bluuebunny/crossref_metadata_2025_split huggingface dataset:
Temporal Order is Coded Temporally in the Brain: Early Event-related Potential Latency Shifts Underlying Prior Entry in a Cross-modal Temporal Order Judgment Task
Authors: Vibell J. , Klinge C. , Zampini M. , Spence C. , Nobre A. C. 
Published: January 2007

Abstract
The speeding-up of neural processing associated with attended events (i.e., the prior-entry effect) has long been proposed as a viable mechanism by which attention can prioritize our perception and action. In the brain, this has been thought to be regulated through a sensory gating mechanism, increasing the amplitudes of early evoked potentials while leaving their latencies unaffected. However, the majority of previous research has emphasized speeded responding and has failed to emphasize fine temporal discrimination, thereby potentially lacking the sensitivity to reveal putative modulations in the timing of neural processing. In the present study, we used a cross-modal temporal order judgment task while shifting attention between the visual and tactile modalities to investigate the mechanisms underlying selective attention electrophysiologically. Our results indicate that attention can indeed speed up neural processes during visual perception, thereby providing the first electrophysiological support for the existence of prior entry.
Expectancy Induces Dynamic Modulation of Corticospinal Excitability
Authors: van Elswijk Gijs , Kleine Bert U. , Overeem Sebastiaan , Stegeman Dick F. 
Published: January 2007

Abstract
Behavioral studies using motor preparation paradigms have revealed that increased expectancy of a response signal shortens reaction times (RTs). Neurophysiological data suggest that in such paradigms, not only RT but also neuronal activity in the motor structures involved is modulated by expectancy of behaviorally relevant events. Here, we directly tested whether expectancy of a response signal modulates excitability of the corticospinal system used in the subsequent movement. We combined single- and paired-pulse transcranial magnetic stimulation (TMS) over the primary motor cortex with a simple RT task with variable preparatory delays. We found that, in line with typical behavioral observations, the subjects' RTs decreased with increasing response signal expectancy. TMS results revealed a modulation of corticospinal excitability in correspondence with response signal expectancy. Besides an increased excitability over the time-course of the preparatory delay, corticospinal excitability transiently increased whenever a response signal was expected. Paired-pulse TMS showed that this modulation is unlikely to be mediated by excitability changes in interneuronal inhibitory or facilitatory networks in the primary motor cortex. Changes in corticospinal synchronization or other mechanisms involving spinal circuits are candidates mediating the modulation of corticospinal excitability by expectancy.
The Role of the Lateral Prefrontal Cortex and Anterior Cingulate in Stimulus-Response Association Reversals
Authors: Parris Benjamin A. , Thai Ngoc J. , Benattayallah Abdelmalek , Summers Ian R. , Hodgson Timothy L. 
Published: January 2007

Abstract
Many complex tasks require us to flexibly switch between behavioral rules, associations, and strategies. The prefrontal cerebral cortex is thought to be critical to the performance of such behaviors, although the relative contribution of different components of this structure and associated subcortical regions are not fully understood. We used functional magnetic resonance imaging to measure brain activity during a simple task which required repeated reversals of a rule linking a colored cue and a left/right motor response. Each trial comprised three discrete events separated by variable delay periods. A colored cue instructed which response was to be executed, followed by a go signal which told the subject to execute the response and a feedback instruction which indicated whether to “hold” or “flip” the rule linking the colored cue and response. The design allowed us to determine which brain regions were recruited by the specific demands of preparing a rule contingent motor response, executing such a response, evaluating the significance of the feedback, and reconfiguring stimulus-response (SR) associations. The results indicate that an increase in neural activity occurs within the anterior cingulate gyrus under conditions in which SR associations are labile. In contrast, lateral frontal regions are activated by unlikely/unexpected perceptual events regardless of their significance for behavior. A network of subcortical structures, including the mediodorsal nucleus of the thalamus and striatum were the only regions showing activity that was exclusively correlated with the neurocognitive demands of reversing SR associations. We conclude that lateral frontal regions act to evaluate the behavioral significance of perceptual events, whereas medial frontal-thalamic circuits are involved in monitoring and reconfiguring SR associations when necessary.
Too Many Trees to See the Forest: Performance, Event-related Potential, and Functional Magnetic Resonance Imaging Manifestations of Integrative Congenital Prosopagnosia
Authors: Bentin Shlomo , DeGutis Joseph M. , D'Esposito Mark , Robertson Lynn C. 
Published: January 2007

Abstract
Neuropsychological, event-related potential (ERP), and functional magnetic resonance imaging (fMRI) methods were combined to provide a comprehensive description of performance and neurobiological profiles for K.W., a case of congenital prosopagnosia. We demonstrate that K.W.'s visual perception is characterized by almost unprecedented inability to identify faces, a large bias toward local features, and an extreme deficit in global/configural processing that is not confined to faces. This pattern could be appropriately labeled congenital integrative prosopagnosia, and accounts for some, albeit not all, cases of face recognition impairments without identifiable brain lesions. Absence of face selectivity is evident in both biological markers of face processing, fMRI (the fusiform face area [FFA]), and ERPs (N170). Nevertheless, these two neural signatures probably manifest different perceptual mechanisms. Whereas the N170 is triggered by the occurrence of physiognomic stimuli in the visual field, the deficient face-selective fMRI activation in the caudal brain correlates with the severity of global processing deficits. This correlation suggests that the FFA might be associated with global/configural computation, a crucial part of face identification.
The Role of the Cerebellum in Subsecond Time Perception: Evidence from Repetitive Transcranial Magnetic Stimulation
Authors: Lee Kwang-Hyuk , Egleston Paul N. , Brown Wendy H. , Gregory Abigail N. , Barker Anthony T. , Woodruff Peter W. R. 
Published: January 2007

Abstract
In three experiments, we investigated the role of the cerebellum in sub- and suprasecond time perception by using repetitive transcranial magnetic stimulation (rTMS). In Experiment 1, subjects underwent four 8-min 1-Hz rTMS sessions in a within-subject design. rTMS sites were the medial cerebellum (real and sham rTMS), left lateral cerebellum, and right lateral cerebellum. Following each rTMS session, subjects completed a subsecond temporal bisection task (stimuli in the range 400–800 msec). Compared with sham rTMS, rTMS applied over the right lateral or medial cerebellum induced a leftward shift of the psychophysical function (perceived lengthening of time). In Experiment 2, a separate sample of subjects underwent the identical rTMS procedure and completed a suprasecond bisection task (stimuli in the 1000–2000 msec range). In this experiment, rTMS to the cerebellar sites did not produce any significant changes compared with sham rTMS. Experiment 3 employed a within-subject design to replicate findings from Experiments 1 and 2. Subjects underwent four rTMS conditions (sub- and suprabisection tasks following medial cerebellar and sham rTMS). rTMS induced a significant leftward shift of psychophysical function in the subsecond bisection, but not in the suprasecond bisection. In this study, we have demonstrated that transient cerebellar stimulation can differently affect the ability to estimate time intervals below and above a duration of 1 sec. The results of this study provide direct evidence for the role of the cerebellum in processing subsecond time intervals. This study further suggests that the perception of sub- and suprasecond intervals is likely to depend upon distinct neural systems.
Brain Response to Unexpected Novel Noises in Children with Low and High Trait Anxiety
Authors: Hogan Alexandra M. , Butterfield Elinor L. , Phillips Luke , Hadwin Julie A. 
Published: January 2007

Abstract
The behavioral inhibition system [Gray, J. A. The neuropsychology of anxiety: An enquiry into the functions of the septo-hippocampal system. Oxford: Oxford University Press, 1982] proposes that anxiety is associated with the processing of novel stimuli. We aimed to explore this relationship by recording auditory event-related potentials associated with unexpected novel noises in typically developing children. Children aged 10–14 years with low (n = 12) and high (n = 11) self-report trait anxiety were assessed using a novelty oddball task. The N1 associated with novel stimuli, specifically the “N1c” component maximal at temporal lobe sites, was of significantly longer latency (p = .014) and greater amplitude (p = .004) in the high compared with the low anxious group. This group difference was supported by linear correlations between N1c amplitude and trait anxiety scores. There was no effect of anxiety on the later novelty P3. These data suggest a subtle moderating role of trait anxiety on brain response to novelty, and further research with clinically anxious children is indicated.
Genetic Variations of the NR3A Subunit of the NMDA Receptor Modulate Prefrontal Cerebral Activity in Humans
Authors: Gallinat Jürgen , Götz Thomas , Kalus Peter , Bajbouj Malek , Sander Thomas , Winterer Georg 
Published: January 2007

Abstract
Introduction: Recently, a novel N-methyl-D-aspartate (NMDA) receptor subunit, NR3A, has been discovered in the brain. This subunit decreases NMDA receptor activity by modulating the calcium permeability of the receptor channel and current density in cortical cells. Because the NR3A is expressed in the human prefrontal cortex, we hypothesized that genetic variations of the NR3A subunit modulate prefrontal activation. Methods: Electromagnetic activity during selective attention (auditory oddball task with target processing) was measured in 281 healthy subjects. Genotyping of a missense variation (rs10989591, Val362Met) of the NR3A gene was performed. Results: Individuals carrying Val/Val genotype showed significantly reduced frontal P300 amplitudes compared with Met/Met subjects. Subsequent low-resolution electromagnetic source analysis revealed that this group difference is likely caused by reduced activation in the inferior frontal gyrus. Conclusions: It was shown for the first time that the genetic constitution of the subunit composition of NMDA receptor regulation might be relevant for prefrontal information processing in humans. The results underline the pivotal role of glutamate in frontal lobe function and indicate that the NR3A subunit could be a plausible candidate gene for diseases with prefrontal dysfunctions.
Water Vapor Transport and the Production of Precipitation in the Eastern Fertile Crescent
Authors: Evans J. P. , Smith R. B. 
Published: January 2007

Abstract
The study presented here attempts to quantify the significance of southerly water vapor fluxes on precipitation occurring in the eastern Fertile Crescent region. The water vapor fluxes were investigated at high temporal and spatial resolution by using a Regional Climate Model [fifth-generation Pennsylvania State University–NCAR Mesoscale Model (MM5)–Noah land surface model] to downscale the NCEP–NCAR reanalysis. Using the Iterative Self-Organizing Data Analysis Techniques (ISODATA) clustering algorithm, the 200 largest precipitation events, occurring from 1990 through 1994, were grouped into classes based on the similarity of their water vapor fluxes. Results indicate that, while southerly fluxes were dominant in 24% of tested events, these events produced 43% of the total precipitation produced by the 200 largest events. Thus, while the majority of precipitation events occurring in the Fertile Crescent involve significant water vapor advected from the west, those events that included southerly fluxes produced much larger precipitation totals. This suggests that changes that affect these southerly fluxes more than the westerly fluxes (e.g., changes in the Indian monsoon, movement of the head of the Persian Gulf, etc.) may have a relatively strong affect on the total precipitation falling in the Fertile Crescent even though they affect relatively few precipitation events. To obtain a clearer view of the precipitation mechanisms, the authors used a linear model, along with the estimated water vapor fluxes, to downscale from 25 to 1 km. The result shows a spectrum of mountain scales not seen in the regional model, exerting tight control on the precipitation pattern.
Enhanced T-cell reconstitution by hematopoietic progenitors expanded ex vivo using the Notch ligand Delta1
Authors: Dallas Mari H. , Varnum-Finney Barbara , Martin Paul J. , Bernstein Irwin D. 
Published: January 2007

AbstractA physiologic role for Notch signaling in hematopoiesis has been clearly defined in lymphoid differentiation, with evidence suggesting a critical role in T-cell versus B-cell fate decisions. Previously, we demonstrated that activation of endogenous Notch receptors by culture of murine lin−Sca-1+c-kit+ (LSK) hematopoietic progenitors with exogenously presented Notch ligand, Delta1ext-IgG, consisting of the extracellular domain of Delta1 fused to the Fc domain of human IgG1, promoted early T-cell differentiation and increased the number of progenitors capable of short-term lymphoid and myeloid reconstitution. Here we show that culture of LSK precursors with Delta1ext-IgG increases the number of progenitors that are able to rapidly repopulate the thymus and accelerate early T-cell reconstitution with a diversified T-cell receptor repertoire. Most of the early T-cell reconstitution originated from cells that expressed lymphoid-associated antigens: B220, Thy1, CD25, and/or IL7Rα, whereas the most efficient thymic repopulation on a per cell basis originated from the smaller number of cultured cells that did not express lymphoid-associated antigens. These findings demonstrate the potential of Delta1ext-IgG-cultured cells for accelerating early immune reconstitution after hematopoietic cell transplantation.
Keratinocyte growth factor (KGF) enhances postnatal T-cell development via enhancements in proliferation and function of thymic epithelial cells
Authors: Rossi Simona W. , Jeker Lukas T. , Ueno Tomoo , Kuse Sachiyo , Keller Marcel P. , Zuklys Saulius , Gudkov Andrei V. , Takahama Yousuke , Krenger Werner , Blazar Bruce R. , Holländer Georg A. 
Published: January 2007

AbstractThe systemic administration of keratinocyte growth factor (KGF) enhances T-cell lymphopoiesis in normal mice and mice that received a bone marrow transplant. KGF exerts protection to thymic stromal cells from cytoablative conditioning and graft-versus-host disease–induced injury. However, little is known regarding KGF's molecular and cellular mechanisms of action on thymic stromal cells. Here, we report that KGF induces in vivo a transient expansion of both mature and immature thymic epithelial cells (TECs) and promotes the differentiation of the latter type of cells. The increased TEC numbers return within 2 weeks to normal values and the microenvironment displays a normal architectural organization. Stromal changes initiate an expansion of immature thymocytes and permit regular T-cell development at an increased rate and for an extended period of time. KGF signaling in TECs activates both the p53 and NF-κB pathways and results in the transcription of several target genes necessary for TEC function and T-cell development, including bone morphogenetic protein 2 (BMP2), BMP4, Wnt5b, and Wnt10b. Signaling via the canonical BMP pathway is critical for the KGF effects. Taken together, these data provide new insights into the mechanism(s) of action of exogenous KGF on TEC function and thymopoiesis.
Imatinib plus steroids induces complete remissions and prolonged survival in elderly Philadelphia chromosome–positive patients with acute lymphoblastic leukemia without additional chemotherapy: results of the Gruppo Italiano Malattie Ematologiche dell'Adulto (GIMEMA) LAL0201-B protocol
Authors: Vignetti Marco , Fazi Paola , Cimino Giuseppe , Martinelli Giovanni , Di Raimondo Francesco , Ferrara Felicetto , Meloni Giovanna , Ambrosetti Achille , Quarta Giovanni , Pagano Livio , Rege-Cambrin Giovanna , Elia Loredana , Bertieri Raffaello , Annino Luciana , Foà Robin , Baccarani Michele , Mandelli Franco 
Published: January 2007

AbstractThirty elderly (> 60 years) Philadelphia chromosome–positive (Ph+) patients with acute lymphoblastic leukemia (ALL) received imatinib, 800 mg daily, associated to steroids without further chemotherapy as frontline treatment. Median age was 69 years (range, 61-83 years). Twenty-nine patients were evaluable for response and all of them obtained a hematologic complete remission, with a median BCR-ABL reduction of 2.9 and 2.0 logs in p190+ and p210+ cases, respectively. Most of the induction treatment did not require admission of the patients. No major toxicities occurred and the treatment was well tolerated. Median survival from diagnosis was 20 months. This study shows that elderly Ph+ patients with ALL—often considered eligible only for palliative treatment strategies—may benefit from an imatinib-steroids protocol, which does not require chemotherapy nor a long hospitalization, is feasible, highly active, and associated with a good quality of life.
Bioinformatics analysis of the early inflammatory response in a rat thermal injury model
Authors: Yang Eric , Maguire Timothy , Yarmush Martin L , Berthiaume Francois , Androulakis Ioannis P 
Published: January 2007

AbstractBackgroundThermal injury is among the most severe forms of trauma and its effects are both local and systemic. Response to thermal injury includes cellular protection mechanisms, inflammation, hypermetabolism, prolonged catabolism, organ dysfunction and immuno-suppression. It has been hypothesized that gene expression patterns in the liver will change with severe burns, thus reflecting the role the liver plays in the response to burn injury. Characterizing the molecular fingerprint (i.e., expression profile) of the inflammatory response resulting from burns may help elucidate the activated mechanisms and suggest new therapeutic intervention. In this paper we propose a novel integrated framework for analyzing time-series transcriptional data, with emphasis on the burn-induced response within the context of the rat animal model. Our analysis robustly identifies critical expression motifs, indicative of the dynamic evolution of the inflammatory response and we further propose a putative reconstruction of the associated transcription factor activities.ResultsImplementation of our algorithm on data obtained from an animal (rat) burn injury study identified 281 genes corresponding to 4 unique profiles. Enrichment evaluation upon both gene ontologies and transcription factors, verifies the inflammation-specific character of the selections and the rationalization of the burn-induced inflammatory response. Conducting the transcription network reconstruction and analysis, we have identified transcription factors, including AHR, Octamer Binding Proteins, Kruppel-like Factors, and cell cycle regulators as being highly important to an organism's response to burn response. These transcription factors are notable due to their roles in pathways that play a part in the gross physiological response to burn such as changes in the immune response and inflammation.ConclusionOur results indicate that our novel selection/classification algorithm has been successful in selecting out genes with play an important role in thermal injury. Additionally, we have demonstrated the value of an integrative approach in identifying possible points of intervention, namely the activation of certain transcription factors that govern the organism's response.
A multi-treatment experimental system to examine photosynthetic differentiation in the maize leaf
Authors: Sawers Ruairidh JH , Liu Peng , Anufrikova Katya , Hwang JT Gene , Brutnell Thomas P 
Published: January 2007

AbstractBackgroundThe establishment of C4photosynthesis in maize is associated with differential accumulation of gene transcripts and proteins between bundle sheath and mesophyll photosynthetic cell types. We have physically separated photosynthetic cell types in the leaf blade to characterize differences in gene expression by microarray analysis. Additional control treatments were used to account for transcriptional changes induced by cell preparation treatments. To analyse these data, we have developed a statistical model to compare gene expression values derived from multiple, partially confounded, treatment groups.ResultsDifferential gene expression in the leaves of wild-type maize seedlings was characterized using the latest release of a maize long-oligonucleotide microarray produced by the Maize Array Project consortium. The complete data set is available through the project web site. Data is also available at the NCBI GEO website, series record GSE3890. Data was analysed with and without consideration of cell preparation associated stress.ConclusionEmpirical comparison of the two analyses suggested that consideration of stress helped to reduce the false identification of stress responsive transcripts as cell-type enriched. Using our model including a stress term, we identified 8% of features as differentially expressed between bundle sheath and mesophyll cell types under control of false discovery rate of 5%. An estimate of the overall proportion of differentially accumulating transcripts (1-π0) suggested that as many as 18% of the genes may be differentially expressed between B and M. The analytical model presented here is generally applicable to gene expression data and demonstrates the use of statistical elimination of confounding effects such as stress in the context of microarray analysis. We discuss the implications of the high degree of differential transcript accumulation observed with regard to both the establishment and engineering of the C4syndrome.