wildly used neonicotinoid insecticide. However, whether imidacloprid toxicity interferes with the spatial memory of echolocation bats is still unclear. Thus, we compared the spatial memory of Formosan leaf-nosed bats, Hipposideros terasensis, before and after chronic treatment with a low dose of imidacloprid. We observed that stereotyped flight patterns of echolocation bats that received chronic imidacloprid treatment were quite different from their originally learned paths. We further found that neural apoptosis in hippocampal CA1 and medial entorhinal cortex areas of echolocation bats that received imidacloprid treatment was significantly enhanced in comparison with echolocation bats that received sham treatment. Thus, we suggest that imidacloprid toxicity may interfere with the spatial memory of echolocation bats through neural apoptosis in hippocampal CA1 and medial entorhinal cortex areas. The results provide direct evidence that pesticide toxicity causes a spatial memory disorder in echolocation bats. This implies that agricultural pesticides may pose severe threats to the survival of echolocation bats. PMID:26966783

  18. Effects of pioglitazone injection into hippocampal CA1 area on spatial learning and memory deficits in rats

    Directory of Open Access Journals (Sweden)

    Amir Farshchi

    2010-12-01

    Full Text Available Background: Pioglitazone from thiazolidinediones generation, represent a new antidiabetic drugs that have been introduced in the world recently. Thiazolidinediones can improve insulin resistance by activating the nuclear peroxoxisome proliferator activated receptor-γ (PPAR-γ and increasing insulin sensitivity in their receptors. Insulin and its receptors are found in specific areas of CNS with a variety of region-specific functions. The effects of insulin in CNS are different from its direct glucose regulation in the periphery. Hippocampus and cerebral cortex distributed insulin/insulin receptor have been shown to be involved in brain cognitive functions. In the present study, the effect of pioglitazone microinjection into CA1 region of rat hippocampus using Morris water maze performance has been investigated.Methods: In this experimental study, male N-MRI rats were randomly divided into control, DMF (dimethyl formamide and pioglitazone groups (0.001, 0.01, 0.1, 1, 10 µg/rat. Drugs were injected (1 µl/rat into CA1 region bilaterly during 1 min. Thirty minutes after the intrahippocampal injection of drugs, water maze training was started. Results: Pioglitazone had a dose dependent effect. The spatial learning and memory didn’t change with lower dose of pioglitazone, but improved with intermediate doses, while they impaired with higher dose. Conclusion: These results suggest that intrahippocampal injection of pioglitazone may have a dose-dependent effect on spatial learning and memory in rats in range of 0.001 to 1 µg/rat.

  19. Butylphthalide Suppresses Neuronal Cells Apoptosis and Inhibits JNK-Caspase3 Signaling Pathway After Brain Ischemia /Reperfusion in Rats.

    Science.gov (United States)

    Wen, Xiang-Ru; Tang, Man; Qi, Da-Shi; Huang, Xiao-Jing; Liu, Hong-Zhi; Zhang, Fang; Wu, Jian; Wang, Yi-Wen; Zhang, Xun-Bao; Guo, Ji-Qiang; Wang, Shu-Ling; Liu, Yong; Wang, Yu-Lan; Song, Yuan-Jian

    2016-10-01

    Although Butylphthalide (BP) has protective effects that reduce ischemia-induced brain damage and neuronal cell death, little is known about the precise mechanisms occurring during cerebral ischemia/reperfusion (I/R). Therefore, the aim of this study was to investigate the neuroprotective mechanisms of BP against ischemic brain injury induced by cerebral I/R through inhibition of the c-Jun N-terminal kinase (JNK)-Caspase3 signaling pathway. BP in distilled non-genetically modified Soybean oil was administered intragastrically three times a day at a dosage of 15 mg/(kg day) beginning at 20 min after I/R in Sprague-Dawley rats. Immunohistochemical staining and Western blotting were performed to examine the expression of related proteins, and TUNEL-staining was used to detect the percentage of neuronal apoptosis in the hippocampal CA1 region. The results showed that BP could significantly protect neurons against cerebral I/R-induced damage. Furthermore, the expression of p-JNK, p-Bcl2, p-c-Jun, FasL, and cleaved-caspase3 was also decreased in the rats treated with BP. In summary, our results imply that BP could remarkably improve the survival of CA1 pyramidal neurons in I/R-induced brain injury and inhibit the JNK-Caspase3 signaling pathway. PMID:27015680

  20. Excess influx of Zn(2+) into dentate granule cells affects object recognition memory via attenuated LTP.

    Science.gov (United States)

    Suzuki, Miki; Fujise, Yuki; Tsuchiya, Yuka; Tamano, Haruna; Takeda, Atsushi

    2015-08-01

    The influx of extracellular Zn(2+) into dentate granule cells is nonessential for dentate gyrus long-term potentiation (LTP) and the physiological significance of extracellular Zn(2+) dynamics is unknown in the dentate gyrus. Excess increase in extracellular Zn(2+) in the hippocampal CA1, which is induced with excitation of zincergic neurons, induces memory deficit via excess influx of Zn(2+) into CA1 pyramidal cells. In the present study, it was examined whether extracellular Zn(2+) induces object recognition memory deficit via excess influx of Zn(2+) into dentate granule cells. KCl (100 mM, 2 µl) was locally injected into the dentate gyrus. The increase in intracellular Zn(2+) in dentate granule cells induced with high K(+) was blocked by co-injection of CaEDTA and CNQX, an extracellular Zn(2+) chelator and an AMPA receptor antagonist, respectively, suggesting that high K(+) increases the influx of Zn(2+) into dentate granule cells via AMPA receptor activation. Dentate gyrus LTP induction was attenuated 1 h after KCl injection into the dentate gyrus and also attenuated when KCl was injected 5 min after the induction. Memory deficit was induced when training of object recognition test was performed 1 h after KCl injection into the dentate gyrus and also induced when KCl was injected 5 min after the training. High K(+)-induced impairments of LTP and memory were rescued by co-injection of CaEDTA. These results indicate that excess influx of Zn(2+) into dentate granule cells via AMPA receptor activation affects object recognition memory via attenuated LTP induction. Even in the dentate gyrus where is scarcely innervated by zincergic neurons, it is likely that extracellular Zn(2+) homeostasis is strictly regulated for cognition. PMID:26044210

  1. Epitaxial growth of μm-sized Cu pyramids on silicon

    Science.gov (United States)

    Seyffarth, Susanne; Krebs, Hans-Ulrich

    2010-06-01

    Triangular and quadratic Cu pyramids were epitaxially grown on Si(111) and Si(100) substrates, respectively, by pulsed laser deposition at elevated substrate temperatures above 200°C as well as by post-annealing of closed Cu layers prepared at room temperature. In both cases, three-dimensional pyramids with edge lengths of up to 9 μm were obtained, as observed by scanning electron microscopy and atomic force microscopy. Although the macroscopic shape is a pyramid, microscopically the islands consist of columnar grains (with lateral sizes of only about 50 nm at 260°C). The size and shape of the pyramids can be controlled by the substrate used, the amount of material deposited, and the temperature during deposition or annealing. Additionally, first hints were found that the pyramids can be aligned by structuring the substrate. The formation of such large pyramids is explained by a fast diffusion of Cu atoms on Si over distances of some μm and a high jump probability to higher pyramid layers.

  2. Epitaxial growth of {mu}m-sized Cu pyramids on silicon

    Energy Technology Data Exchange (ETDEWEB)

    Seyffarth, Susanne; Krebs, Hans-Ulrich [University of Goettingen (Germany). Institut fuer Materialphysik

    2010-06-15

    Triangular and quadratic Cu pyramids were epitaxially grown on Si(111) and Si(100) substrates, respectively, by pulsed laser deposition at elevated substrate temperatures above 200 C as well as by post-annealing of closed Cu layers prepared at room temperature. In both cases, three-dimensional pyramids with edge lengths of up to 9 {mu}m were obtained, as observed by scanning electron microscopy and atomic force microscopy. Although the macroscopic shape is a pyramid, microscopically the islands consist of columnar grains (with lateral sizes of only about 50 nm at 260 C). The size and shape of the pyramids can be controlled by the substrate used, the amount of material deposited, and the temperature during deposition or annealing. Additionally, first hints were found that the pyramids can be aligned by structuring the substrate. The formation of such large pyramids is explained by a fast diffusion of Cu atoms on Si over distances of some {mu}m and a high jump probability to higher pyramid layers. (orig.)

  3. New insight into the development of pyramidal structures on bombarded copper surfaces

    International Nuclear Information System (INIS)

    The morphological evolution of pyramids, developed on bombarded Cu surfaces, as a function of consecutive doses of normally incident mass-separated 12 keV Kr+ ions from 2.4 x 1016 up to 3 x 1019 ions/cm2 has been studied. Three types of polycrystalline sample, with initial surface topography due to distinct polishing procedures, were used. Three main conclusions were reached. (a) The presence on the unbombarded surfaces of asperities is very important, there being a 1:1 correlation between pyramids and pre-existing asperities, at least for the surfaces as here prepared. (b) In agreement with the predictions of other authors, all pyramids disappeared at high enough doses with all specimens. Pyramids are therefore not an equilibrium structure. (c) Features with a mushroom-like shape were observed which can, under certain circumstances, be an intermediate stage towards the final pyramidal shapes but are, more generally, an indication of the existence of tertiary effects. The results, taken as a whole, suggest a model based on the evolution of asperities by a combination of primary sputtering with further shape modification due to secondary and tertiary effects, i.e. due to particle trajectories as influenced by the pyramids and the grooves underlying the pyramids. (author)

  4. Activities of Polymyxin B and Cecropin A-Melittin Peptide CA(1-8)M(1-18) against a Multiresistant Strain of Acinetobacter baumannii

    OpenAIRE

    Saugar, José María; Alarcón, Teresa; López-Hernández, Susana; López-Brea, Manuel; Andreu, David; Rivas, Luis

    2002-01-01

    Polymyxin B (PXB) and the cecropin A-melittin hybrid CA(1-8)M(1-18) (KWKLFKKIGIGAVLKVLTTGLPALIS-NH2) were compared for antibiotic activity on reference and multiresistant Acinetobacter baumannii strains. Significant differences for both peptides were observed on their inner membrane interaction and inhibition by environmental factors, supporting the use of CA(1-8)M(1-18) as a potential alternative to PXB against Acinetobacter.

  5. Protein Kinase M[Zeta] Is Essential for the Induction and Maintenance of Dopamine-Induced Long-Term Potentiation in Apical CA1 Dendrites

    Science.gov (United States)

    Navakkode, Sheeja; Sajikumar, Sreedharan; Sacktor, Todd Charlton; Frey, Julietta U.

    2010-01-01

    Dopaminergic D1/D5-receptor-mediated processes are important for certain forms of memory as well as for a cellular model of memory, hippocampal long-term potentiation (LTP) in the CA1 region of the hippocampus. D1/D5-receptor function is required for the induction of the protein synthesis-dependent maintenance of CA1-LTP (L-LTP) through activation…

  6. 术中机械通气对小鼠海马CA1区突触可塑性的影响%Effect of mechanical ventilation on synaptic plasticity in hippocampal CA1 region of mice

    Institute of Scientific and Technical Information of China (English)

    陈婷; 张宗泽; 陈畅; 彭勉; 许鑫; 陈凯; 王焱林

    2015-01-01

    目的 评价术中机械通气对小鼠海马CA1区突触可塑性的影响.方法 健康雄性C57BL/6小鼠36只,8~10周龄,体重20~25 g,采用随机数字表法,将其分成2组(n=18):对照组(C组)和机械通气组(M组).小鼠在麻醉后气管插管并行胫骨骨折切开复位内固定术.C组术后拔除气管导管,放入麻醉箱6h,通入1.5%异氟醚维持麻醉;M组术后继续机械通气6h,吸入1.5%异氟醚维持麻醉.于机械通气结束后2h、1和3d时,取6只小鼠进行恐惧条件化实验,记录僵直时间百分比.于机械通气结束后1d时取6只小鼠开始进行新物体识别实验,第4天时间隔5 min、2h和1d时,计算优先指数.于机械通气结束后1d时处死3只小鼠,取海马组织,电镜下观察海马超微结构,并记录突触数量.于机械通气结束后1d时处死3只小鼠,取全脑组织,进行高尔基染色,测定树突棘密度.结果 与C组比较,M组术后2h和1d时僵直时间百分比降低,不同时间间隔优先指数降低,海马CA1区突触数量减少,顶树突棘密度和基树突棘密度降低(P<0.01).结论 术中机械通气可改变小鼠海马CA1区突触可塑性.%Objective To evaluate the effect of mechanical ventilation on synaptic plasticity in hippocampal CA1 region of mice.Methods Thirty-six male C57BL/6 mice,aged 8-10 weeks,weighing 20-25 g,were randomly divided into 2 groups (n =18 each) using a random number table:control group (group C) and mechanical ventilation group (group M).After anesthesia,endotracheal intubation was carried out,and open reduction and internal fixation was performed after tibial fracture was induced in mice.In C group,the endotracheal tube was removed after operation,and then the mice were exposed to 1.5% isoflurane for 6 h in a chamber.In M group,the mice were mechanically ventilated continuously for 6 h,and 1.5% isoflurane was inhaled to maintain the level of anesthesia.At 2 h and 1 and 3 days after the end of ventilation,6 mice were

  7. Performance of Ca1-xSrxTiO3 as barriers in dielectric barrier discharges with different Sr content

    International Nuclear Information System (INIS)

    Plasma assisted catalytic technology, which uses synergetic technologies between the catalyst and plasma, has attracted much attention over the past several years. Theoretically, permittivity of a dielectric barrier influences the transferred charge of a microdischarge; thus high permittivity can improve the plasma reaction in a dielectric barrier discharge (DBD) plasma reactor. Despite the increased interest in the chemical processes, very little has been reported concerning the influence of materials of a dielectric barrier on DBD plasma reactions, since a high permittivity barrier generally exhibits low fracture strength and low dielectric strength making it break down under strong current pulses. In the present study, Ca1-xSrxTiO3 (0.1 ≤ x ≤ 0.4) which possesses a high permittivity and a high fracture strength was prepared by liquid phase sintering and was used as a dielectric barrier for the destruction of carbon dioxide by a DBD plasma reaction. The permittivity of Ca1-xSrxTiO3 (0.1 ≤ x ≤ 0.4) increased with increasing SrTiO3 content; however, the observed CO2 conversion became greatest using Ca0.8Sr0.2TiO3 and then decreased with increasing SrTiO3 content. These results imply that the reactivity of CO2 destruction does not monotonously increase with increased permittivity of the Ca1-xSrxTiO3 barriers. Both amplitude and density of the current pulses ignited by Ca0.8Sr0.2TiO3 were much greater than that of Ca0.6Sr0.4TiO3. Further, it was confirmed that a plasma reaction uniformly proceeded using the Ca0.8Sr0.2TiO3 barrier, but proceeded non-uniformly using the Ca0.6Sr0.4TiO3 barrier by observing the carbon deposition profiles on the surfaces of the barriers

  8. Transient Receptor Potential Vanilloid 4 Inhibits γ-Aminobutyric Acid-Activated Current in Hippocampal Pyramidal Neurons

    Science.gov (United States)

    Hong, Zhiwen; Tian, Yujing; Qi, Mengwen; Li, Yingchun; Du, Yimei; Chen, Lei; Liu, Wentao; Chen, Ling

    2016-01-01

    The balance between excitatory and inhibitory neurotransmitter systems is crucial for the modulation of neuronal excitability in the central nervous system (CNS). The activation of transient receptor potential vanilloid 4 (TRPV4) is reported to enhance the response of hippocampal glutamate receptors, but whether the inhibitory neurotransmitter system can be regulated by TRPV4 remains unknown. γ-aminobutyric acid (GABA) is the major inhibitory neurotransmitter in the CNS. Here, we show that application of transient receptor potential vanilloid 4 (TRPV4) synthetic (GSK1016790A or 4α-PDD) or endogenous agonist (5,6-EET) inhibited GABA-activated current (IGABA) in hippocampal CA1 pyramidal neurons, which was blocked by specific antagonists of TRPV4 and of GABAA receptors. GSK1016790A increased the phosphorylated AMP-activated protein kinase (p-AMPK) and decreased the phosphorylated protein kinase B (p-Akt) protein levels, which was attenuated by removing extracellular calcium or by a calcium/calmodulin-dependent protein kinase kinase-β antagonist. GSK1016790A-induced decrease of p-Akt protein level was sensitive to an AMPK antagonist. GSK1016790A-inhibited IGABA was blocked by an AMPK antagonist or a phosphatidyl inositol 3 kinase (PI3K) agonist. GSK1016790A-induced inhibition of IGABA was also significantly attenuated by a protein kinase C (PKC) antagonist but was unaffected by protein kinase A or calcium/calmodulin-dependent protein kinase II antagonist. We conclude that activation of TRPV4 inhibits GABAA receptor, which may be mediated by activation of AMPK and subsequent down-regulation of PI3K/Akt signaling and activation of PKC signaling. Inhibition of GABAA receptors may account for the neuronal hyperexcitability caused by TRPV4 activation.

  9. Modulation of hard x-ray beam profiles by Borrmann pyramid

    International Nuclear Information System (INIS)

    Spatial modulation of hard x-ray beam profiles is reported, using the 'Borrmann pyramid' formed in dual Bragg diffraction of a single crystal, where a small angular change of the incident beam is magnified to span the entire pyramid base. As an attempt, it is demonstrated using hard x rays by (1) the linear shift of a micrometer sized mask; (2) the partial blockade of a two micron beam; and (3) the millimeter shadow of a nanoscale gold strip, which shows the potential application of Borrmann pyramids in the form of an enlarged x-ray image

  10. Multi-dimensional pyramidal traveling fronts in the Allen-Cahn equations

    OpenAIRE

    黒川, 由生; Kurokawa, Yu; 谷口, 雅治; Taniguchi, Masaharu

    2011-01-01

    This paper studies traveling front solutions of pyramidal shapes in the Allen-Cahn equation in $\\mathbb{R}^{N}$ with $N\\geq 3$.It is well known that two-dimensional V-form traveling fronts and three-dimensional pyramidal traveling fronts exist and are stable. The aim of this paper is to show that for $N\\geq 4$,there exist $N$-dimensional pyramidal traveling fronts.We construct a supersolution and a subsolution, and find a pyramidaltraveling front solution between them. For the construction o...

  11. Epitaxial growth of μm-sized Cu pyramids on silicon

    OpenAIRE

    Seyffarth, Susanne; Krebs, Hans-Ulrich

    2010-01-01

    Triangular and quadratic Cu pyramids were epitaxially grown on Si(111) and Si(100) substrates, respectively, by pulsed laser deposition at elevated substrate temperatures above 200°C as well as by post-annealing of closed Cu layers prepared at room temperature. In both cases, three-dimensional pyramids with edge lengths of up to 9 μm were obtained, as observed by scanning electron microscopy and atomic force microscopy. Although the macroscopic shape is a pyramid, microscopically the islands ...

  12. Searching for possible hidden chambers in the Pyramid of the Sun

    Science.gov (United States)

    Alfaro, R.; Belmont, E.; Grabski, V.; Manzanilla, L.; Martinez-Davalos, A.; Menchaca-Rocha, A.; Moreno, M.; Sandoval, A.

    The Pyramid of the Sun, at Teotihuacan, Mexico, is being searched for possible hidden chambers, using a muon tracking technique inspired in the experiment carried out by Luis Alvarez over 30 years ago at the Chephren Pyramid, in Giza. A fortunate similarity between this monument and the Pyramid of the Sun is a tunnel, running 8 m below the base and ending close to the symmetry axis, which permits the use muon attenuation measurements. A brief account of the project, including planning, detector design, construction and simulations, as well as the current status of the project is presented

  13. The offset-midpoint traveltime pyramid of P-waves in homogeneous orthorhombic media

    KAUST Repository

    Hao, Qi

    2016-07-18

    The offset-midpoint traveltime pyramid describes the diffraction traveltime of a point diffractor in homogeneous media. We have developed an analytic approximation for the P-wave offset-midpoint traveltime pyramid for homogeneous orthorhombic media. In this approximation, a perturbation method and the Shanks transform were implemented to derive the analytic expressions for the horizontal slowness components of P-waves in orthorhombic media. Numerical examples were shown to analyze the proposed traveltime pyramid formula and determined its accuracy and the application in calculating migration isochrones and reflection traveltime. The proposed offset-midpoint traveltime formula is useful for Kirchhoff prestack time migration and migration velocity analysis for orthorhombic media.

  14. Introduction of a pyramid guiding process for general musculoskeletal physical rehabilitation

    Directory of Open Access Journals (Sweden)

    Stark Timothy W

    2006-06-01

    Full Text Available Abstract Successful instruction of a complicated subject as Physical Rehabilitation demands organization. To understand principles and processes of such a field demands a hierarchy of steps to achieve the intended outcome. This paper is intended to be an introduction to a proposed pyramid scheme of general physical rehabilitation principles. The purpose of the pyramid scheme is to allow for a greater understanding for the student and patient. As the respected Food Guide Pyramid accomplishes, the student will further appreciate and apply supported physical rehabilitation principles and the patient will understand that there is a progressive method to their functional healing process.

  15. CAPS1 stabilizes the state of readily releasable synaptic vesicles to fusion competence at CA3–CA1 synapses in adult hippocampus

    Science.gov (United States)

    Shinoda, Yo; Ishii, Chiaki; Fukazawa, Yugo; Sadakata, Tetsushi; Ishii, Yuki; Sano, Yoshitake; Iwasato, Takuji; Itohara, Shigeyoshi; Furuichi, Teiichi

    2016-01-01

    Calcium-dependent activator protein for secretion 1 (CAPS1) regulates exocytosis of dense-core vesicles in neuroendocrine cells and of synaptic vesicles in neurons. However, the synaptic function of CAPS1 in the mature brain is unclear because Caps1 knockout (KO) results in neonatal death. Here, using forebrain-specific Caps1 conditional KO (cKO) mice, we demonstrate, for the first time, a critical role of CAPS1 in adult synapses. The amplitude of synaptic transmission at CA3–CA1 synapses was strongly reduced, and paired-pulse facilitation was significantly increased, in acute hippocampal slices from cKO mice compared with control mice, suggesting a perturbation in presynaptic function. Morphological analysis revealed an accumulation of synaptic vesicles in the presynapse without any overall morphological change. Interestingly, however, the percentage of docked vesicles was markedly decreased in the Caps1 cKO. Taken together, our findings suggest that CAPS1 stabilizes the state of readily releasable synaptic vesicles, thereby enhancing neurotransmitter release at hippocampal synapses. PMID:27545744

  16. Metal-Insulator Transition in Ca1-xNaxIrO3 with Post-Perovskite Structure

    Science.gov (United States)

    Ohgushi, Kenya; Gotou, Hirotada; Yagi, Takehiko; Kiuchi, Yoko; Sakai, Fumiko; Ueda, Yutaka

    2007-03-01

    We developed a novel solid solution Ca1-xNaxIrO3 (0 CaIrO3, the magnetic long-range order is gradually destabilized, culminating in a paramagnetic state at x > 0.30, with simultaneous change from the insulating to metallic behavior. The temperature dependence of the resistivity for metallic samples exhibits several characteristic features: (1) the T^α dependence with α ˜ 1.2 in the metallic range, (2) the lnT dependence in the weak-localization regime, and (3) the positive magnetoresistance violating the Kohler's rule. These results indicate the anomalous metallic state caused by the strong electron correlation effect is realized on the verge of the Mott transition. [1] Nobuyoshi Miyajima, Kenya Ohgushi, Masaki Ichihara, and Takehiko Yagi, Geophys. Res. Lett. 33, L12302 (2006). [2] K. Ohgushi, H. Gotou, T. Yagi, Y. Kiuchi, F. Sakai, and Y. Ueda, submitted.

  17. Size and receptor density of glutamatergic synapses: a viewpoint from left-right asymmetry of CA3-CA1 connections

    Directory of Open Access Journals (Sweden)

    Yoshiaki Shinohara

    2009-07-01

    Full Text Available Synaptic plasticity is considered to be the main mechanism for learning and memory. Excitatory synapses in the cerebral cortex and hippocampus undergo plastic changes during development and in response to electric stimulation. It is widely accepted that this process is mediated by insertion and elimination of various glutamate receptors. In a series of recent investigations on left-right asymmetry of hippocampal CA3-CA1 synapses, glutamate receptor subunits have been found to have distinctive expression patterns that depend on the postsynaptic density (PSD area. Particularly notable are the GluR1 AMPA receptor subunit and NR2B NMDA receptor subunit, where receptor density has either a supra-linear (GluR1 AMPA or inverse (NR2B NMDAR relationship to the PSD area. We review current understanding of structural and physiological synaptic plasticity and propose a scheme to classify receptor subtypes by their expression pattern with respect to PSD area.

  18. Synthesis and thermal expansion hysteresis of Ca1–SrZr4P6O24

    Indian Academy of Sciences (India)

    Basavaraj Angadi; V M Jali; M T Lagare; N S Kini; A M Umarji

    2002-06-01

    The low thermal expansion ceramic system, Ca1-SrZr4P6O24, for the compositions with = 0, 0.25, 0.50, 0.75 and 1 was synthesized by solid-state reaction. The sintering characteristics were ascertained by bulk density measurements. The fracture surface microstructure examined by scanning electron microscopy showed the average grain size of 2.47 m for all the compositions. The thermal expansion data for these ceramic systems over the temperature range 25–800°C is reported. The sinterability of various solid solutions and the hysteresis in dilatometric behaviour are shown to be related to the crystallographic thermal expansion anisotropy. A steady increase in the amount of porosity and critical grain size with increase in is suggested to explain the observed decrease in the hysteresis.

  19. Effect of intrahippocampal CA1 injection of insulin on spatial learning and memory deficits in diabetic rats

    Directory of Open Access Journals (Sweden)

    Golbarg Ghiasi

    2011-03-01

    Full Text Available Background: Diabetes mellitus is one of the most important diseases in all over the world. Insulin and its receptor are found in specific area of CNS with a variety of regions-specific functions different from its role in direct glucose regulation in the periphery. The hippocampus and cerebral cortex distributed insulin and insulin receptor has been shown to be involved in brain cognitive functions. Previous studies about the effect of insulin on memory in diabetes are controversial and further investigation is necessary.Methods: Seventy male NMRI rats (250-300 g were randomly divided into control, diabetic, saline-saline, saline-insulin (12, 18 or 24 mU, diabetic-saline, diabetic-insulin (12, 18 or 24 mU groups. Diabetes was induced by streptozotocin (65 mg/kg, ip. Saline or insulin were injected bilaterally (1 µl/rat into CA1 region of hippocampus during 1 min. Thirty minutes later, water maze training was performed.Results: Insulin had a dose dependent effect. The spatial learning and memory were impaired with diabetes, and improved by insulin. Escape latency and swimming distance in a water maze in insulin treated animals were significantly lower (P<0.05 than control and diabetic groups. Percentage of time spent by animals in a target quarter in probe trial session showed a significant difference among groups. This difference was significant between insulin treated and the other groups (P<0.05.Conclusions: Our findings suggest that injection of insulin into hippocampal CA1 area may have a dose-dependent effect on spatial learning and memory in diabetic rats.

  20. Phase ambiguity solution with the Pyramid Phasing Sensor

    Science.gov (United States)

    Pinna, E.; Esposito, S.; Puglisi, A.; Pieralli, F.; Myers, R. M.; Busoni, L.; Tozzi, A.; Stefanini, P.

    2006-06-01

    In the technological development for the ELTs, one of the key activities is the phasing and alignment of the primary mirror segments. To achieve the phasing accuracy of a small fraction of the wavelength, an optical sensor is required. In 2005 has been demonstrated that the Pyramid Wavefront Sensor can be employed in closed loop to correct simultaneously piston, tip and tilt errors of segmented mirror. The Pyramid Phasing Sensor (PYPS) is based on the sensing of phase step on the segment edges; this kind of phasing sensors have the common limitation of the signal ambiguity induced by the phase periodicity of πδ/λ on the mirror surface step δ, when the wavelength λ is used for the sensing. In this paper we briefly describe three different techniques that allow to solve the phase ambiguity with PYPS. As first we present experimental results on the two wavelengths closed loop procedure proposed by Esposito in 2001; in the laboratory test the multi-wavelength procedure allowed to exceed the sensor capture range of +/-λ/2 and simultaneously retrieve the differential piston of the 32 mirror segments starting from random positions in a 3.2 λ wavefront range, the maximum allowed by the mirror stroke. Then we propose two new techniques based respectively on the segment and wavelength sweep. The Segment Sweep Technique (SST) has been successfully applied during the experimental tests of PYPS at the William Herschel Telescope, when 13 segments of the NAOMI DM has been phased starting from a random position in a 15λ range. The Wavelength Sweep Technique (WST) has been subject of preliminary tests in the Arcetri laboratories in order to prove the concept. Each technique has different capture range, accuracy and operation time, so that each can solve different tasks required to an optical phasing sensor in the ELT application. More in detail the WST and SST could be used combined for the first mirror phasing when the calibration required for the closed loop operations

  1. The GLP-1 Receptor Agonist Exendin-4 and Diazepam Differentially Regulate GABAA Receptor-Mediated Tonic Currents in Rat Hippocampal CA3 Pyramidal Neurons.

    Directory of Open Access Journals (Sweden)

    Sergiy V Korol

    Full Text Available Glucagon-like peptide-1 (GLP-1 is a metabolic hormone that is secreted in a glucose-dependent manner and enhances insulin secretion. GLP-1 receptors are also found in the brain where their signalling affects neuronal activity. We have previously shown that the GLP-1 receptor agonists, GLP-1 and exendin-4 enhanced GABA-activated synaptic and tonic currents in rat hippocampal CA3 pyramidal neurons. The hippocampus is the centre for memory and learning and is important for cognition. Here we examined if exendin-4 similarly enhanced the GABA-activated currents in the presence of the benzodiazepine diazepam. In whole-cell recordings in rat brain slices, diazepam (1 μM, an allosteric positive modulator of GABAA receptors, alone enhanced the spontaneous inhibitory postsynaptic current (sIPSC amplitude and frequency by a factor of 1.3 and 1.6, respectively, and doubled the tonic GABAA current normally recorded in the CA3 pyramidal cells. Importantly, in the presence of exendin-4 (10 nM plus diazepam (1 μM, only the tonic but not the sIPSC currents transiently increased as compared to currents recorded in the presence of diazepam alone. The results suggest that exendin-4 potentiates a subpopulation of extrasynaptic GABAA receptors in the CA3 pyramidal neurons.

  2. Morphological pyramids in multiresolution MIP rendering of large volume data : Survey and new results

    NARCIS (Netherlands)

    Roerdink, Jos B.T.M.

    2005-01-01

    We survey and extend nonlinear signal decompositions based on morphological pyramids, and their application to multiresolution maximum intensity projection (MIP) volume rendering with progressive refinement and perfect reconstruction. The structure of the resulting multiresolution rendering algorith

  3. Indian Reservations, Pyramid lake tribal boundary, reno/sparks tribal boundary, Published in 2006, Washoe County.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Indian Reservations dataset, was produced all or in part from Published Reports/Deeds information as of 2006. It is described as 'Pyramid lake tribal boundary,...

  4. A muon detector to be installed at the Pyramid of the Sun

    International Nuclear Information System (INIS)

    Is the Pyramid of the Sun at Teotihuacan a mausoleum, or just a ceremonial monument? A similar question inspired Luis Alvarez over 30 years ago to carry out his famous muon detection experiment at the Chephren Pyramid, in Giza. A fortunate similarity between this monument and the Pyramid of the Sun is a tunnel, running 8 m below the base and ending close to the symmetry axis, which allows us to emulate Alvarez in a search for possible hidden chambers in one of the largest pyramids in Latin America. Here we elaborate on what is known about this monument, on a description of the proposed detector design, and its expected performance based on simulations. (Author)

  5. A muon detector to be installed at the Pyramid of the Sun

    Energy Technology Data Exchange (ETDEWEB)

    Alfaro, R.; Belmont M, E.; Cervantes, A.; Grabski, V.; Lopez R, J.M.; Manzanilla, L.; Martinez D, A.; Moreno, M.; Menchaca R, A. [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, A.P. 20-364, 01000 Mexico D.F. (Mexico)

    2003-07-01

    Is the Pyramid of the Sun at Teotihuacan a mausoleum, or just a ceremonial monument? A similar question inspired Luis Alvarez over 30 years ago to carry out his famous muon detection experiment at the Chephren Pyramid, in Giza. A fortunate similarity between this monument and the Pyramid of the Sun is a tunnel, running 8 m below the base and ending close to the symmetry axis, which allows us to emulate Alvarez in a search for possible hidden chambers in one of the largest pyramids in Latin America. Here we elaborate on what is known about this monument, on a description of the proposed detector design, and its expected performance based on simulations. (Author)

  6. The azimuth-dependent offset-midpoint traveltime pyramid in 3D HTI media

    KAUST Repository

    Hao, Qi

    2013-09-22

    Analytical representation of offset-midpoint traveltime equation is very important for pre-stack Kirchhoff migration and velocity inversion in anisotropic media. For VTI media, the offset-midpoint traveltime resembles the shape of Cheop\\'s pyramid. In this study, we extend the offset-midpoint traveltime pyramid to the case of 3D HTI media. We employ the stationary phase method to derive the analytical representation of traveltime equation, and then use Shanks transformation to improve the accuracy of horizontal and vertical slownesses. The traveltime pyramid is derived in both the depth- and time-domain. Numerical examples indicate that the azimuthal characteristics of both the traveltime pyramid and the migration isochrones are very obvious in HTI media due to the effect of anisotropy.

  7. High-order Finite Elements on Pyramids: Approximation Spaces, Unisolvency and Exactness

    OpenAIRE

    Nigam, Nilima; Phillips, Joel

    2010-01-01

    We present a family of high-order finite element approximation spaces on a pyramid, and associated unisolvent degrees of freedom. These spaces consist of rational basis functions. We establish conforming, exactness and polynomial approximation properties.

  8. Plasmon hybridization in pyramidal metamaterials: a route towards ultra-broadband absorption

    CERN Document Server

    Lobet, Michael; Sarrazin, Michael; Deparis, Olivier; Henrard, Luc

    2014-01-01

    Pyramidal metamaterials are currently developed for ultra-broadband absorbers. They consist of periodic arrays of alternating metal/dielectric layers forming truncated square-based pyramids. The metallic layers of increasing lengths play the role of vertically and, to a less extent, laterally coupled plasmonic resonators. Based on detailed numerical simulations, we demonstrate that plasmon hybridization between such resonators helps in achieving ultra-broadband absorption. The dipolar modes of individual resonators are shown to be prominent in the electromagnetic coupling mechanism. Lateral coupling between adjacent pyramids and vertical coupling between alternating layers are proven to be key parameters for tuning of plasmon hybridization. Following optimization, the operational bandwidth of Au/Ge pyramids, i.e. the bandwidth within which absorption is higher than 90%, extends over a 0.2-5.8 micrometers wavelength range, i.e. from UV-visible to mid-infrared, and total absorption (integrated over the operatio...

  9. Rate-distortion optimised video transmission using pyramid vector quantisation.

    Science.gov (United States)

    Bokhari, Syed; Nix, Andrew R; Bull, David R

    2012-08-01

    Conventional video compression relies on interframe prediction (motion estimation), intra frame prediction and variable-length entropy encoding to achieve high compression ratios but, as a consequence, produces an encoded bitstream that is inherently sensitive to channel errors. In order to ensure reliable delivery over lossy channels, it is necessary to invoke various additional error detection and correction methods. In contrast, techniques such as Pyramid Vector Quantisation have the ability to prevent error propagation through the use of fixed length codewords. This paper introduces an efficient rate distortion optimisation algorithm for intra-mode PVQ which offers similar compression performance to intra H.264/AVC and Motion JPEG 2000 while offering inherent error resilience. The performance of our enhanced codec is evaluated for HD content in the context of a realistic (IEEE 802.11n) wireless environment. We show that PVQ provides high tolerance to corrupted data compared to the state of the art while obviating the need for complex encoding tools. PMID:22453639

  10. Quantitative trait loci pyramiding for fruit quality traits in tomato.

    Science.gov (United States)

    Sacco, Adriana; Di Matteo, Antonio; Lombardi, Nadia; Trotta, Nikita; Punzo, Biancavaleria; Mari, Angela; Barone, Amalia

    2013-01-01

    Fruit quality is a major focus for most conventional and innovative tomato breeding strategies, with particular attention being paid to fruit antioxidant compounds. Tomatoes represent a major contribution to dietary nutrition worldwide and a reservoir of diverse antioxidant molecules. In a previous study, we identified two Solanum pennellii introgression lines (IL7-3 and IL12-4) harbouring quantitative trait loci (QTL) that increase the content of ascorbic acid (AsA), phenols and soluble solids (degrees Brix; °Bx) in tomato fruit. The purpose of the present work was to pyramid into cultivated varieties the selected QTL for enhanced antioxidant and °Bx content. To better understand the genetic architecture of each QTL, the two ILs were crossed to the recurrent parent M82 (ILH7-3 and ILH12-4) and between them (ILH7-3+12-4). F1 hybrids (ILH7-3+12-4) were then selfed up to obtain F3 progenies in order to stabilize the favourable traits at the homozygous condition. Species-specific molecular markers were identified for each introgressed region and allowed us to select four F2 genotypes carrying both introgressions at the homozygous condition. The F3 double homozygous plants displayed AsA, total phenols and °Bx content significantly higher than M82. Therefore, they may represent suitable genetic material for breeding schemes aiming to increase antioxidant content in tomato fruit. PMID:23316114

  11. MAP spatial pyramid mean shift for object tracking

    Science.gov (United States)

    Han, Xiaobo; Zhang, Peng; Li, Houqiang

    2010-07-01

    Mean Shift is popular in object tracking due to its simplicity and efficiency. It finds local maximum of the similarity measure between the target model and target candidate, and works well in many situations. However, it suffers from two aspects. First, Mean Shift tracker ignores background knowledge. As a result, it may fail when the background color is similar to that of the target or the initial target region contains too much background. Second, Mean Shift tracker omits the geometric structure with a global color histogram as the target model. Therefore, it may not work in the case of partial occlusion. To solve the first problem, we introduce background color histogram into a MAP formulation. To address the second problem, we divide the target into hierarchical blocks. These blocks are described with a histogram each but tracked as a whole. The two threads lead to a new algorithm, named MAP spatial pyramid (MAP-SP) Mean Shift. The efficiency of MAP-SP Mean Shift is demonstrated via comparative experiments on both standard and our own video sequences

  12. Location-dependent excitatory synaptic interactions in pyramidal neuron dendrites.

    Directory of Open Access Journals (Sweden)

    Bardia F Behabadi

    Full Text Available Neocortical pyramidal neurons (PNs receive thousands of excitatory synaptic contacts on their basal dendrites. Some act as classical driver inputs while others are thought to modulate PN responses based on sensory or behavioral context, but the biophysical mechanisms that mediate classical-contextual interactions in these dendrites remain poorly understood. We hypothesized that if two excitatory pathways bias their synaptic projections towards proximal vs. distal ends of the basal branches, the very different local spike thresholds and attenuation factors for inputs near and far from the soma might provide the basis for a classical-contextual functional asymmetry. Supporting this possibility, we found both in compartmental models and electrophysiological recordings in brain slices that the responses of basal dendrites to spatially separated inputs are indeed strongly asymmetric. Distal excitation lowers the local spike threshold for more proximal inputs, while having little effect on peak responses at the soma. In contrast, proximal excitation lowers the threshold, but also substantially increases the gain of distally-driven responses. Our findings support the view that PN basal dendrites possess significant analog computing capabilities, and suggest that the diverse forms of nonlinear response modulation seen in the neocortex, including uni-modal, cross-modal, and attentional effects, could depend in part on pathway-specific biases in the spatial distribution of excitatory synaptic contacts onto PN basal dendritic arbors.

  13. Thalamocortical input onto layer 5 pyramidal neurons measured using quantitative large-scale array tomography

    OpenAIRE

    Jong-Cheol eRah; Erhan eBas; Jennifer eColonell; Yuriy eMishchenko; Bill eKarsh; Fetter, Richard D.; Myers, Eugene W; Chklovskii, Dmitri B.; Karel eSvoboda; Harris, Timothy D.; Isaac, John T. R.

    2013-01-01

    The subcellular locations of synapses on pyramidal neurons strongly influences dendritic integration and synaptic plasticity. Despite this, there is little quantitative data on spatial distributions of specific types of synaptic input. Here we use array tomography (AT), a high-resolution optical microscopy method, to examine thalamocortical (TC) input onto layer 5 pyramidal neurons. We first verified the ability of AT to identify synapses using parallel electron microscopic analysis of TC syn...

  14. Color center fluorescence and spin manipulation in single crystal, pyramidal diamond tips

    CERN Document Server

    Nelz, Richard; Opaluch, Oliver; Sonusen, Selda; Savenko, Natalia; Podgursky, Vitali; Neu, Elke

    2016-01-01

    We investigate bright fluorescence of nitrogen (NV)- and silicon-vacancy color centers in pyramidal, single crystal diamond tips which are commercially available as atomic force microscope probes. We coherently manipulate NV electronic spin ensembles with $T_2 = 7.7(3)\\,\\mu$s. Color center lifetimes in different tip heights indicate effective refractive index effects and quenching. Using numerical simulations, we verify enhanced photon rates from emitters close to the pyramid apex; a situation promising for scanning probe sensing.

  15. Resonance enhancement effects in Raman-enhancing pyramid-like V-shape groove microstructures

    OpenAIRE

    Mechler, M.; Kukhlevsky, S. V.; Mechler, A.; McNaughton, D

    2009-01-01

    Microscopic pyramidal pits in a reflective surface, a geometry similar to a retroreflector, are frequently used to enhance signal strength. The enhancement effect is generally attributed to surface plasmons, however, the sub-wavelength to near-wavelength dimensions of the pyramidal 3D geometry suggest contributions from diffraction and near-field effects. Our theoretical analysis of the light intensity distribution in the similar (but simpler) 2D geometry assuming a perfect conductor screen, ...

  16. Length of Chain in Pyramidal Firms towards Expropriation of Minority Interest

    OpenAIRE

    Irfah Najihah Basir Malan; Norhana Salamudin; Noryati Ahmad

    2015-01-01

    It is documented that there is a large divergence of cash flow rights and control rights in ownership concentrated corporations whereby power lies in the hands of the ultimate controlling shareholder especially for Malaysian pyramidal firms. The divergence of these two rights via length of chain leads to the expropriation of minority shareholders interest. Thus, this study aims to examine the factors influencing the length of chain of Malaysian pyramidal firms implying expropriation of minori...

  17. Computed tomography imaging of the pyramidal lobe of the thyroid gland

    International Nuclear Information System (INIS)

    The pyramidal lobe of the thyroid gland is a normal anatomical variant found frequently in the general population. This structure consists of normal thyroid tissue located in the upper part of the thyroid isthmus, extending upward in the form of a fibrous chord that connects it to the foramen caecum at the bottom of the tongue. This paper reviews thyroid anatomy and embryology, and highlights the main features of the pyramidal lobe, including the anatomy, epidemiology and computed tomography imaging.

  18. Effect of Pyramidal Dome Geometry on the Acoustical Characteristics in A Mosque

    OpenAIRE

    Dg. H. Kassim; A. Putra; M. J. M. NOR; N.S. Muhammad

    2014-01-01

    As an important symbol in Islam, a mosque is built with architectural grandeur. Among the characteristics is its high ceiling and it is usually constructed with a typical spherical dome shape. Some mosques, however, are influenced by the local culture and the dome can be of a different shape, such as pyramidal, as found in mosques in Malacca, Malaysia. This paper presents an assessment of the internal acoustical characteristics of a mosque having a pyramidal dome. The study is conducted by me...

  19. High-Order Optimal Edge Elements for Pyramids, Prisms and Hexahedra

    OpenAIRE

    Bergot, Morgane; Duruflé, Marc

    2013-01-01

    Edge elements are a popular method to solve Maxwell's equations especially in time-harmonic domain. However, when non-affine elements are considered, elements of the Nedelec's first family are not providing an optimal rate of the convergence of the numerical solution toward the solution of the exact problem in H(curl)-norm. We propose new finite element spaces for pyramids, prisms, and hexahedra in order to recover the optimal convergence. In the particular case of pyramids, a comparison with...

  20. Fundamentals of layered nanoparticle covered pyramidal structures formed on nickel during femtosecond laser surface interactions

    Energy Technology Data Exchange (ETDEWEB)

    Zuhlke, Craig A., E-mail: czuhlke11@gmail.com; Anderson, Troy P., E-mail: troy.anderson@unl.edu; Alexander, Dennis R., E-mail: dalexander1@unl.edu

    2013-10-15

    The formation of nanoparticle covered pyramidal structures using femtosecond laser pulses with a fluence near the ablation threshold is reported for the first time. These unique structures form through a combination of preferential ablation of flat regions around the pyramids and redeposition of nanoparticles created during the ablation process. The structures are demonstrated on nickel and stainless steel 316. When produced by rastering Gaussian pulses across the sample, layers of nanoparticles join together by sintering to form unique layered shells.

  1. A pliocene cliff-line around the Giza Pyramids Plateau, Egypt

    OpenAIRE

    Aigner, Thomas

    1982-01-01

    Aigner, T., 1983. A Pliocene cliff-line around the Giza Pyramids Plateau, Egypt. Palaeogeogr., Palaeoclimatol., Palaeoecol., 4 2 : 313—322. Escarpments bordering the Giza Pyramids Plateau represent the cliff-line of a Pliocene transgression up the pre-Nile ("Eonile") Valley. Geomorphologically, a limestone cliff can be distinguished from a slip-block shore associated with a distinct fining-up sequence. Differences in bedrock lithology and in structure (Joint pattern, faults) are morphogen...

  2. Fundamentals of layered nanoparticle covered pyramidal structures formed on nickel during femtosecond laser surface interactions

    International Nuclear Information System (INIS)

    The formation of nanoparticle covered pyramidal structures using femtosecond laser pulses with a fluence near the ablation threshold is reported for the first time. These unique structures form through a combination of preferential ablation of flat regions around the pyramids and redeposition of nanoparticles created during the ablation process. The structures are demonstrated on nickel and stainless steel 316. When produced by rastering Gaussian pulses across the sample, layers of nanoparticles join together by sintering to form unique layered shells.

  3. Intracortical circuits of pyramidal neurons reflect their long-range axonal targets

    OpenAIRE

    Brown, Solange P.; Hestrin, Shaul

    2009-01-01

    Cortical columns generate separate streams of information that are distributed to numerous cortical and subcortical brain regions1. We asked whether local intracortical circuits reflect these different processing streams by testing if the intracortical connectivity among pyramids reflects their long-range axonal targets. We recorded simultaneously from up to four retrogradely labelled pyramids that projected to the superior colliculus, the contralateral striatum or the contralateral cortex to...

  4. Moving Toward the Food Guide Pyramid: Implications for U.S. Agriculture

    OpenAIRE

    Young, C. Edwin; Kantor, Linda Scott

    1999-01-01

    Recent studies show that average diets differ considerably from Food Guide Pyramid recommendations. The gap between current consumption and recommendations is particularly large for caloric sweeteners, fats and oils, fruits, and certain vegetables, notably dark-green leafy and deep-yellow vegetables, and dry beans, peas, and lentils. The change in food consumption needed to meet Food Guide Pyramid serving recommendations will result in adjustments in U.S. agricultural production, trade, nonfo...

  5. Alterations in dendrite and spine morphology of cortical pyramidal neurons in DISC1-binding zinc finger protein (DBZ Knockout mice

    Directory of Open Access Journals (Sweden)

    Tsuyoshi Hattori

    2015-04-01

    Full Text Available Dendrite and dendritic spine formation are crucial for proper brain function. DISC1-binding zinc finger protein (DBZ was first identified as a Disrupted-In-Schizophrenia1 (DISC1 binding partner. DBZ is highly expressed in the cerebral cortex of developing and adult rodents and is involved in neurite formation, cell positioning, and the development of interneurons and oligodendrocytes. The functional roles of DBZ in postnatal brain remain unknown; thus we investigated cortical pyramidal neuron morphology in DBZ knockout (KO mice. Morphological analyses by Golgi staining alone in DBZ KO mice revealed decreased dendritic arborization, increased spine density. A morphological analysis of the spines revealed markedly increased numbers of thin spines. To investigate whole spine structure in detail, electron tomographic analysis using ultra-high voltage electron microscopy combined with Golgi staining was performed. Tomograms and three-dimensional models of spines revealed that the spines of DBZ KO mice exhibited two types of characteristic morphology, filopodia-like spines and abnormal thin-necked spines having an extremely thin spine neck. Moreover, conventional electron microscopy revealed significantly decreased number of postsynaptic densities (PSDs in spines of DBZ KO mice. In conclusion, DBZ deficiency impairs the morphogenesis of dendrites and spines in cortical pyramidal neurons.

  6. Alterations in dendrite and spine morphology of cortical pyramidal neurons in DISC1-binding zinc finger protein (DBZ) knockout mice.

    Science.gov (United States)

    Koyama, Yoshihisa; Hattori, Tsuyoshi; Nishida, Tomoki; Hori, Osamu; Tohyama, Masaya

    2015-01-01

    Dendrite and dendritic spine formation are crucial for proper brain function. DISC1-binding zinc finger protein (DBZ) was first identified as a Disrupted-In-Schizophrenia1 (DISC1) binding partner. DBZ is highly expressed in the cerebral cortex of developing and adult rodents and is involved in neurite formation, cell positioning, and the development of interneurons and oligodendrocytes. The functional roles of DBZ in postnatal brain remain unknown; thus we investigated cortical pyramidal neuron morphology in DBZ knockout (KO) mice. Morphological analyses by Golgi staining alone in DBZ KO mice revealed decreased dendritic arborization, increased spine density. A morphological analysis of the spines revealed markedly increased numbers of thin spines. To investigate whole spine structure in detail, electron tomographic analysis using ultra-high voltage electron microscopy (UHVEM) combined with Golgi staining was performed. Tomograms and three-dimensional models of spines revealed that the spines of DBZ KO mice exhibited two types of characteristic morphology, filopodia-like spines and abnormal thin-necked spines having an extremely thin spine neck. Moreover, conventional electron microscopy revealed significantly decreased number of postsynaptic densities (PSDs) in spines of DBZ KO mice. In conclusion, DBZ deficiency impairs the morphogenesis of dendrites and spines in cortical pyramidal neurons. PMID:25983680

  7. Two-Sided Pyramid Wavefront Sensor in the Direct Phase Mode

    Energy Technology Data Exchange (ETDEWEB)

    Phillion, D; Baker, K

    2006-04-12

    The two-sided pyramid wavefront sensor has been extensively simulated in the direct phase mode using a wave optics code. The two-sided pyramid divides the focal plane so that each half of the core only interferes with the speckles in its half of the focal plane. A relayed image of the pupil plane is formed at the CCD camera for each half. Antipodal speckle pairs are separated so that a pure phase variation causes amplitude variations in the two images. The phase is reconstructed from the difference of the two amplitudes by transforming cosine waves into sine waves using the Hilbert transform. There are also other corrections which have to be applied in Fourier space. The two-sided pyramid wavefront sensor performs extremely well: After two or three iterations, the phase error varies purely in y. The two-sided pyramid pair enables the phase to be completely reconstructed. Its performance has been modeled closed loop with atmospheric turbulence and wind. Both photon noise and read noise were included. The three-sided and four-sided pyramid wavefront sensors have also been studied in direct phase mode. Neither performs nearly as well as does the two-sided pyramid wavefront sensor.

  8. Crystalline silicon solar cells with micro/nano texture

    Science.gov (United States)

    Dimitrov, Dimitre Z.; Du, Chen-Hsun

    2013-02-01

    Crystalline silicon solar cells with two-scale texture consisting of random upright pyramids and surface nanotextured layer directly onto the pyramids are prepared and reflectance properties and I-V characteristics measured. Random pyramids texture is produced by etching in an alkaline solution. On top of the pyramids texture, a nanotexture is developed using an electroless oxidation/etching process. Solar cells with two-scale surface texturization are prepared following the standard screen-printing technology sequence. The micro/nano surface is found to lower considerably the light reflectance of silicon. The short wavelengths spectral response (blue response) improvement is observed in micro/nano textured solar cells compared to standard upright pyramids textured cells. An efficiency of 17.5% is measured for the best micro/nano textured c-Si solar cell. The efficiency improvement is found to be due to the gain in both Jsc and Voc.

  9. Spatial distribution of Pr3+ and F- ions in Ca1-xPrxF2+x luminescent thin films

    International Nuclear Information System (INIS)

    Full text: The 1G4 → 3H5 transition of Pr3+ (4f2) ions, leading to a fluorescence at 1.3 μm is of great interest. It lies within one spectral range for minimum absorption in silica-based optical fibres. Moreover, to achieve further plan optical wave-guides, it must be noticed that CaF2 can be epitaxially grown on silicon substrates and that the solubility limit of PrF3 in CaF2 is very large. Consequently, Ca1-xPrxF2+x solid solutions powders and thin films were elaborated. The aim of this paper is to describe the different phases of the thin film preparation and to give their physico-chemical characterization. We will emphasize the presentation of the spatial distribution of both Pr3+ ions and charge compensating ions which greatly influences the luminescence rate of the rare earth (RE). X-ray diffraction (XRD) and Raman spectroscopy show that in order to obtain solid solution powders, a 1100 deg C, 8 hours heating of high purity CaF2-PrF3 blends under vacuum condition is necessary. Thin films were grown by thermal evaporation of the obtained product. Their composition and the spatial distribution of the different elements were mainly deduced from Rutherford backscattering and particle-induced x-ray emission techniques, using a nuclear microprobe. It is demonstrated that, if the first vapours are collected, the first layers of the films are abnormally rich in praseodymium. To obtain a constant Pr content along the depth of the samples, a pre-evaporation of the initial powders during about one hour is indispensable. In this case, the films are quite pure and homogeneous. At last, from a selective laser excitation technique, the nature of the charge compensating ions and their location from RE3+ substituting ions were described studying the transition between the different Stark sublevels of the 1D2and 3H4 multiplets. It is shown that in Ca1-xPrxF2+x thin films (x ≤ 0.01), aged several weeks in air, Pr3+ ions are compensated by interstitial Fi- ions in nn sites

  10. Enhanced performance of solar cells with optimized surface recombination and efficient photon capturing via anisotropic-etching of black silicon

    Energy Technology Data Exchange (ETDEWEB)

    Chen, H. Y.; Peng, Y., E-mail: gdyuan@semi.ac.cn, E-mail: py@usst.edu.cn; Hong, M.; Zhang, Y. B.; Cai, Bin; Zhu, Y. M. [Shanghai Key Lab of Modern Optical System and Engineering Research Center of Optical Instrument and System, Ministry of Education, University of Shanghai for Science and Technology, Shanghai 200093 (China); Yuan, G. D., E-mail: gdyuan@semi.ac.cn, E-mail: py@usst.edu.cn; Zhang, Y.; Liu, Z. Q.; Wang, J. X.; Li, J. M. [Semiconductor Lighting R and D Center, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China)

    2014-05-12

    We report an enhanced conversion efficiency of femtosecond-laser treated silicon solar cells by surface modification of anisotropic-etching. The etching improves minority carrier lifetime inside modified black silicon area substantially; moreover, after the etching, an inverted pyramids/upright pyramids mixed texture surface is obtained, which shows better photon capturing capability than that of conventional pyramid texture. Combing of these two merits, the reformed solar cells show higher conversion efficiency than that of conventional pyramid textured cells. This work presents a way for fabricating high performance silicon solar cells, which can be easily applied to mass-production.

  11. EPSPs Measured in Proximal Dendritic Spines of Cortical Pyramidal Neurons.

    Science.gov (United States)

    Acker, Corey D; Hoyos, Erika; Loew, Leslie M

    2016-01-01

    EPSPs occur when the neurotransmitter glutamate binds to postsynaptic receptors located on small pleomorphic membrane protrusions called dendritic spines. To transmit the synaptic signal, these potentials must travel through the spine neck and the dendritic tree to reach the soma. Due to their small size, the electrical behavior of spines and their ability to compartmentalize electrical signals has been very difficult to assess experimentally. In this study, we developed a method to perform simultaneous two-photon voltage-sensitive dye recording with two-photon glutamate uncaging in order to measure the characteristics (amplitude and duration) of uncaging-evoked EPSPs in single spines on the basal dendrites of L5 pyramidal neurons in acute brain slices from CD1 control mice. We were able to record uncaging-evoked spine potentials that resembled miniature EPSPs at the soma from a wide range of spine morphologies. In proximal spines, these potentials averaged 13.0 mV (range, 6.5-30.8 mV; N = 20) for an average somatic EPSP of 0.59 mV, whereas the mean attenuation ratio (spine/soma) was found to be 25.3. Durations of spine EPSP waveforms were found to be 11.7 ms on average. Modeling studies demonstrate the important role that spine neck resistance (R neck) plays in spine EPSP amplitudes. Simulations used to estimate R neck by fits to voltage-sensitive dye measurements produced a mean of 179 MΩ (range, 23-420 MΩ; N = 19). Independent measurements based on fluorescence recovery after photobleaching of a cytosolic dye from spines of the same population of neurons produced a mean R neck estimate of 204 MΩ (range, 52-521 MΩ; N = 34). PMID:27257618

  12. Hypertension impairs hippocampus-related adult neurogenesis, CA1 neuron dendritic arborization and long-term memory.

    Science.gov (United States)

    Shih, Y-H; Tsai, S-F; Huang, S-H; Chiang, Y-T; Hughes, M W; Wu, S-Y; Lee, C-W; Yang, T-T; Kuo, Y-M

    2016-05-13

    Hypertension is associated with neurodegenerative diseases and cognitive impairment. Several studies using spontaneous hypertensive rats to study the effect of hypertension on memory performance and adult hippocampal neurogenesis have reached inconsistent conclusions. The contradictory findings may be related to the genetic variability of spontaneous hypertensive rats due to the conventional breeding practices. The objective of this study is to examine the effect of hypertension on hippocampal structure and function in isogenic mice. Hypertension was induced by the '2 kidneys, 1 clip' method (2K1C) which constricted one of the two renal arteries. The blood pressures of 2K1C mice were higher than the sham group on post-operation day 7 and remained high up to day 28. Mice with 2K1C-induced hypertension had impaired long-term, but not short-term, memory. Dendritic complexity of CA1 neurons and hippocampal neurogenesis were reduced by 2K1C-induced hypertension on post-operation day 28. Furthermore, 2K1C decreased the levels of hippocampal brain-derived neurotrophic factor, while blood vessel density and activation status of astrocytes and microglia were not affected. In conclusion, hypertension impairs hippocampus-associated long-term memory, dendritic arborization and neurogenesis, which may be caused by down-regulation of brain-derived neurotrophic factor signaling pathways. PMID:26921651

  13. Segregation of antiferromagnetism and high-temperature superconductivity in Ca1-xLaxFe2As2

    Science.gov (United States)

    Saha, Shanta R.; Drye, T.; Goh, S. K.; Klintberg, L. E.; Silver, J. M.; Grosche, F. M.; Sutherland, M.; Munsie, T. J. S.; Luke, G. M.; Pratt, D. K.; Lynn, J. W.; Paglione, J.

    2014-04-01

    We report the effect of applied pressures on magnetic and superconducting order in single crystals of the aliovalent La-doped iron pnictide material Ca1-xLaxFe2As2. Using electrical transport, elastic neutron scattering, and resonant tunnel diode oscillator measurements on samples under both quasihydrostatic and hydrostatic pressure conditions, we report a series of phase diagrams spanning the range of substitution concentrations for both antiferromagnetic and superconducting ground states that include pressure-tuning through the antiferromagnetic (AFM) superconducting critical point. Our results indicate that the observed superconducting phase with a maximum transition temperature of Tc=47 K is intrinsic to these materials, appearing only upon suppression of magnetic order by pressure-tuning through the AFM critical point. Thus, the superconducting phase appears to exist exclusively in juxtaposition to the antiferromagnetic phase in a manner similar to the oxygen- and fluorine-based iron-pnictide superconductors with the highest transition temperatures reported to date. Unlike the lower-Tc systems, in which superconductivity and magnetism usually coexist, the tendency for the highest-Tc systems to show noncoexistence provides an important insight into the distinct transition temperature limits in different members of the iron-based superconductor family.

  14. Long-term fluoxetine treatment induces input-specific LTP and LTD impairment and structural plasticity in the CA1 hippocampal subfield.

    Directory of Open Access Journals (Sweden)

    Francisco J Rubio

    2013-05-01

    Full Text Available Antidepressant drugs are usually administered for long time for the treatment of major depressive disorder. However, they are also prescribed in several additional psychiatric conditions as well as during long term maintenance treatments. Antidepressants induce adaptive changes in several forebrain structures which include modifications at glutamatergic synapses. We recently found that repetitive administration of the selective serotonin reuptake inhibitor fluoxetine to naϊve adult male rats induced an increase of mature, mushroom-type dendritic spines in several forebrain regions. This was associated with an increase of GluA2-containing α-amino-3-hydroxy-5-methylisoxazole-4-propionate receptors (AMPA-Rs in telencephalic postsynaptic densities. To unravel the functional significance of such a synaptic re-arrangement, we focused on glutamate neurotransmission in the hippocampus. We evaluated the effect of four weeks of treatment with 0.7 mg/kg of fluoxetine on long-term potentiation (LTP and long-term depression (LTD in the Schaffer collateral-CA1 synapses and the perforant path-CA1 synapses. Recordings in hippocampal slices revealed profound deficits in LTP and LTD at Schaffer collateral-CA1 synapses associated to increased spine density and enhanced presence of mushroom-type spines, as revealed by Golgi staining. However, the same treatment had neither an effect on spine morphology, nor on LTP and LTD at perforant path-CA1 synapses. Cobalt staining experiments revealed decreased AMPA-R Ca2+ permeability in the stratum radiatum together with increased GluA2-containing, Ca2+-impermeable AMPA-Rs. Therefore, 4 weeks of fluoxetine treatment promoted structural and functional adaptations in CA1 neurons in a pathway-specific manner that were selectively associated with impairment of activity-dependent plasticity at Schaffer collateral-CA1 synapses.

  15. Size effect in contact compression of nano- and microscale pyramid structures

    International Nuclear Information System (INIS)

    An electrochemical etching approach was developed to fabricate self-similar nano- and microscale pyramid structures on single-crystal gold (1 0 0) surfaces. Using their unique self-similar characteristics, pyramids of (1 1 4) facets were compressed to study the length scale effects in the contact pressure and plastic deformation. At first, many pyramids were compressed simultaneously with a flat mica sheet to measure the ridge angle changes of the deformed pyramids with respect to the sizes of the flattened area. The ridge angle changes were scattered between approximately 2o and 13o for compression displacements of 50-350 nm, in contrast to the perfect plasticity prediction of -4.7o. Then, individual pyramids isolated with a focused ion beam were compressed with a flat tip nanoindenter for displacements of approximately 10-100 nm to obtain the relationship between the contact pressure and the compression depth. The plastic deformation-adjusted contact pressure evaluated by taking into account the initial 6-14 nm roundness offset of the pyramids is characterized by an initial increase up to approximately 2.5 GPa for a shallow compression depth within 10 nm followed by a gradual decay to approximately 450 MPa at a compression depth of 100 nm. This pressure seems to be still decaying towards an asymptotic value predicted by a continuum limit analysis. Given the size and self-similar nature of the pyramids, various mechanisms could possibly contribute to the observed scale dependence. The current study provides valuable experimental evidence for size-dependent material behavior at small length scales

  16. The contrasting effects of dendrotoxins and other potassium channel blockers in the CA1 and dentate gyrus regions of rat hippocampal slices

    OpenAIRE

    Southan, A P; Owen, D. G.

    1997-01-01

    The effects of potassium channel blocking compounds on synaptic transmission in the CA1 and dentate gyrus regions of the rat hippocampus were examined by means of simultaneous field potential recording techniques in brain slices.4-Aminopyridine (4-AP) enhanced the excitatory postsynaptic potential (e.p.s.p.) and induced multiple population spike responses in both regions. EC50 values were 6.7 μM in the CA1 (n=5) and 161.7 μM (n=5) in the dentate gyrus.Tetraethylammonium (TEA) increased the am...

  17. N-methyl-D-aspartate receptor activation increases cAMP levels and voltage-gated Ca2+ channel activity in area CA1 of hippocampus.

    OpenAIRE

    Chetkovich, D.M.; Gray., R; Johnston, D.; Sweatt, J D

    1991-01-01

    Tetanic stimulation of the Schaffer collateral inputs into area CA1 of the hippocampus causes N-methyl-D-aspartate (NMDA) receptor activation, an effect that contributes to the induction of long-term potentiation (LTP) in this region. The present studies demonstrate that LTP-inducing tetanic stimulation in rat hippocampal area CA1 elicited increased levels of cAMP. The elevation of cAMP was blocked by the NMDA receptor antagonist DL-2-amino-5-phosphonovaleric acid (APV). Bath application of N...

  18. Evaluation of the pyramidal tract in patients with brain tumor in terms of diffusion anisotropy, apparent diffusion coefficient and eigenvalues

    International Nuclear Information System (INIS)

    Diffusion anisotropy index, diffusion trace and eigenvalues of the pyramidal tracts were measured in 19 patients with supratentorial brain tumor using diffusion tensor MR imaging. These indices reflected condition of pyramidal tract, being compressed and/or being T2-high. Estimation of eigenvalues, in addition to diffusion anisotropy and the trace, should provide more detailed information about the pyramidal tract in brain tumor cases. (author)

  19. What's a Pregnant Woman to Eat? A Review of Current USDA Dietary Guidelines and MyPyramid

    OpenAIRE

    Fowles, Eileen R.

    2006-01-01

    The purpose of this article is to clarify the nutritional recommendations for pregnant women in light of the new Food Guide Pyramid, known as “MyPyramid,” along with the Dietary Guidelines for Americans 2005 and recommendations by the Institute of Medicine. The differences between the Food Guide Pyramid (introduced in 1992) and the more recent, color-coded MyPyramid (introduced in 2005) are discussed. A list of nutritional recommendations for pregnant women is presented, which may serve as a ...

  20. Revisiting pyramid compression to quantify flexoelectricity: A three-dimensional simulation study

    Science.gov (United States)

    Abdollahi, Amir; Millán, Daniel; Peco, Christian; Arroyo, Marino; Arias, Irene

    2015-03-01

    Flexoelectricity is a universal property of all dielectrics by which they generate a voltage in response to an inhomogeneous deformation. One of the controversial issues in this field concerns the magnitude of flexoelectric coefficients measured experimentally, which greatly exceed theoretical estimates. Furthermore, there is a broad scatter amongst experimental measurements. The truncated pyramid compression method is one of the common setups to quantify flexoelectricity, the interpretation of which relies on simplified analytical equations to estimate strain gradients. However, the deformation fields in three-dimensional pyramid configurations are highly complex, particularly around its edges. In the present work, using three-dimensional self-consistent simulations of flexoelectricity, we show that the simplified analytical estimations of strain gradients in compressed pyramids significantly overestimate flexoelectric coefficients, thus providing a possible explanation to reconcile different estimates. In fact, the interpretation of pyramid compression experiments is highly nontrivial. We systematically characterize the magnitude of this overestimation, of over one order of magnitude, as a function of the truncated pyramid configuration. These results are important to properly characterize flexoelectricity, and provide design guidelines for effective electromechanical transducers exploiting flexoelectricity.