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Pre-cueing Effects on Perception, Attention, and Cognitive Penetrability

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889454600 Year: Pages: 98 DOI: 10.3389/978-2-88945-460-0 Language: English
Publisher: Frontiers Media SA
Subject: Science (General) --- Psychology
Added to DOAB on : 2018-11-16 17:17:57
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Attention has often been likened to spotlights and filters—devices that illuminate or screen out some inputs in favor of others. This largely passive conception of attention has been gradually replaced by a more dynamic and far-reaching process. We know that attentional processes augment neural processing at all levels, and in some cases, augmenting processing within the sense organs themselves. For example, cueing object features (e.g., instructing a subject to look at a screen for a red object) modulates prestimulus activity in the visual cortex.Far from being limited to space or basic features, such attention cueing can function in surprisingly flexible and complex ways: people can be cued to attend to various objects, properties, and semantic categories and such attention appears to directly involve perceptual mechanisms.Studies of spatial attention cues presented before stimulus presentation show early modulation of perceptual processing. This phenomenon refers to the enhancement of the baseline activity of neurons at all levels in the visual cortex that are tuned to the cued location, which is called attentional modulation of spontaneous activity. The spontaneous firing rates of neurons are increased when attention is shifted toward the location of an upcoming stimulus before its presentation. Evidence also suggests that through pre-cueing of object features, feature-based attention modulates prestimulus activity in the visual cortex. The effects of pre-stimulus feature attention act either as a preparatory activity to enhance the stimulus-evoked potentials within feature sensitive areas, or they act so as to modulate stimulus-locked transients.Both effects of pre-cueing reflect a change in background neural activity. They are called anticipatory effects established prior to the presentation of the stimulus. Thus, they do not modulate processing during stimulus viewing but bias the process before it starts via the increase in the base line firing rates; they rig-up perceptual processing without affecting it on-line.Moreover, recent work on perceptual processing emphasizes the role of brain as a predictive tool. To perceive is to use what you know to explain away the sensory signal across multiple spatial and temporal scales. Perception aims to enable perceivers to interact with their environment successfully. Success relies on inferring or predicting correctly (or nearly so) the nature of the source of the incoming signal from the signal itself, an inference that may well be Bayesian.Current research sheds light on the role of attention in inferring the identities of the distal objects. Attention within late vision contributes to testing hypotheses concerning the putative distal causes of the sensory data encoded in the lower neuronal assemblies in the visual processing hierarchy. This testing assumes the form of matching predictions, made on the basis of an hypothesis, about the sensory information that the lower levels should encode assuming that the hypothesis is correct, with the current, actual sensory information encoded at the lower levels. To this aim, attention enhances the activity of neurons in the cortical regions that encode the stimuli that most likely contain information relevant to the testing of the hypothesis.In this Research Topic we aim to answer two related questions: First, what are the differences between this sort of pre-cueing effects and top-down cognitive influences on perception, and, in general, how do such attentional cuing effects relate to the broader literature on top-down influences on perception? Second, given that attention appears to change perceptual processing and that a form of attention, namely, cognitively-driven (or endogenous, or sustained) attention is a cognitive process, does attentional modulation through pre-cueing constitute cognitive penetrability of perception? Addressing these two questions will shed light on the theoretical underpinnings of cognitive penetrability and the nature of perceptual processing.

Ways to improve tumor uptake and penetration of drugs into solid tumors

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889193509 Year: Pages: 129 DOI: 10.3389/978-2-88919-350-9 Language: English
Publisher: Frontiers Media SA
Subject: Oncology --- Medicine (General) --- Therapeutics --- Science (General)
Added to DOAB on : 2016-03-10 08:14:32
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The main scope of this topic is to give an update on pharmacologic and non-pharmacologic approaches to enhance uptake and penetration of cancer drugs into tumors. Inadequate accumulation of drugs in tumors has emerged over the last decade as one of the main problems underlying therapeutic failure and drug resistance in the treatment of cancer. Insufficient drug uptake and penetration is causally related to the abnormal tumor architecture. Thus, poor vascularization, increased resistance to blood flow and impaired blood supply represent a first obstacle to the delivery of antitumor drugs to tumor tissue. Decreased or even inverted transvascular pressure gradients compromise convective delivery of drugs. Eventually, an abnormal extracellular matrix offers increased frictional resistance to tumor drug penetration. Abnormal tumor architecture also changes the biology of tumor cells, which contributes to drug resistance through several different mechanisms. The variability in vessel location and structure can make many areas of the tumor hypoxic, which causes the tumor cells to become quiescent and thereby resistant to many antitumor drugs. In addition, the abnormally long distance of part of the tumor cell population from blood vessels provides a challenge to delivering cancer drugs to these cells. We have recently proposed additional mechanisms of tumor drug resistance, which are also related to abnormal tumor architecture. First, increased interstitial fluid pressure can by itself induce drug resistance through the induction of resistance-promoting paracrine factors. Second, the interaction of drug molecules with vessel- proximal tumor cell layers may also induce the release of these factors, which can spread throughout the cancer, and induce drug resistance in tumor cells distant from blood vessels. As can be seen, abnormal tumor architecture, inadequate drug accumulation and tumor drug resistance are tightly linked phenomena, suggesting the need to normalize the tumor architecture, including blood vessels, and/or increase the accumulation of cancer drugs in tumors in order to increase therapeutic effects. Indeed, several classes of drugs (that we refer to as promoter drugs) have been described, that promote tumor uptake and penetration of antitumor drugs, including those that are vasoactive, modify the barrier function of tumor vessels, debulk tumor cells, and overcome intercellular and stromal barriers. In addition, also non-pharmacologic approaches have been described that enhance tumor accumulation of effector drugs (e.g. convection-enhanced delivery, hyperthermia, etc.). Some drugs that have already received regulatory approval (e.g. the anti-VEGF antibody bevacizumab) exert antitumor effects at least in part through normalization of the tumor vasculature and enhancement of the accumulation of effector drugs. Other drugs, acting through different mechanisms of action, are now in clinical development (e.g. NGR-TNF in phase II/III studies) and others are about to enter clinical investigation (e.g. JO-1).

Earth Observation, Remote Sensing and Geoscientific Ground Investigations for Archaeological and Heritage Research

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ISBN: 9783039211937 / 9783039211944 Year: Pages: 304 DOI: 10.3390/books978-3-03921-194-4 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Science (General)
Added to DOAB on : 2019-08-28 11:21:27
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This book collects 15 papers written by renowned scholars from across the globe that showcase the forefront research in Earth observation (EO), remote sensing (RS), and geoscientific ground investigations to study archaeological records and cultural heritage.Archaeologists, anthropologists, geographers, remote sensing, and archaeometry experts share their methodologies relying on a wealth of techniques and data including, but not limited to: very high resolution satellite images from optical and radar space-borne sensors, air-borne surveys, geographic information systems (GIS), archaeological fieldwork, and historical maps.A couple of the contributions highlight the value of noninvasive and nondestructive laboratory analyses (e.g., neutron diffraction) to reconstruct ancient manufacturing technologies, and of geological ground investigations to corroborate hypotheses of historical events that shaped cultural landscapes.Case studies encompass famous UNESCO World Heritage Sites (e.g., the Nasca Lines in Peru), remote and yet-to-discover archaeological areas in tropical forests in central America, European countries, south Asian changing landscapes, and environments which are arid nowadays but were probably full of woody vegetation in the past.Finally, the reader can learn about the state-of-the-art of education initiatives to train site managers in the use of space technologies in support of their activities, and can understand the legal aspects involved in the application of EO and RS to address current challenges of African heritage preservation.

Keywords

analytic hierarchy process (AHP) --- archaeology --- predictive model --- tumuli --- remote sensing --- multi-criteria --- Saharan Morocco --- airborne laser scanning --- orthophotographs --- archaeological survey --- field reconnaissance --- Arran --- national archaeological mapping programme --- synthetic aperture radar --- subsurface imaging --- microwave penetration --- archaeology --- arid environments --- remote sensing --- Oman --- e-learning --- Earth observation --- education --- capacity development --- cultural and natural heritage --- UNESCO --- photogrammetry --- RPAS --- UAV --- Peru --- geoglyph Pista --- mapping --- drones --- remote sensing --- free satellite imagery --- GoogleEarth --- Bing Maps --- archaeological fieldwork --- arid environments --- basalt desert --- landscape accessibility --- Harra --- Jordan --- archaeological landscapes --- settlements --- historical maps --- Survey of India --- Archaeological Survey of India --- heritage --- colonial studies --- remote sensing --- historical landscapes --- landscape archaeology --- settlements --- colonial studies --- river morphology --- Indus --- floods --- remote sensing --- satellite --- Sentinel-2 --- surface survey --- Roman archaeology --- Sumerian pottery --- neutron techniques --- neutron diffraction --- chemometric analysis --- Mega El Niño --- pampa of Nazca --- Cuenca Pisco --- Rio Grande de Nazca --- grain-size --- volcaniclastic layer --- stratigraphy --- petrography --- Lidar --- GIS --- Mesoamerica --- Archaeology --- Caves --- Landscape --- Ritual --- Visualization --- Maya --- Belize --- Sacred --- automated detection --- OBIA --- LiDAR --- Difference Map --- field monument --- Burial Mound --- Motte-and-Bailey castle --- Ridge and Furrow --- space law --- disaster and conservation management --- Geographic Information System (GIS) --- international boundaries --- Africa --- Cameroon-Nigeria Mixed Commission --- satellite imagery --- Boundary Demarcation --- international law --- relict boundaries --- Earth Observation --- remote sensing --- optical --- SAR --- drone --- airborne LiDAR --- GIS --- OBIA --- neutron diffraction --- archaeological prospection --- pattern recognition --- archaeometry --- geological mapping

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