bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Role of the Dorsal Anterior Cingulate in Evaluating Behavior for Achieving Gains and Avoiding Losses
Authors: Magno Elena , Simões-Franklin Cristina , Robertson Ian H. , Garavan Hugh 
Published: December 2008

AbstractEffective goal-directed behavior relies on a network of regions including anterior cingulate cortex and ventral striatum to learn from negative outcomes in order to improve performance. We employed fMRI to determine if this frontal–striatal system is also involved in instances of behavior that do not presume negative circumstances. Participants performed a visual target/nontarget search game in which they could optionally abort a trial to avoid errors or receive extra reward for highly confident responses. Anterior cingulate and prefrontal cortex were equally activated for error avoidance and high reward trials but were not active on error trials, demonstrating their primary involvement in self-initiated behavioral adjustment and not error detection or prediction. In contrast, the insula and the ventral striatum were responsive to the high reward trials. Differential activation patterns across conditions for the nucleus accumbens, insula, and prefrontal cortex suggest distinct roles for these structures in the control of reward-related behavior.
Now You'll Feel It, Now You Won't: EEG Rhythms Predict the Effectiveness of Perceptual Masking
Authors: Schubert Ruth , Haufe Stefan , Blankenburg Felix , Villringer Arno , Curio Gabriel 
Published: December 2008

Abstract
Do ongoing brain states determine conscious perception of an upcoming stimulus? Using the high temporal resolution of EEG, we investigated the relationship between prestimulus neuronal oscillations and the perceptibility of two competing somatosensory stimuli embedded in a backward masking paradigm. We identified two prestimulus EEG signatures predictive for a suprathreshold yet weak target stimulus to become perceptually resistant against masking by a stronger distractor stimulus: (i) over left frontal cortex a desynchronization of the regional beta rhythm (∼20 Hz) 500 msec prior to a perceived target, and (ii) a subsequent additional attenuation of both mu (∼10 Hz) and beta “idling” rhythms over those pericentral sensorimotor cortices which are going to process the upcoming target stimulus. Furthermore, across subjects the probability for target perception strongly correlates with the individual absolute level of pre-target amplitudes in these frequency bands and locations. These signatures significantly differed from the EEG characteristics preceding detected and undetected single stimuli. We suggest that the early activation of left frontal areas involved in top–down attentional control is critical for preventing backward masking and leads the preparation of primary sensory cortices: The ensuing prestimulus suppression of sensory idling rhythms warrants an intensified poststimulus processing, and thus, effectively promotes conscious perception of suprathreshold target stimuli embedded into an ecologically relevant condition featuring competing environmental stimuli.
The Timing of Neural Activity during Shifts of Spatial Attention
Authors: Brignani Debora , Lepsien Jöran , Rushworth Matthew F. S. , Nobre Anna Christina 
Published: December 2008

Abstract
We developed a new experimental task to investigate the relative timing of neural activity during shifts of spatial attention with event-related potentials. The task enabled the investigation of nonlateralized as well as lateralized neural activity associated with spatial shifts. Participants detected target stimuli within one of two peripheral streams of visual letters. Colored letters embedded within the streams indicated which stream was to be used for target detection, signaling that participants should “hold” or “shift” their current focus of spatial attention. A behavioral experiment comparing performance in these focused-attention conditions with performance in a divided-attention condition confirmed the efficacy of the spatial cues. Another behavioral experiment showed that overt shifts of spatial attention were mainly complete by around 400 msec, placing an upper boundary for isolating neural activity that was instrumental in controlling spatial shifts. Event-related potentials recorded during a covert version of the focused-attention task showed a large amount of nonlateralized neural activity associated with spatial shifts, with significant effects starting around 330 msec. The effects started over posterior scalp regions, where they remained pronounced. Transient effects were also observed over frontal scalp regions. The results are compatible with a pivotal role of posterior parietal areas in initiating shifts of spatial attention.
Neural Correlates of Cross-modally Induced Changes in Tactile Awareness
Authors: Hötting Kirsten , Friedrich Claudia K. , Röder Brigitte 
Published: December 2008

AbstractWhen a single tactile stimulus is presented together with two tones, participants often report perceiving two touches. It is a matter of debate whether this cross-modal effect of audition on touch reflects the interplay between modalities at early perceptual or at later processing stages, and which brain processes determine what in the end is consciously perceived. Event-related brain potentials (ERPs) were recorded while rare single tactile stimuli accompanied by two tones (1T2A) were presented among frequent tactile double stimuli accompanied by two tones (2T2A). Although participants were instructed to ignore the tones and to respond to single tactile stimuli only, they often failed to respond to 1T2A stimuli (“illusory double touches,” 1T2A(i)). ERPs to “illusory double touches” versus “real double touches” (2T2A) differed 50 msec after the (missing) second touch. This suggests that at an early sensory stage, illusory and real touches are processed differently. On the other hand, although similar stimuli elicited a tactile mismatch negativity (MMN) between 100 and 200 msec in a unisensory tactile experiment, no MMN was observed for the 1T2A(i) stimuli in the multisensory experiment. “Tactile awareness” was associated with a negativity at 250 msec, which was enhanced in response to correctly identified deviants as compared to physically identical deviants that elicited an illusion. Thus, auditory stimuli seem to alter neural mechanisms associated with automatic tactile deviant detection. The present findings contribute to the debate of which processing step in the brain determines what is consciously perceived.
Interactions between Voluntary and Stimulus-driven Spatial Attention Mechanisms across Sensory Modalities
Authors: Santangelo Valerio , Belardinelli Marta Olivetti , Spence Charles , Macaluso Emiliano 
Published: December 2008

Abstract
In everyday life, the allocation of spatial attention typically entails the interplay between voluntary (endogenous) and stimulus-driven (exogenous) attention. Furthermore, stimuli in different sensory modalities can jointly influence the direction of spatial attention, due to the existence of cross-sensory links in attentional control. Using fMRI, we examined the physiological basis of these interactions. We induced exogenous shifts of auditory spatial attention while participants engaged in an endogenous visuospatial cueing task. Participants discriminated visual targets in the left or right hemifield. A central visual cue preceded the visual targets, predicting the target location on 75% of the trials (endogenous visual attention). In the interval between the endogenous cue and the visual target, task-irrelevant nonpredictive auditory stimuli were briefly presented either in the left or right hemifield (exogenous auditory attention). Consistent with previous unisensory visual studies, activation of the ventral fronto-parietal attentional network was observed when the visual targets were presented at the uncued side (endogenous invalid trials, requiring visuospatial reorienting), as compared with validly cued targets. Critically, we found that the side of the task-irrelevant auditory stimulus modulated these activations, reducing spatial reorienting effects when the auditory stimulus was presented on the same side as the upcoming (invalid) visual target. These results demonstrate that multisensory mechanisms of attentional control can integrate endogenous and exogenous spatial information, jointly determining attentional orienting toward the most relevant spatial location.
ERP Evidence for Rapid Hedonic Evaluation of Logos
Authors: Handy Todd C. , Smilek Daniel , Geiger Lena , Liu Cindy , Schooler Jonathan W. 
Published: December 2008

Abstract
We know that human neurocognitive systems rapidly and implicitly evaluate emotionally charged stimuli. But what about more everyday, frequently encountered kinds of objects, such as computer desktop icons and business logos? Do we rapidly and implicitly evaluate these more prosaic visual images, attitude objects that might only engender a mild sense of liking or disliking, if at all? To address this question, we asked participants to view a set of unfamiliar commercial logos in the context of a target identification task as brain electrical responses to these objects were recorded via event-related potentials (ERPs). Following this task, participants individually identified those logos that were most liked or disliked, allowing us to then compare how ERP responses to logos varied as a function of hedonic evaluation—a procedure decoupling evaluative responses from any normative classification of the logos themselves. In Experiment 1, we found that visuocortical processing manifest a specific bias for disliked logos that emerged within the first 200 msec of stimulus onset. In Experiment 2, we replicated this effect while dissociating normative- and novelty-related influences. Taken together, our results provide direct electrophysiological evidence suggesting that we rapidly and implicitly evaluate commercial branding images at a hedonic level.
Order and Magnitude Share a Common Representation in Parietal Cortex
Authors: Franklin Michael S. , Jonides John 
Published: December 2008

Abstract
The role of the intraparietal sulcus (IPS) in the representation of numerical magnitude is well established. Recently, there has also been speculation that the IPS is involved in the representation of ordinal information as well. These claims, however, overlook the fact that all neuroimaging paradigms in which participants make judgments about either magnitude and/or order result in a behavioral distance effect (i.e., the comparison is easier when the stimuli span a greater distance). This leaves open two possibilities: It may be that activation of the IPS is due to the mechanism that yields distance effects, or it may be that the IPS is involved in the representation of information about both magnitude and order. The current study used fMRI to compare a magnitude task in which participants show distance effects to an order-judgment task that yields reverse-distance effects. The results reveal activation of the IPS for both the magnitude and order tasks that is based on participants' strategies as opposed to the actual distance between the numbers. This leads to the conclusion that the IPS represents a mental number line, and that accessing this line can lead to distance effects when participants compare magnitudes and to reverse-distance effects when participants check for order.
Coordination Dynamics of Large-scale Neural Circuitry Underlying Rhythmic Sensorimotor Behavior
Authors: Jantzen Kelly J. , Steinberg Fred L. , Kelso J. A. Scott 
Published: December 2008

Abstract
In coordination dynamics, rate is a nonspecific control parameter that alters the stability of behavioral patterns and leads to spontaneous pattern switching. We used fMRI in conjunction with measures of effective connectivity to investigate the neural basis of behavioral dynamics by examining two coordination patterns known to be differentially stable (synchronization and syncopation) across a range of rates (0.75 to 1.75 Hz). Activity in primary auditory and motor cortices increased linearly with rate, independent of coordination pattern. On the contrary, activity in a premotor–cerebellar circuit varied directly with the stability of the collective variable (relative phase) that specifies coordinated behavioral patterns. Connectivity between premotor and motor cortices was also modulated by the stability of the behavioral pattern indicative of greater reliance on sensorimotor integration as action becomes more variable. By establishing a critical connection between behavioral and large scale brain dynamics, these findings reveal a basic principle for the neural organization underlying coordinated action.
Simulated WSR-88D Velocity and Reflectivity Signatures of Numerically Modeled Tornadoes
Authors: Wood Vincent T. , Brown Rodger A. , Dowell David C. 
Published: December 2008

Abstract
Low-altitude radar reflectivity measurements of tornadoes sometimes reveal a donut-shaped signature (low-reflectivity eye surrounded by a high-reflectivity annulus) and at other times reveal a high-reflectivity knob associated with the tornado. The differences appear to be due to such factors as (i) the radar’s sampling resolution, (ii) the presence or absence of lofted debris and a low-reflectivity eye, (iii) whether measurements were made within the lowest few hundred meters where centrifuged hydrometeors and smaller debris particles were recycled back into the tornadic circulation, and (iv) the presence or absence of multiple vortices in the parent tornado.
To explore the influences of some of these various factors on radar reflectivity and Doppler velocity signatures, a high-resolution tornado numerical model was used that incorporated the centrifuging of hydrometeors. A model reflectivity field was computed from the resulting concentration of hydrometeors. Then, the model reflectivity and velocity fields were scanned by a simulated Weather Surveillance Radar-1988 Doppler (WSR-88D) using both the legacy resolution and the new super-resolution sampling. Super-resolution reflectivity and Doppler velocity data are displayed at 0.5° instead of 1.0° azimuthal sampling intervals and reflectivity data are displayed at 0.25-km instead of 1.0-km range intervals.
Since a mean Doppler velocity value is the reflectivity-weighted mean of the radial motion of all the radar scatterers within a radar beam, a nonuniform distribution of scatterers produces a different mean Doppler velocity value than does a uniform distribution of scatterers. Nonuniform reflectivities within the effective resolution volume of the radar beam can bias the indicated size and strength of the tornado’s core region within the radius of the peak tangential velocities. As shown in the simulation results, the Doppler-indicated radius of the peak wind underestimates the true radius and true peak tangential velocity when the effective beamwidth is less than the tornado’s core diameter and there is a weak-reflectivity eye at the center of the tornado. As the beam becomes significantly wider than the tornado’s core diameter with increasing range, the peaks of the Doppler velocity profiles continue to decrease in magnitude but overestimate the tornado’s true radius. With increasing range from the radar, the prominence of the weak-reflectivity eye at the center of the tornado is progressively lessened until it finally disappears. As to be expected, the Doppler velocity signatures and reflectivity eye signatures were more prominent and stronger with super-resolution sampling than those with legacy-resolution sampling.
Structure of the Notch1-negative regulatory region: implications for normal activation and pathogenic signaling in T-ALL
Authors: Gordon Wendy R. , Roy Monideepa , Vardar-Ulu Didem , Garfinkel Megan , Mansour Marc R. , Aster Jon C. , Blacklow Stephen C. 
Published: December 2008

AbstractProteolytic resistance of Notch prior to ligand binding depends on the structural integrity of a negative regulatory region (NRR) of the receptor that immediately precedes the transmembrane segment. The NRR includes the 3 Lin12/Notch repeats and the juxtamembrane heterodimerization domain, the region of Notch1 most frequently mutated in T-cell acute lymphoblastic leukemia lymphoma (T-ALL). Here, we report the x-ray structure of the Notch1 NRR in its autoinhibited conformation. A key feature of the Notch1 structure that maintains its closed conformation is a conserved hydrophobic plug that sterically occludes the metalloprotease cleavage site. Crystal packing interactions involving a highly conserved, exposed face on the third Lin12/Notch repeat suggest that this site may normally be engaged in intermolecular or intramolecular protein-protein interactions. The majority of known T-ALL–associated point mutations map to residues in the hydrophobic interior of the Notch1 NRR. A novel mutation (H1545P), which alters a residue at the crystal-packing interface, leads to ligand-independent increases in signaling in reporter gene assays despite only mild destabilization of the NRR, suggesting that it releases the autoinhibitory clamp on the heterodimerization domain imposed by the Lin12/Notch repeats. The Notch1 NRR structure should facilitate a search for antibodies or compounds that stabilize the autoinhibited conformation.
A Facile Method to Prepare Hollow MCM-41 Microspheres via P(St-MPS)/MCM-41 Core/Shell Composite Microspheres
Authors: Zhao Yansheng , Chen Kai , Liu Yongmei , Guo Meijuan , Ma Xingji , Yuan Guangwei , Shen Yinghua 
Published: December 2008

Abstract
Hollow MCM-41 microspheres were obtained by removing the templates of poly(styrene-γ-methacrylic propyltrimethoxysilane)/MCM-41 [P(St-MPS)/MCM-41] core/shell composite microspheres prepared using P(St-MPS) microspheres contained in soap-free emulsion and cetyltrimethylammonium bromide as cotemplates. XRD, TEM, and IR measurements show that the pore channels of MCM-41 shell were hexagonally ordered and that the diameter of the hollow microspheres and the thickness of the shells were about 260 and 30 nm, respectively.
Gelation of a Composite of Ceramic Fibers and Polypropylene Modified with Maleic Anhydrate in Naphthenic Oil
Authors: Machida Shigeru , Matsuda Yasuhiro , Tasaka Shigeru 
Published: December 2008

Abstract
The physical gelation of isotactic polypropylene in naphthenic oil was drastically enhanced by adding a small amount of ceramic fibers after modification of polypropylene with maleic anhydrate. The micrograph of the gel showed the network of ceramic fibers crosslinked with polypropylene crystals formed by nucleation at the surface of the fibers.
Where Wnts Went: The Exploding Field of Lrp5 and Lrp6 Signaling in Bone
Authors: Williams Bart O , Insogna Karl L 
Published: December 2008

Abstract
Wnt signaling has emerged as a central regulator of skeletal modeling and remodeling. Loss- or gain-of-function mutations in two Wnt co-receptors, Lrp5 and (more recently) Lrp6, have drawn attention to the importance of the Wnt pathway in bone biology. This review summarizes our current understanding of how the Wnt pathway operates on bone and the implications this has for skeletal physiology and drug discovery. Over the past 9 yr, rapid advances have been made in our understanding of the cellular targets for Wnt signaling and of the important regulatory molecules in this metabolic pathway. Both canonical and noncanonical signaling pathways seem to be important for mediating the effects of Wnt in bone. A rapidly expanding catalog of genetically engineered mice has been used to establish the importance of downstream effector molecules (such as β-catenin) in the Wnt pathway, as well as the critical role of endogenous inhibitors of Wnt signaling (such as Dkk1 and sclerostin) in bone metabolism. Indeed, regulation of sclerostin in osteocytes is emerging as an important final pathway for regulating bone anabolism in response to diverse trophic stimuli, from mechnotransduction to the anabolic actions of PTH. From the outset, it had been assumed that the effects of Wnt signaling in bone were caused by direct actions in osteoblast precursors, osteoblasts, and osteocytes. However, startling recent findings have challenged this view and suggest that a key target, at least in mice, is the duodenal enterochromaffin cell. There, Wnt signaling transduced by Lrp5 regulates serotonin synthesis, which acts in an endocrine fashion to regulate bone cell metabolism. It will take time to reconcile this new information with the considerable body of information we already have regarding the actions of Wnt in bone. The Wnt pathway has rapidly emerged as a therapeutic target for drug discovery. Neutralizing antibodies and small-molecule inhibitors of endogenous Wnt inhibitors have shown early promise as bone anabolic agents. However, given the central role of the Wnt pathway in regulating growth and development in extraskeletal tissues, as well as our still rudimentary understanding of how this signaling cascade actually affects bone metabolism, considerable work will be needed to ensure the safety of these new therapies.
Array CGH in the routine diagnostic work-up of mental retardation1
Authors: Heinrich Uwe , von Voss Hubertus , Rost Imma 
Published: December 2008

Abstract
Array CGH (Comparative Genomic Hybridisation) analysis has become an essential part of the diagnostic work-up of mental retardation in children. Using BAC- (Bacterial Artificial Chromosome) array CGH, a follow-up examination on chromosomally inconspicuous children with mental retardation (n=194) revealed in 20 patients (10.4%) a chromosomal imbalance as the cause of retardation. In a small pilot study on ten patients, we were able to demonstrate the benefit of applying a second, oligonucleotide-based array CGH platform as a reliable and rapid validation tool for ambiguous CGH results, in particular, if duplications were suspected (cross validation). Based on our own experience and that of other groups, a stepwise approach for the diagnosis of mental retardation in children involving a combination of BAC- and oligonucleotide array CGH as well as fluorescence in situ hybridisation (FISH) is recommended.
Procalcitonin: Importance for the diagnosis of bacterial infections1
Authors: Christ-Crain Mirjam , Schuetz Philipp , Huber Andreas R. , Müller Beat 
Published: December 2008

Abstract
In contrast to calcitonin which is primarily synthesized in the thyroid, procalcitonin is a prohormone which is synthesized in many different tissues of infected organs. To diagnose mild, localized, or early infections an assay needs to have a functional assay sensivity of approximately 0.02 μg/L. We demonstrated that procalcitonin modifies the outcome of respiratory infections with regard to minimizing the use of antibiotics and duration of antibiotic treatment. High concentrations, especially over time, indicate high risk of a severe outcome. In this respect, procalcitonin is superior to other infection markers, such as C-reactive protein. High procalcitonin levels can also be found in non-bacterial diseases, such as malaria, severe trauma, burns, and medullar carcinoma of the thyroid. Procalcitonin, as a marker, has improved the diagnosis of bacterial infections. However, procalcitonin needs to be used in conjunction with other laboratory markers, clinical examination, and medical history.