bluuebunny/crossref_metadata_2025 huggingface dataset:
Interpretation of multicomponent seismic data across Wister geothermal field, Imperial Valley, California
Authors: Wei Shuijian , DeAngelo Michael V. , Hardage Bob A.
Published: April 2014

Multicomponent seismic technology has been implemented across Wister geothermal field in southern California to evaluate the potential for further development of geothermal resources. The seismic survey was positioned atop the San Andreas fault system that extends southward from the Salton Sea. An interpretation of Wister Field geology was made using both P-P and P-SV seismic data. Two formation horizons, Canebrake/Olla/Diablo and Deguynos, were interpreted. Seismic time-structure maps were generated for each horizon. The objective of the study was to determine whether productive geothermal resources could be detected and mapped more reliably with multicomponent seismic data than with single-component P-P data. Complex faults associated with the regional San Andreas Fault system were interpreted across the [Formula: see text] 3D image space. The structural maps created are thought to be some of the most accurate depictions of subsurface structure publicly available in this area of the Imperial Valley. Particular attention was given to documenting faults that cut across deep strata. Both P-P and P-SV seismic showed evidence of such deep faults. Rock properties were analyzed from well logs. Log data showed that clastic rocks at this site exhibited measurable differences in [Formula: see text] velocity ratios for different rock types. Specifically, sand-prone intervals were associated with relatively low [Formula: see text] velocity ratios, and shale-dominated intervals had higher [Formula: see text] ratios. Using this rock physics behavior, [Formula: see text] values derived from seismic traveltime thicknesses were useful for recognizing lithological distributions and identifying favorable reservoir facies. Seismic data across Wister Field, like seismic data across many geothermal fields, have a low signal-to-noise character. We demonstrate that a unified and integrated interpretation of P and S data, even when seismic data quality is not as good as interpreters wish, can still yield valuable information for resource exploitation.
3D Alford rotation analysis for the Diamond M Field, Midland Basin, Texas
Authors: Davogustto Cataldo Oswaldo E. , Kwiatkowski Timothy J. , Marfurt Kurt J. , Roche Steven L. , Thomas James W.
Published: April 2014

The 2C by 2C S-wave survey generated significant excitement in the mid-1980s, but then it fell out of favor when S-wave splitting initially attributed to fractures was also found to be associated with an anisotropic stress regime. In general, 2C by 2C data require more expensive acquisition and more processing effort to obtain images comparable to 1C “compressional wave” data acquired with vertical component sources and receivers. Because S-waves are insensitive to fluids, and hence the water table, the effective S-wave weathering zone is greater than that for compressional waves, making statics more difficult. S-wave splitting due to anisotropy complicates residual statics and velocity analysis as well as the final image. S-wave frequencies and S-wave moveout are closer to those of contaminating ground roll than compressional waves. Since Alford’s introduction of S-wave rotation from survey coordinates to the principal axes in 1986, geoscientist and engineers retain their interest in fractures but are also keenly interested in the direction and magnitude of maximum horizontal stress. Simultaneous sweep and improved recording technology have reduced the acquisition cost to approximate that of 1C data. Alford’s work was applied to 2C by 2C poststack data. We extended the Alford rotation to prestack data using a modern high-fold 2C by 2C survey acquired over a fractured carbonate reservoir in the Diamond M Field, Texas. Through careful processing, the resulting images were comparable and in many places superior to that of the contemporaneously acquired 1C data. More importantly, we found a good correlation between our derived fracture azimuth map and the fracture azimuth log data from wells present in the field.
Emerging Multifunctional Roles of Claudin Tight Junction Proteins in Bone
Authors: Alshbool Fatima. Z. , Mohan Subburaman
Published: April 2014

The imbalance between bone formation and resorption during bone remodeling has been documented to be a major factor in the pathogenesis of osteoporosis. Recent evidence suggests a significant role for the tight junction proteins, Claudins (Cldns), in the regulation of bone remodeling processes. In terms of function, whereas Cldns act “canonically” as key determinants of paracellular permeability, there is considerable recent evidence to suggest that Cldns also participate in cell signaling, ie, a “noncanonical function”. To this end, Cldns have been shown to regulate cell proliferation, differentiation, and gene expression in a variety of cell types. The present review will discuss Cldns’ structure, their expression profile, regulation of expression, and their canonical and non- canonical functions in general with special emphasis on bone cells. In order to shed light on the noncanonical functions of Cldns in bone, we will highlight the role of Cldn-18 in regulating bone resorption and osteoclast differentiation. Collectively, we hope to provide a framework for guiding future research on understanding how Cldns modulate osteoblast and osteoclast function and overall bone homeostasis. Such studies should provide valuable insights into the pathogenesis of osteoporosis, and may highlight Cldns as novel targets for the diagnosis and therapeutic management of osteoporosis.
Quality Assessment of Unmanned Aerial Vehicle (UAV) Based Visual Inspection of Structures
Authors: Morgenthal G. , Hallermann N.
Published: April 2014

This paper discusses the application of Unmanned Aerial Vehicles (UAV) for visual inspection and damage detection on civil structures. The quality of photos and videos taken by using such airborne vehicles is strongly influenced by numerous parameters such as lighting conditions, distance to the object and vehicle motion induced by environmental effects. Whilst such devices feature highly sophisticated sensors and control algorithms, specifically the effects of fluctuating wind speeds and directions affect the vehicle motion. The nature of vehicle movements during photo and video acquisition in turn affect the quality of the data and hence the degree to which damages can be identified. This paper discusses the properties of such flight systems, the factors influencing their movements and the resulting photo quality. Based on the processed data logged by the high precision sensors on the UAV the influences are studied and a method is shown by which the damage assessment quality may be quantified.
A Global Artificial Fish Swarm Algorithm for Structural Damage Detection
Authors: Yu Ling , Li Cheng
Published: April 2014

Structural damage detection (SDD) is an important but still challenging task in the structural health monitoring (SHM) field. Many methodologies have been developed and broad application prospect are expected. However, there are still some difficulties when they are applied to the real structures. In this study, a novel global artificial fish swarm algorithm (GAFSA) is proposed for exploring a new solution to the SDD problem in the SHM field. Firstly, the basic theory of the GAFSA is introduced. The fish swarm behaviours inside water are simulated by the following four steps: random, preying, swarming and following behaviours, respectively. The artificial fish parameters are defined, the implementing procedure of GAFSA is expressed, and the computing performance of GAFSA is evaluated and compared with the basic artificial fish swarm algorithm by three test functions. Secondly, the SDD problem is modelled as a constrained optimization problem in mathematics, an objective function on optimization problem is defined, and the model updating-based SDD is hopefully solved by the proposed GAFSA, which is based on swarm intelligence and uses a population (or swarm) of fish to identify promising regions looking for a global solution. Some numerical simulations on single and multiple damage cases of both an ASCE 4-storey benchmark frame structure and a 2-storey rigid frame have been conducted for assessing the effectiveness and robustness of the proposed GAFSA. Finally, a laboratory experimental study on damage detection of a 3-storey building model with four damage patterns was performed. The illustrated results show that the proposed GAFSA can not only locate the structural damage but also quantify the severity of damage with a good noise immunity.
Progressive Collapse Mechanisms of Steel Frames Exposed to Fire
Authors: Jiang Jian , Li Guo-Qiang , Usmani Asif
Published: April 2014

OpenSees is an open-source object-oriented software framework developed at UC Berekeley. The OpenSees framework has been recently extended to deal with structural behavior under fire conditions. This paper summaries the key work done for this extension and focuses on the application of the developed OpenSees to study the fire-induced progressive collapse mechanisms of steel structures. The implicit dynamic analysis method (Newmark method) is applied and the influences of the load ratios, beam sizes and fire scenarios on the collapse behavior of frames are investigated. Single-compartment fire scenarios in the central bay and edge bay are considered, respectively. A total of four collapse mechanisms of steel frames are proposed by varying the three influencing factors. Most of the collapse of steel frames is triggered by the buckling of the heated columns. The thermal expansion of heated beams at early heating stage and their catenary action at high temperature have great influences on the collapse mechanisms. The most common collapse mode of steel frames are in the form of lateral drift of frames above the heated floor together with downward collapse of frames along the heated bay. As the load increases, the collapse behavior of structures is dominated by a downward collapse of the whole frame with little sign of the upper frame drift. The collapse modes of steel frames with strong and weak beams are column failure mechanism and beam failure mechanism, respectively. The former mechanism is due to the buckling of the columns below the heated floor represented by a global collapse of the frame and the latter is initiated by the premature development of plastic hinges at the ends of beams denoted by an obvious lateral drift of the heated floor. Generally, the edge bay fire is more prone to induce the collapse of structures than the central bay fire. It is found that the most dangerous situation is the frame subjected to high load ratios exposed to a central bay fire where its progressive collapse may occur as early as 250°C.
Incremental Dynamic Analysis of Highway Bridges with Novel Shape Memory Alloy Isolators
Authors: Zhu Songye , Qiu Can-Xing
Published: April 2014

Base isolators are commonly used to protect highway bridges from severe seismic damage. A novel self-centering isolator based on superelastic shape memory alloy (SMA) has been proposed to be installed between the piers and decks of highway bridges. This paper systematically evaluates the seismic performance of SMA isolators via the incremental dynamic analysis (IDA) of a prototype highway bridge with SMA isolators. The multi-span reinforced concrete highway bridge and the corresponding SMA isolators are designed according to an ad hoc displacement-based design (DBD) approach. The seismic analyses are conducted under different seismic intensity levels using the computation program DRAIN2DX. IDA results indicate that the SMA isolators can effectively protect the superstructure of the highway bridge and minimize the post-earthquake residual deformation. The properly designed highway bridges with SMA isolators are subjected to limited damage under frequent and design basis earthquakes.
Performance Based Rapid Seismic Assessment Method (PERA) for Reinforced Concrete Frame Buildings
Authors: Ilki A. , Comert M. , Demir C. , Orakcal K. , Ulugtekin D. , Tapan M. , Kumbasar N.
Published: April 2014

Recent destructive earthquakes have shown that many existing buildings, particularly in developing countries, are not safe against seismic actions. Since code-based seismic safety evaluation methods generally require detailed and complex structural analysis, the necessity for simplified, yet sufficiently accurate evaluation methods emerges for reducing cost and duration of assessment procedures. In this study, a performance based rapid seismic safety assessment method (PERA) is proposed for reinforced concrete buildings. The overall structural performance is determined based on the demand/capacity ratios of individual columns, as well as their failure modes (brittle/ductile), confinement characteristics, and levels of axial and shear stresses. The lateral drift of the critical story, calculated through a simplified approach, is also taken into account during determination of the global structural performance. The predictions of this method are compared with the results of conventional detailed seismic safety assessment analyses carried out for 672 different cases representing typical reinforced concrete frame buildings in Turkey. Good agreement is obtained between the predictions of the proposed algorithm and code-based structural performance assessment procedures. Finally, predictions of the proposed approach are compared with actual damages observed in 21 existing buildings in Turkey after destructive earthquakes that have occurred during the last two decades. These comparisons also point to an acceptable level of accuracy and sufficient conservatism for the methodology proposed.
Stress and Deformation in Thin Plate on Which Expanded Jet Impinges
Authors: Inamura Eijiro , Endo Masaki , Iwamoto Junjiro
Published: April 2014

This paper discusses the stress and the deformation of a thin circular plate, loaded by an impingement of an underexpanded jet. When the jet impinges on an object the self-excited oscillation of the jet occurs and the object is cooled. If the object is an elastic thin plate, it is deformed and made to vibrate. In order to clarify the influence of self-excited oscillation on the deformation of the plate, pressure, temperature, strain and the deflection on the plate are experimentally measured at the different nozzle-plate distances. Using the experimental results such as the pressure and temperature, the deflection of the plate is analyzed by the finite element method. The analytical results are compared with those obtained by experiment.
On the Discrete and Continuous Spectrum of Acoustic-Vortical Waves
Authors: Campos L. M. B. C. , Serrão P. G. T. A.
Published: April 2014

A wave propagating in a non-uniform flow can have a critical layer where it is absorbed, amplified, reflected, or converted to another mode, possibly exchanging energy with the mean flow. Two examples are the propagation of: (i) fan noise in the shear flow in the air inlet of a jet engine; (ii) turbine noise in the swirling flow in the jet exhaust. Both situations (i) and (ii) are included by considering wave propagation in an axisymmetric isentropic non-homentopic mean flow allowing for the simultaneous existence of shear, swirl, temperature and density gradients. This corresponds to coupled acoustic-vortical modes that have both continuous and discrete spectra. It is shown that a critical layer exists where the Doppler shifted frequency vanishes. A stability condition is obtained for the continuous spectrum for all frequencies, axial and azimuthal wavenumbers generalizing previous results from the homentropic to the isentropic non-isentropic case. The wave fields are calculated and plotted for a case of non-rigid body rotation, namely angular velocity of swirl proportional to the radius; this demonstrates the mode conversion between acoustic and vortical waves across the critical layer where the waves are absorbed because the pressure spectrum vanishes.
Computational Design Research in Architecture: The Legacy of the Hochschule für Gestaltung, Ulm
Authors: Neves Isabel Clara , Rocha João , Duarte José Pinto
Published: April 2014

The use of computational processes in architecture is a widespread practice which draws on a set of theories of computer science developed in the 60s and 70s. With the advent of computers, many of these methodologies were developed in research centres in the USA and the UK. Focussing on this period, this paper investigates the importance of the German Hochschule fur Gestaltung, Ulm (HfG) design school in the early stages of computation in design and architecture. Even though there were no computers in the school, it may be argued that its innovative pedagogy and distinguished faculty members launched analogical computational design methods that can be seen as the basis for further computational approaches in architecture. The paper draws on archive material, as well as at an original interview with Tomas Maldonado, to propose that the remarkable work pursued by Tomas Maldonado (the educational project), Max Bense (information aesthetics) and Horst Rittel (scientific methods) was fundamental in establishing HfG Ulm as the forerunner of computation in architecture.
No Fear of Ridicule – Deploying Plaything Technology for Credible Representations of Urban Landscape
Authors: Rekittke Joerg , Ninsalam Yazid , Paar Philip
Published: April 2014

As technology affine urban landscape architects, working in Asian mega cities, we conduct research on urbanity beyond prime premises and nice neighbourhoods with maximum tourist potential. We roam through crowded and super narrow, widely informal city layouts, where we apply our digital fieldwork equipment and conduct design work. In these places we test low cost cameras and camera drones, tools that had been developed as documentation equipment for outdoor sportspersons respectively playthings for all the world. Technically limited, if not insufficient and physically labile, these basic tools help us to experiment in the field without problematic loss risks and without scaring people on site. In this paper, we describe a method of on-site data and image gathering, which allows the processing of 3D models of labyrinthine informal city spaces. The result of our study is a three-dimensional puzzle of sufficient precision, making a widely inaccessible and undocumented piece of city terrain visible, understandable and designable.
Quadrilateral Patterns for Rigid Folding Structures
Authors: Stavric Milena , Wiltsche Albert
Published: April 2014

In this paper we will do investigations on spatial quadrilateral meshes developed from folding patterns. The simplicity of manual production in combination with the geometrical complexity of paper folding shall lead to an inspiration for designing architectural structures. We propose geometrical methods for designing these quadrilateral structures which follow in their shape geometrical surfaces. Our methods use folding patterns where only four folding lines meet in one node and every quadrangular part stays flat. This enables simpler solutions for architectural realization in a big scale especially for join connections and assembling of the whole spatial and structural system. In order to understand and handle the complexity of paper folding we use CAD tools to model the structures where the entire folding element is reconstructed and its geometric characteristics are controlled. This kind of control reflects on scale models. Models are then adjusted, examined and built to reach certain further geometric conclusions that are once more tested in CAD software.
Evolutionary Optimisation of Semi-Transparent Building Integrated Photovoltaic Facades
Authors: Choo Thian-Siong , Janssen Patrick
Published: April 2014

The optimisation of semi-transparent building integrated photovoltaic facades can be challenging when attempting to find an overall balance performance between conflicting performance criteria. This paper presents a three-phase design optimisation method that maximises overall electricity savings generated by these types of facades by simulating the combined impact of electricity generation, cooling load, and daylight autonomy. Two demonstrations are performed, with the difference being that the second demonstration uses an enhanced model for calculating daylight savings that takes into account the use of blinds to counteract glare. For both demonstrations, the three-phase optimisation method significantly reduces optimisation run times. Comparing the design variants evolved by the two demonstrations, the use of the enhanced daylight savings model results in a total electricity savings that is more accurate but in terms of visual differentiation, the difference between the optimized design variants is relatively small.
An adaptable pentaloop defines a robust neomycin-B RNA aptamer with conditional ligand-bound structures
Authors: Ilgu Muslum , Fulton D. Bruce , Yennamalli Ragothaman M. , Lamm Monica H. , Sen Taner Z. , Nilsen-Hamilton Marit
Published: April 2014

Aptamers can be highly specific for their targets, which implies precise molecular recognition between aptamer and target. However, as small polymers, their structures are more subject to environmental conditions than the more constrained longer RNAs such as those that constitute the ribosome. To understand the balance between structural and environmental factors in establishing ligand specificity of aptamers, we examined the RNA aptamer (NEO1A) previously reported as specific for neomycin-B. We show that NEO1A can recognize other aminoglycosides with similar affinities as for neomycin-B and its aminoglycoside specificity is strongly influenced by ionic strength and buffer composition. NMR and 2-aminopurine (2AP) fluorescence studies of the aptamer identified a flexible pentaloop and a stable binding pocket. Consistent with a well-structured binding pocket, docking analysis results correlated with experimental measures of the binding energy for most ligands. Steady state fluorescence studies of 2AP-substituted aptamers confirmed that A16 moves to a more solvent accessible position upon ligand binding while A14 moves to a less solvent accessible position, which is most likely a base stack. Analysis of binding affinities of NEO1A sequence variants showed that the base in position 16 interacts differently with each ligand and the interaction is a function of the buffer constituents. Our results show that the pentaloop provides NEO1A with the ability to adapt to external influences on its structure, with the critical base at position 16 adjusting to incorporate each ligand into a stable pocket by hydrophobic interactions and/or hydrogen bonds depending on the ligand and the ionic environment.
Learning to Optimize via Posterior Sampling
Authors: Russo Daniel , Van Roy Benjamin
Published: April 2014

This paper considers the use of a simple posterior sampling algorithm to balance between exploration and exploitation when learning to optimize actions such as in multiarmed bandit problems. The algorithm, also known as Thompson Sampling and as probability matching, offers significant advantages over the popular upper confidence bound (UCB) approach, and can be applied to problems with finite or infinite action spaces and complicated relationships among action rewards. We make two theoretical contributions. The first establishes a connection between posterior sampling and UCB algorithms. This result lets us convert regret bounds developed for UCB algorithms into Bayesian regret bounds for posterior sampling. Our second theoretical contribution is a Bayesian regret bound for posterior sampling that applies broadly and can be specialized to many model classes. This bound depends on a new notion we refer to as the eluder dimension, which measures the degree of dependence among action rewards. Compared to UCB algorithm Bayesian regret bounds for specific model classes, our general bound matches the best available for linear models and is stronger than the best available for generalized linear models. Further, our analysis provides insight into performance advantages of posterior sampling, which are highlighted through simulation results that demonstrate performance surpassing recently proposed UCB algorithms.
Evaluation of Alveolar Bone Density at Furcation Sites Using Computer Tomography in Patients with Horizontal Bone Loss
Authors: Dumitrescu Alexandrina L. , Zetu L. , Teslaru S. , Haba D.
Published: April 2014

Objectives: The aim of the current study was to evaluate quantitatively bone density in the maxillary and mandibular interradicular sites and to establish his determinants as assessed on computer tomography images. 
Methods: Sections of 0.5 mm thickness horizontal CT sections were selected to measure bone density of the interradicular and interdentally septum in CTs from 29 individuals (17 females, mean age 40.44 years). 
Results: There were statistically significant differences of mean value and of bone density at specific bone depth levels in the furcation area according to age, gender, tooth type and between the maxilla and mandible (P < 0.05). The multiple linear regression analyses showed, for both mean furcation alveolar bone density value as well as particular values at different bone level as dependent variable, a strong association with gender, distance from the furcation roof to the alveolar bone septum, presence of restorative treatment of caries, presence of endodontic treatment and mean alveolar bone density of the mesial and distal alveolar septum (P < 0.0001). 
Conclusions: Using the CT in periodontology has demonstrated to be a valid support to diagnose the changes in the alveolar bone, to monitor the treatment results with a higher precision and to point out possible error sources.
Activation of Dopaminergic D2/D3 Receptors Modulates Dorsoventral Connectivity in the Hippocampus and Reverses the Impairment of Working Memory after Nerve Injury
Authors: Cardoso-Cruz Helder , Dourado Margarida , Monteiro Clara , Matos Mariana R. , Galhardo Vasco
Published: April 2014

Dopamine plays an important role in several forms of synaptic plasticity in the hippocampus, a crucial brain structure for working memory (WM) functioning. In this study, we evaluated whether the working-memory impairment characteristic of animal models of chronic pain is dependent on hippocampal dopaminergic signaling. To address this issue, we implanted multichannel arrays of electrodes in the dorsal and ventral hippocampal CA1 region of rats and recorded the neuronal activity during a food-reinforced spatial WM task of trajectory alternation. Within-subject behavioral performance and patterns of dorsoventral neuronal activity were assessed before and after the onset of persistent neuropathic pain using the Spared Nerve Injury (SNI) model of neuropathic pain. Our results show that the peripheral nerve lesion caused a disruption in WM and in hippocampus spike activity and that this disruption was reversed by the systemic administration of the dopamine D2/D3 receptor agonist quinpirole (0.05 mg/kg). In SNI animals, the administration of quinpirole restored both the performance-related and the task-related spike activity to the normal range characteristic of naive animals, whereas quinpirole in sham animals caused the opposite effect. Quinpirole also reversed the abnormally low levels of hippocampus dorsoventral connectivity and phase coherence. Together with our finding of changes in gene expression of dopamine receptors and modulators after the onset of the nerve injury model, these results suggest that disruption of the dopaminergic balance in the hippocampus may be crucial for the clinical neurological and cognitive deficits observed in patients with painful syndromes.
LMTK3 Deficiency Causes Pronounced Locomotor Hyperactivity and Impairs Endocytic Trafficking
Authors: Inoue Takeshi , Hoshina Naosuke , Nakazawa Takanobu , Kiyama Yuji , Kobayashi Shizuka , Abe Takaya , Yamamoto Toshifumi , Manabe Toshiya , Yamamoto Tadashi
Published: April 2014

LMTK3 belongs to the LMTK family of protein kinases that are predominantly expressed in the brain. Physiological functions of LMTK3 and other members of the LMTK family in the CNS remain unknown. In this study, we performed a battery of behavioral analyses usingLmtk3−/−mice and showed that these mice exhibit abnormal behaviors, including pronounced locomotor hyperactivity, reduced anxiety behavior, and decreased depression-like behavior. Concurrently, the dopamine metabolite levels and dopamine turnover rate are increased in the striata ofLmtk3−/−mice compared with wild-type controls. In addition, using cultured primary neurons fromLmtk3−/−mice, we found that LMTK3 is involved in the endocytic trafficking ofN-methyl-d-aspartate receptors, a type of ionotropic glutamate receptor. Altered membrane traffic of the receptor inLmtk3−/−neurons may underlie behavioral abnormalities in the mutant animals. Together, our data suggest that LMTK3 plays an important role in regulating locomotor behavior in mice.
Mice with Compromised 5-HTT Function Lack Phosphotyrosine-Mediated Inhibitory Control over Prefrontal 5-HT Responses
Authors: Goodfellow Nathalie M. , Sargin Derya , Ansorge Mark S. , Gingrich Jay A. , Lambe Evelyn K.
Published: April 2014

The activity of the prefrontal cortex is essential for normal emotional processing and is strongly modulated by serotonin (5-HT). Yet, little is known about the regulatory mechanisms that control the activity of the prefrontal 5-HT receptors. Here, we found and characterized a deregulation of prefrontal 5-HT receptor electrophysiological signaling in mouse models of disrupted serotonin transporter (5-HTT) function, a risk factor for emotional and cognitive disturbances. We identified a novel tyrosine kinase-dependent mechanism that regulates 5-HT-mediated inhibition of prefrontal pyramidal neurons. We report that mice with compromised 5-HTT, resulting from either genetic deletion or brief treatment with selective serotonin reuptake inhibitors during development, have amplified 5-HT1Areceptor-mediated currents in adulthood. These greater inhibitory effects of 5-HT are accompanied by enhanced downstream coupling to Kir3 channels. Notably, in normal wild-type mice, we found that these larger 5-HT1Aresponses can be mimicked through inhibition of Src family tyrosine kinases. By comparison, in our 5-HTT mouse models, the larger 5-HT1Aresponses were rapidly reduced through inhibition of tyrosine phosphatases. Our findings implicate tyrosine phosphorylation in regulating the electrophysiological effects of prefrontal 5-HT1Areceptors with implications for neuropsychiatric diseases associated with emotional dysfunction, such as anxiety and depressive disorders.
In VivoRegulation of NGF-Mediated Functions by Nedd4-2 Ubiquitination of TrkA
Authors: Yu Tao , Calvo Laura , Anta Begoña , López-Benito Saray , López-Bellido Roger , Vicente-García Cristina , Tessarollo Lino , Rodriguez Raquel E. , Arévalo Juan C.
Published: April 2014

Trk neurotrophin receptor ubiquitination in response to ligand activation regulates signaling, trafficking, and degradation of the receptors. However, thein vivoconsequences of Trk ubiquitination remain to be addressed. We have developed a mouse model with a mutation in the TrkA neurotrophin receptor (P782S) that results in reduced ubiquitination due to a lack of binding to the E3 ubiquitin ligase, Nedd4-2.In vivoanalyses of TrkAP782S indicate that defective ubiquitination of the TrkA mutant results in an altered trafficking and degradation of the receptor that affects the survival of sensory neurons. The dorsal root ganglia from the TrkAP782S knock-in mice display an increased number of neurons expressingCGRPandsubstance P. Moreover, the mutant mice show enhanced sensitivity to thermal and inflammatory pain. Our results indicate that the ubiquitination of the TrkA neurotrophin receptor plays a critical role in NGF-mediated functions, such as neuronal survival and sensitivity to pain.
Modulation Dynamics in the Orofacial Sensorimotor Cortex during Motor Skill Acquisition
Authors: Arce-McShane Fritzie I. , Hatsopoulos Nicholas G. , Lee Jye-Chang , Ross Callum F. , Sessle Barry J.
Published: April 2014

The orofacial sensorimotor cortex is known to play a role in motor learning. However, how motor learning changes the dynamics of neuronal activity and whether these changes differ between orofacial primary motor (MIo) and somatosensory (SIo) cortices remain unknown. To address these questions, we used chronically implanted microelectrode arrays to track learning-induced changes in the activity of simultaneously recorded neurons in MIo and SIo as two naive monkeys (Macaca mulatta) were trained in a novel tongue-protrusion task. Over a period of 8–12 d, the monkeys showed behavioral improvements in task performance that were accompanied by rapid and long-lasting changes in neuronal responses in MIo and SIo occurring in parallel: (1) increases in the proportion of task-modulated neurons, (2) increases in the mutual information between tongue-protrusive force and spiking activity, (3) reductions in the across-trial firing rate variability, and (4) transient increases in coherent firing of neuronal pairs. More importantly, the time-resolved mutual information in MIo and SIo exhibited temporal alignment. While showing parallel changes, MIo neurons exhibited a bimodal distribution of peak correlation lag times between spiking activity and force, whereas SIo neurons showed a unimodal distribution. Moreover, coherent activity between pairs of MIo neurons was higher and centered around force onset compared with pairwise coherence of SIo neurons. Overall, the results suggest that the neuroplasticity in MIo and SIo occurring in parallel serves as a substrate for linking sensation and movement during sensorimotor learning, whereas the differing dynamic organizations reflect specific ways to control movement parameters as learning progresses.
Progressive Degeneration of Dopaminergic Neurons through TRP Channel-Induced Cell Death
Authors: Nagarajan Archana , Ning Ye , Reisner Kaja , Buraei Zafir , Larsen Jan Petter , Hobert Oliver , Doitsidou Maria
Published: April 2014

Progressive neurodegenerative diseases are among the most frequently occurring aging-associated human pathologies. In a screen forCaenorhabditis elegansmutant animals that lack their normal complement of dopaminergic neurons, we identified two strains with progressive loss of dopaminergic neurons during postembryonic life. Through whole-genome sequencing we show that both strains harbor dominant (d), gain-of-function mutations in the Transient Receptor Potential (TRP) mechanosensory channeltrp-4, a member of the invertebrate and vertebrate TRPN-type of the TRP family channels. Gain-of-function mutations in TRP channels have not been previously implicated in dopaminergic neuronal degeneration. We show thattrp-4(d)induces cell death in dopamine neurons through a defined, calcium-related downstream pathway.
Alpha Power Gates Relevant Information during Working Memory Updating
Authors: Manza Peter , Hau Chui Luen Vera , Leung Hoi-Chung
Published: April 2014

Human working memory (WM) is inherently limited, so we must filter out irrelevant information in our environment or our mind while retaining limited important relevant contents. Previous work suggests that neural oscillations in the alpha band (8–14 Hz) play an important role in inhibiting incoming distracting information during attention and selective encoding tasks. However, whether alpha power is involved in inhibiting no-longer-relevant content or in representing relevant WM content is still debated. To clarify this issue, we manipulated the amount of relevant/irrelevant information using a task requiring spatial WM updating while measuring neural oscillatory activity via EEG and localized current sources across the scalp using a surface Laplacian transform. An initial memory set of two, four, or six spatial locations was to be memorized over a delay until an updating cue was presented indicating that only one or three locations remained relevant for a subsequent recognition test. Alpha amplitude varied with memory maintenance and updating demands among a cluster of left frontocentral electrodes. Greater postcue alpha power was associated with the high relevant load conditions (six and four dots cued to reduce to three relevant) relative to the lower load conditions (four and two dots reduced to one). Across subjects, this difference in alpha power was correlated with condition differences in performance accuracy. In contrast, no significant effects of irrelevant load were observed. These findings demonstrate that, during WM updating, alpha power reflects maintenance of relevant memory contents rather than suppression of no-longer-relevant memory traces.
CNS Axons Globally Increase Axonal Transport after Peripheral Conditioning
Authors: Mar Fernando M. , Simões Anabel R. , Leite Sérgio , Morgado Marlene M. , Santos Telma E. , Rodrigo Inês S. , Teixeira Carla A. , Misgeld Thomas , Sousa Mónica M.
Published: April 2014

Despite the inability of CNS axons to regenerate, an increased regenerative capacity can be elicited following conditioning lesion to the peripheral branch of dorsal root ganglia neurons (DRGs). Byin vivoradiolabeling of rat DRGs, coupled to mass spectrometry and kinesin immunoprecipitation of spinal cord extracts, we determined that the anterograde transport of cytoskeleton components, metabolic enzymes and axonal regeneration enhancers, was increased in the central branch of DRGs following a peripheral conditioning lesion. Axonal transport of mitochondria was also increased in the central branch ofThy1-MitoCFPmice following a peripheral injury. This effect was generalized and included augmented transport of lysosomes and synaptophysin- and APP-carrying vesicles. Changes in axonal transport were only elicited by a peripheral lesion and not by spinal cord injury. In mice, elevated levels of motors and of polyglutamylated and tyrosinated tubulin were present following a peripheral lesion and can explain the increase in axonal transport induced by conditioning. In summary, our work shows that a peripheral injury induces a global increase in axonal transport that is not restricted to the peripheral branch, and that, by extending to the central branch, allows a rapid and sustained support of regenerating central axons.
Motion Integration for Ocular Pursuit Does Not Hinder Perceptual Segregation of Moving Objects
Authors: Jin Zhenlan , Watamaniuk Scott N.J. , Khan Aarlenne Z. , Potapchuk Elena , Heinen Stephen J.
Published: April 2014

When confronted with a complex moving stimulus, the brain can integrate local element velocities to obtain a single motion signal, or segregate the elements to maintain awareness of their identities. The integrated motion signal can drive smooth-pursuit eye movements (Heinen and Watamaniuk, 1998), whereas the segregated signal guides attentive tracking of individual elements in multiple-object tracking tasks (MOT; Pylyshyn and Storm, 1988). It is evident that these processes can occur simultaneously, because we can effortlessly pursue ambulating creatures while inspecting disjoint moving features, such as arms and legs, but the underlying mechanism is unknown. Here, we provide evidence that separate neural circuits perform the mathematically opposed operations of integration and segregation, by demonstrating with a dual-task paradigm that the two processes do not share attentional resources. Human observers attentively tracked a subset of target elements composing a small MOT stimulus, while pursuing it ocularly as it translated across a computer display. Integration of the multidot stimulus yielded optimal pursuit. Importantly, performing MOT while pursuing the stimulus did not degrade performance on either task compared with when each was performed alone, indicating that they did not share attention. A control experiment showed that pursuit was not driven by integration of only the nontargets, leaving the MOT targets free for segregation. Nor was a predictive strategy used to pursue the stimulus, because sudden changes in its global velocity were accurately followed. The results suggest that separate neural mechanisms can simultaneously segregate and integrate the same motion signals.
Structural Plasticity within the Barrel Cortex during Initial Phases of Whisker-Dependent Learning
Authors: Kuhlman Sandra J. , O'Connor Daniel H. , Fox Kevin , Svoboda Karel
Published: April 2014

We report learning-related structural plasticity in layer 1 branches of pyramidal neurons in the barrel cortex, a known site of sensorimotor integration. In mice learning an active, whisker-dependent object localization task, layer 2/3 neurons showed enhanced spine growth during initial skill acquisition that both preceded and predicted expert performance. Preexisting spines were stabilized and new persistent spines were formed. These findings suggest rapid changes in connectivity between motor centers and sensory cortex guide subsequent sensorimotor learning.
Corticostriatal Coordination through Coherent Phase-Amplitude Coupling
Authors: von Nicolai Constantin , Engler Gerhard , Sharott Andrew , Engel Andreas K. , Moll Christian K. , Siegel Markus
Published: April 2014

The corticostriatal axis is the main input stage of the basal ganglia and is crucial for their role in motor behavior. Synchronized oscillations might mediate interactions between cortex and striatum during behavior, yet direct evidence remains sparse. Here, we show that, during motor behavior, low- and high-frequency oscillations jointly couple cortex and striatum via cross-frequency interactions. We investigated neuronal oscillations along the corticostriatal axis in rats during rest and treadmill running. We found prominent theta and gamma oscillations in cortex and striatum, the peak frequencies of which scaled with motor demand. Theta and gamma oscillations were functionally coupled through phase-amplitude coupling. Furthermore, theta oscillations were phase coupled between structures. Together, local phase-amplitude coupling and corticostriatal theta phase coupling mediated the temporal correlation of gamma bursts between the cortex and striatum. The coordination of fast oscillations through coherent phase-amplitude coupling may be a general mechanism to regulate neuronal interactions along the corticostriatal axis and beyond.
Decoding Ventromedial Hypothalamic Neural Activity during Male Mouse Aggression
Authors: Falkner Annegret L. , Dollar Piotr , Perona Pietro , Anderson David J. , Lin Dayu
Published: April 2014

The ventromedial hypothalamus, ventrolateral area (VMHvl) was identified recently as a critical locus for inter-male aggression. Optogenetic stimulation of VMHvl in male mice evokes attack toward conspecifics and inactivation of the region inhibits natural aggression, yet very little is known about its underlying neural activity. To understand its role in promoting aggression, we recorded and analyzed neural activity in the VMHvl in response to a wide range of social and nonsocial stimuli. Although response profiles of VMHvl neurons are complex and heterogeneous, we identified a subpopulation of neurons that respond maximally during investigation and attack of male conspecific mice and during investigation of a source of male mouse urine. These “male responsive” neurons in the VMHvl are tuned to both the inter-male distance and the animal's velocity during attack. Additionally, VMHvl activity predicts several parameters of future aggressive action, including the latency and duration of the next attack. Linear regression analysis further demonstrates that aggression-specific parameters, such as distance, movement velocity, and attack latency, can model ongoing VMHvl activity fluctuation during inter-male encounters. These results represent the first effort to understand the hypothalamic neural activity during social behaviors using quantitative tools and suggest an important role for the VMHvl in encoding movement, sensory, and motivation-related signals.
Slow Oscillations in the Mouse Hippocampus Entrained by Nasal Respiration
Authors: Yanovsky Yevgenij , Ciatipis Mareva , Draguhn Andreas , Tort Adriano B.L. , Brankačk Jurij
Published: April 2014

Different types of network oscillations occur in different behavioral, cognitive, or vigilance states. The rodent hippocampus expresses prominent θ oscillations at frequencies between 4 and 12 Hz, which are superimposed by phase-coupled γ oscillations (30–100 Hz). These patterns entrain multineuronal activity over large distances and have been implicated in sensory information processing and memory formation. Here we report a new type of oscillation at near-θ frequencies (2–4 Hz) in the hippocampus of urethane-anesthetized mice. The rhythm is highly coherent with nasal respiration and with rhythmic field potentials in the olfactory bulb: hence, we called it hippocampal respiration-induced oscillations. Despite the similarity in frequency range, several features distinguish this pattern from locally generated θ oscillations: hippocampal respiration-induced oscillations have a unique laminar amplitude profile, are resistant to atropine, couple differently to γ oscillations, and are abolished when nasal airflow is bypassed by tracheotomy. Hippocampal neurons are entrained by both the respiration-induced rhythm and concurrent θ oscillations, suggesting a direct interaction between endogenous activity in the hippocampus and nasal respiratory inputs. Our results demonstrate that nasal respiration strongly modulates hippocampal network activity in mice, providing a long-range synchronizing signal between olfactory and hippocampal networks.
Crtc1 Activates a Transcriptional Program Deregulated at Early Alzheimer's Disease-Related Stages
Authors: Parra-Damas Arnaldo , Valero Jorge , Chen Meng , España Judit , Martín Elsa , Ferrer Isidro , Rodríguez-Alvarez José , Saura Carlos A.
Published: April 2014

Cognitive decline is associated with gene expression changes in the brain, but the transcriptional mechanisms underlying memory impairments in cognitive disorders, such as Alzheimer's disease (AD), are largely unknown. Here, we aimed to elucidate relevant mechanisms responsible for transcriptional changes underlying early memory loss in AD by examining pathological, behavioral, and transcriptomic changes in control and mutant β-amyloid precursor protein (APPSw,Ind) transgenic mice during aging. Genome-wide transcriptome analysis using mouse microarrays revealed deregulation of a gene network related with neurotransmission, synaptic plasticity, and learning/memory in the hippocampus of APPSw,Indmice after spatial memory training. Specifically, APPSw,Indmice show changes on a cAMP-responsive element binding protein (CREB)-regulated transcriptional program dependent on the CREB-regulated transcription coactivator-1 (Crtc1). Interestingly, synaptic activity and spatial memory induces Crtc1 dephosphorylation (Ser151), nuclear translocation, and Crtc1-dependent transcription in the hippocampus, and these events are impaired in APPSw,Indmice at early pathological and cognitive decline stages. CRTC1-dependent genes and CRTC1 levels are reduced in human hippocampus at intermediate Braak III/IV pathological stages. Importantly, adeno-associated viral-mediated Crtc1 overexpression in the hippocampus efficiently reverses Aβ-induced spatial learning and memory deficits by restoring a specific subset of Crtc1 target genes. Our results reveal a critical role of Crtc1-dependent transcription on spatial memory formation and provide the first evidence that targeting brain transcriptome reverses memory loss in AD.