27 resultados para Remapping


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The body is represented in the brain at levels that incorporate multisensory information. This thesis focused on interactions between vision and cutaneous sensations (i.e., touch and pain). Experiment 1 revealed that there are partially dissociable pathways for visual enhancement of touch (VET) depending upon whether one sees one’s own body or the body of another person. This indicates that VET, a seeming low-level effect on spatial tactile acuity, is actually sensitive to body identity. Experiments 2-4 explored the effect of viewing one’s own body on pain perception. They demonstrated that viewing the body biases pain intensity judgments irrespective of actual stimulus intensity, and, more importantly, reduces the discriminative capacities of the nociceptive pathway encoding noxious stimulus intensity. The latter effect only occurs if the pain-inducing event itself is not visible, suggesting that viewing the body alone and viewing a stimulus event on the body have distinct effects on cutaneous sensations. Experiment 5 replicated an enhancement of visual remapping of touch (VRT) when viewing fearful human faces being touched, and further demonstrated that VRT does not occur for observed touch on non-human faces, even fearful ones. This suggests that the facial expressions of non-human animals may not be simulated within the somatosensory system of the human observer in the same way that the facial expressions of other humans are. Finally, Experiment 6 examined the enfacement illusion, in which synchronous visuo-tactile inputs cause another’s face to be assimilated into the mental self-face representation. The strength of enfacement was not affected by the other’s facial expression, supporting an asymmetric relationship between processing of facial identity and facial expressions. Together, these studies indicate that multisensory representations of the body in the brain link low-level perceptual processes with the perception of emotional cues and body/face identity, and interact in complex ways depending upon contextual factors.

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Subfields of the hippocampus display differential dynamics in processing a spatial environment, especially when changes are introduced to the environment. Specifically, when familiar cues in the environment are spatially rearranged, place cells in the CA3 subfield tend to rotate with a particular set of cues (e.g., proximal cues), maintaining a coherent spatial representation. Place cells in CA1, in contrast, display discordant behaviors (e.g., rotating with different sets of cues or remapping) in the same condition. In addition, on average, CA3 place cells shift their firing locations (measured by the center of mass, or COM) backward over time when the animal encounters the changed environment for the first time, but not after that first experience. However, CA1 displays an opposite pattern, in which place cells exhibit the backward COM-shift only from the second day of experience, but not on the first day. Here, we examined the relationship between the environment-representing behavior (i.e., rotation vs. remapping) and the COM-shift of place fields in CA1 and CA3. Both in CA1 and CA3, the backward (as well as forward) COM-shift phenomena occurred regardless of the rotating versus remapping of the place cell. The differential, daily time course of the onset/offset of backward COM-shift in the cue-altered environment in CA1 and CA3 (on day 1 in CA1 and from day 2 onward in CA3) stems from different population dynamics between the subfields. The results suggest that heterogeneous, complex plasticity mechanisms underlie the environment-representating behavior (i.e., rotate/remap) and the COM-shifting behavior of the place cell.

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Cells in adult primary visual cortex are capable of integrating information over much larger portions of the visual field than was originally thought. Moreover, their receptive field properties can be altered by the context within which local features are presented and by changes in visual experience. The substrate for both spatial integration and cortical plasticity is likely to be found in a plexus of long-range horizontal connections, formed by cortical pyramidal cells, which link cells within each cortical area over distances of 6-8 mm. The relationship between horizontal connections and cortical functional architecture suggests a role in visual segmentation and spatial integration. The distribution of lateral interactions within striate cortex was visualized with optical recording, and their functional consequences were explored by using comparable stimuli in human psychophysical experiments and in recordings from alert monkeys. They may represent the substrate for perceptual phenomena such as illusory contours, surface fill-in, and contour saliency. The dynamic nature of receptive field properties and cortical architecture has been seen over time scales ranging from seconds to months. One can induce a remapping of the topography of visual cortex by making focal binocular retinal lesions. Shorter-term plasticity of cortical receptive fields was observed following brief periods of visual stimulation. The mechanisms involved entailed, for the short-term changes, altering the effectiveness of existing cortical connections, and for the long-term changes, sprouting of axon collaterals and synaptogenesis. The mutability of cortical function implies a continual process of calibration and normalization of the perception of visual attributes that is dependent on sensory experience throughout adulthood and might further represent the mechanism of perceptual learning.

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The article explores the possibilities of formalizing and explaining the mechanisms that support spatial and social perspective alignment sustained over the duration of a social interaction. The basic proposed principle is that in social contexts the mechanisms for sensorimotor transformations and multisensory integration (learn to) incorporate information relative to the other actor(s), similar to the "re-calibration" of visual receptive fields in response to repeated tool use. This process aligns or merges the co-actors' spatial representations and creates a "Shared Action Space" (SAS) supporting key computations of social interactions and joint actions; for example, the remapping between the coordinate systems and frames of reference of the co-actors, including perspective taking, the sensorimotor transformations required for lifting jointly an object, and the predictions of the sensory effects of such joint action. The social re-calibration is proposed to be based on common basis function maps (BFMs) and could constitute an optimal solution to sensorimotor transformation and multisensory integration in joint action or more in general social interaction contexts. However, certain situations such as discrepant postural and viewpoint alignment and associated differences in perspectives between the co-actors could constrain the process quite differently. We discuss how alignment is achieved in the first place, and how it is maintained over time, providing a taxonomy of various forms and mechanisms of space alignment and overlap based, for instance, on automaticity vs. control of the transformations between the two agents. Finally, we discuss the link between low-level mechanisms for the sharing of space and high-level mechanisms for the sharing of cognitive representations. © 2013 Pezzulo, Iodice, Ferraina and Kessler.

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This article builds theory at the intersection of ecological sustainability and strategic management literature—specifically, in relation to dynamic capabilities literature. By combining industrial organization economics–based, resource-based, and dynamic capability–based views, it is possible to develop a better understanding of the strategies that businesses may follow, depending on their managers’ assumptions about ecological sustainability. To develop innovative strategies for ecological sustainability, the dynamic capabilities framework needs to be extended. In particular, the sensing–seizing–maintaining competitiveness framework should operate not only within the boundaries of a business ecosystem but in relation to global biophysical ecosystems; in addition, two more dynamic capabilities should be added, namely, remapping and reaping. This framework can explicate core managerial beliefs about ecological sustainability. Finally, this approach offers opportunities for managers and academics to identify, categorize, and exploit business strategies for ecological sustainability.

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The present study comparatively examined the socio-political and economic transformation of the indigenous Sámi in Sweden and the Indian American in the United States of America occurring first as a consequence of colonization and later as a product of interaction with the modern territorial and industrial state, from approximately 1500 to 1900. The first colonial encounters of the Europeans with these autochthonous populations ultimately created an imagery of the exotic Other and of the noble savage. Despite these disparaging representations, the cross-cultural settings in which these interactions took place also produced the hybrid communities and syncretic life that allowed levels of cultural accommodation, autonomous space, and indigenous agency to emerge. By the nineteenth century, however, the modern territorial and industrial state rearranges the dynamics and reaches of power across a redefined territorial sovereign space, consequently, remapping belongingness and identity. In this context, the status of indigenous peoples, as in the case of Sámi and of Indian Americans, began to change at par with industrialization and with modernity. At this point in time, indigenous populations became a hindrance to be dealt with the legal re-codification of Indigenousness into a vacuumed limbo of disenfranchisement. It is, thus, the modern territorial and industrial state that re-creates the exotic into an indigenous Other. The present research showed how the initial interaction between indigenous and Europeans changed with the emergence of the modern state, demonstrating that the nineteenth century, with its fundamental impulses of industrialism and modernity, not only excluded and marginalized indigenous populations because they were considered unfit to join modern society, it also re-conceptualized indigenous identity into a constructed authenticity.

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This thesis focuses on Chinese non-commercial animated films produced from 1949 to date, with the aim of remapping and reframing Chinese animation in the light of existing theories, critiques, and frameworks drawn from studies in animation, film, and screen media. I suggest that Chinese animation has experienced three aesthetic transformations since 1949, primarily influenced by traditional Chinese culture, by Western modernist art and literature and, most recently, by postmodernism, respectively. Thus, the research traces and thoroughly investigates these three distinctive phases of Chinese animation in chronological order, from the classical period (1950s– 1980s) to modernism (1980s–2000s) and postmodernism (after 2000s). More in detail, I first rethink and re-evaluate the success of classical Chinese animation and the Chinese school of animation and, at the same time, I explore the influence of the political situation of the time on Chinese animation. Through careful analysis of A Da (1934–87) and other Chinese animators’ practices and theory, then, I argue that a remarkable modernist transformation took place in Chinese animation between the 1980s and 2000s, mainly driven by Western modernism and the Chinese “cultural fever” movement. Finally, through a discussion of the latest non-commercial animations produced after 2005, and especially those of Bu Hua (1973– ), for the first time I classify and theorize contemporary Chinese animations within a postmodern framework. By reframing existing views and broadening the scope of the analysis to encompass new areas and frameworks, this thesis aims to provide the reader with a comprehensive and systematic understanding of post-1949 Chinese animation and to offer an original contribute to scholarship, also working as a starting point for further research in this area.

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Moving through a stable, three-dimensional world is a hallmark of our motor and perceptual experience. This stability is constantly being challenged by movements of the eyes and head, inducing retinal blur and retino-spatial misalignments for which the brain must compensate. To do so, the brain must account for eye and head kinematics to transform two-dimensional retinal input into the reference frame necessary for movement or perception. The four studies in this thesis used both computational and psychophysical approaches to investigate several aspects of this reference frame transformation. In the first study, we examined the neural mechanism underlying the visuomotor transformation for smooth pursuit using a feedforward neural network model. After training, the model performed the general, three-dimensional transformation using gain modulation. This gave mechanistic significance to gain modulation observed in cortical pursuit areas while also providing several testable hypotheses for future electrophysiological work. In the second study, we asked how anticipatory pursuit, which is driven by memorized signals, accounts for eye and head geometry using a novel head-roll updating paradigm. We showed that the velocity memory driving anticipatory smooth pursuit relies on retinal signals, but is updated for the current head orientation. In the third study, we asked how forcing retinal motion to undergo a reference frame transformation influences perceptual decision making. We found that simply rolling one's head impairs perceptual decision making in a way captured by stochastic reference frame transformations. In the final study, we asked how torsional shifts of the retinal projection occurring with almost every eye movement influence orientation perception across saccades. We found a pre-saccadic, predictive remapping consistent with maintaining a purely retinal (but spatially inaccurate) orientation perception throughout the movement. Together these studies suggest that, despite their spatial inaccuracy, retinal signals play a surprisingly large role in our seamless visual experience. This work therefore represents a significant advance in our understanding of how the brain performs one of its most fundamental functions.

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Este estudo analiza como Manuel Rivas aproveita a ambigüidade do concepto de estereotipo para crear una identidade cultural galega. En Unha espía no Reino de Galicia (2004), Rivas propón que a imaxe paródica do galego e o conxunto de trazos estereotipados que se lle asignan non son un elemento alleo a cultura galega, senón que é un trazo integral da dialéctica da súa identidade nacional. Desta maneira, ó feito diferencial galego, ademais da lingua, a unidade territorial, o celtismo, ou a emigración, habería que engadir a capacidade do galego de parodiar o seu propio discurso nacional.

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A large class of computational problems are characterised by frequent synchronisation, and computational requirements which change as a function of time. When such a problem is solved on a message passing multiprocessor machine [5], the combination of these characteristics leads to system performance which deteriorate in time. As the communication performance of parallel hardware steadily improves so load balance becomes a dominant factor in obtaining high parallel efficiency. Performance can be improved with periodic redistribution of computational load; however, redistribution can sometimes be very costly. We study the issue of deciding when to invoke a global load re-balancing mechanism. Such a decision policy must actively weigh the costs of remapping against the performance benefits, and should be general enough to apply automatically to a wide range of computations. This paper discusses a generic strategy for Dynamic Load Balancing (DLB) in unstructured mesh computational mechanics applications. The strategy is intended to handle varying levels of load changes throughout the run. The major issues involved in a generic dynamic load balancing scheme will be investigated together with techniques to automate the implementation of a dynamic load balancing mechanism within the Computer Aided Parallelisation Tools (CAPTools) environment, which is a semi-automatic tool for parallelisation of mesh based FORTRAN codes.

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The Elfas, Ahlsburg, and Salzderhelden overthrusts have been considered for a long time to be halotectonic structures caused by diapiric rise of Zechstein salt into thrust planes and other zones of weakness in the overlying rocks. Much of the Markoldendorf syncline between the overthrusts is covered by Quaternary deposits. The structure of the syncline and its western and southern boundaries were mapped with the help of many boreholes and micropalaeontological dating during remapping of the 1 : 25 000 geological sheet 4124 (Dassel). The Ahlsburg overthrust has now been shown to continue to the NW and to lead into the Lüthorst graben, which truncates the syncline in the west and passes into the crestal fault of the Elfas anticline. Figure 6 shows the NW-SE trending faults bounding three blocks which, according to seismic interpretation (Geotectonic Atlas 1996), have moved several times, in some areas in opposite senses. The NNE-SSW-trending grabens act as hinges, separating the NW-SE faults into sections that have undergone different movement.

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The present study comparatively examined the socio-political and economic transformation of the indigenous Sámi in Sweden and the Indian American in the United States of America occurring first as a consequence of colonization and later as a product of interaction with the modern territorial and industrial state, from approximately 1500 to 1900. ^ The first colonial encounters of the Europeans with these autochthonous populations ultimately created an imagery of the exotic Other and of the noble savage. Despite these disparaging representations, the cross-cultural settings in which these interactions took place also produced the hybrid communities and syncretic life that allowed levels of cultural accommodation, autonomous space, and indigenous agency to emerge. By the nineteenth century, however, the modern territorial and industrial state rearranges the dynamics and reaches of power across a redefined territorial sovereign space, consequently, remapping belongingness and identity. In this context, the status of indigenous peoples, as in the case of Sámi and of Indian Americans, began to change at par with industrialization and with modernity. At this point in time, indigenous populations became a hindrance to be dealt with the legal re-codification of Indigenousness into a vacuumed limbo of disenfranchisement. It is, thus, the modern territorial and industrial state that re-creates the exotic into an indigenous Other. ^ The present research showed how the initial interaction between indigenous and Europeans changed with the emergence of the modern state, demonstrating that the nineteenth century, with its fundamental impulses of industrialism and modernity, not only excluded and marginalized indigenous populations because they were considered unfit to join modern society, it also re-conceptualized indigenous identity into a constructed authenticity.^