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951.
Visual cortical areas are involved in a variety of somatosensory tasks in the sighted, including tactile perception of two-dimensional patterns and motion, and haptic perception of three-dimensional objects. It is still unresolved whether visual imagery or modality-independent representations can better explain such cross-modal recruitment. However, these explanations are not necessarily in conflict with each other and might both be true, if imagery processes can access modality-independent representations. Greater visual cortical engagement in blind compared to sighted people is commonplace during language tasks, and also seems to occur during processing of tactile spatial information. Such engagement is even greater in the congenitally blind compared to the late blind, indicative of enhanced cross-modal plasticity during early development. At the other extreme, short-term visual deprivation of the normally sighted also leads to cross-modal plasticity. Altogether, the boundaries between sensory modalities appear to be flexible rather than immutable.  相似文献   
952.
A neurobiological theory of automaticity in perceptual categorization   总被引:3,自引:0,他引:3  
A biologically detailed computational model is described of how categorization judgments become automatic in tasks that depend on procedural learning. The model assumes 2 neural pathways from sensory association cortex to the premotor area that mediates response selection. A longer and slower path projects to the premotor area via the striatum, globus pallidus, and thalamus. A faster, purely cortical path projects directly to the premotor area. The model assumes that the subcortical path has greater neural plasticity because of a dopamine-mediated learning signal from the substantia nigra. In contrast, the cortical-cortical path learns more slowly via (dopamine independent) Hebbian learning. Because of its greater plasticity, early performance is dominated by the subcortical path, but the development of automaticity is characterized by a transfer of control to the faster cortical-cortical projection. The model, called SPEED (Subcortical Pathways Enable Expertise Development), includes differential equations that describe activation in the relevant brain areas and difference equations that describe the 2- and 3-factor learning. A variety of simulations are described, showing that the model accounts for some classic single-cell recording and behavioral results.  相似文献   
953.
Most body-image research has focused on the trait level of body-image evaluation, often neglecting the momentary fluctuations many people experience in everyday life. The present prospective study investigated whether theory-relevant body-image measures, perfectionistic self-presentation, and eating attitudes would predict average day-to-day body-image levels and their intra-individual variability. A convenience sample consisted of 121 women from two universities. In Phase 1 of the study, participants completed an online battery of selected body-image and personality questionnaires. In Phase 2, participants went online to complete the dependent measure, the Body Image States Scale, once per evening over 10 days. As hypothesized, more favorable body-image state levels were associated with less investment in appearance for self-worth, less body-image disturbance, fewer body-image cognitive distortions, less disturbed eating attitudes, and lower body mass. Moreover, greater day-to-day body-image variability was predicted by greater psychological investment in appearance, more body-image cognitive distortions, and higher perfectionistic self-presentation. Implications and future directions for research are discussed.  相似文献   
954.
TRAP-1 is a mitochondrial heat shock protein (HSP), recently identified in Saos-2 osteosarcoma cells adapted to mild oxidative stress induced by diethylmaleate (DEM). TRAP-1 mRNA expression is increased in DEM-adapted cells as well as in tumor cells resistant to 5-fluorouracil and to platin derivatives. Since a strong decrease of TRAP-1 protein levels, upon cisplatin treatment, is observed only in controls but not in the DEM-adapted counterpart, a possible role for this protein in the development of resistant phenotypes could be hypothesized. To characterize the protective role of TRAP-1 against oxidative stress and apoptosis, stable transfectants were generated and characterized for their response to different stress types. These stable clones expressing constitutively high TRAP-1 levels: (i) are more resistant to H2O2-induced DNA damage and to apoptosis by cisplatin; (ii) contain higher reduced glutathione (GSH) levels than control cells; and (iii) do not release the apoptosis-inducing factor into the nucleus upon cisplatin treatment. Furthermore, high TRAP-1 levels interfere with caspase 3 activation. These results confirm the anti-apoptotic role of TRAP-1, and suggest that increased expression of this mitochondrial HSP in DEM-adapted and chemoresistant cells could be part of a pro-survival signaling pathway aimed to evade toxic effects of oxidants and anticancer drugs.  相似文献   
955.
The authors provide a didactic treatment of nonlinear (categorical) principal components analysis (PCA). This method is the nonlinear equivalent of standard PCA and reduces the observed variables to a number of uncorrelated principal components. The most important advantages of nonlinear over linear PCA are that it incorporates nominal and ordinal variables and that it can handle and discover nonlinear relationships between variables. Also, nonlinear PCA can deal with variables at their appropriate measurement level; for example, it can treat Likert-type scales ordinally instead of numerically. Every observed value of a variable can be referred to as a category. While performing PCA, nonlinear PCA converts every category to a numeric value, in accordance with the variable's analysis level, using optimal quantification. The authors discuss how optimal quantification is carried out, what analysis levels are, which decisions have to be made when applying nonlinear PCA, and how the results can be interpreted. The strengths and limitations of the method are discussed. An example applying nonlinear PCA to empirical data using the program CATPCA (J. J. Meulman, W. J. Heiser, & SPSS, 2004) is provided.  相似文献   
956.
In a large, community-based sample of women (N = 750), the authors examined the nature of associations between dysfunctional attitudes and depression. Dysfunctional attitudes were evaluated both as a vulnerability factor for depression and as a consequence of depression. A link was found between past depression and baseline elevations in dysfunctional attitudes that was independent of current subsyndromal symptoms, but intensification of dysfunctional attitudes following prospectively evaluated episodes of depression (depressive "scarring") was not observed. Although baseline dysfunctional attitudes predicted an episode of major depression over 3 years of prospective study, this prediction, considered alone or in interaction with negative life events, was redundant with that offered by history of past depression. Further, no significant prediction was evident for the Dysfunctional Attitude Scale (A. N. Weissman & A. T. Beck, 1978) when the formerly depressed and never-depressed cohorts were considered separately. Implications for cognitive theories are discussed.  相似文献   
957.
The aim of the present study was to investigate whether the four facets of Hare's Psychopathy Checklist-Revised (PCL-R; Hare, 1991; Bolt, Hare, Vitale, & Newman, 2004) were related to physiological and cognitive mechanisms. Fifty-three male prisoners participated in this study. Physiological responses were measured as heart rate variability (HRV) and heart rate (HR). Cognitive functions were measured using a continuous performance test (CPT; California Computerized Assessment Package, Abbreviated version) and a working memory test (WMT); based on Baddeley & Hitch (1974). The regression analysis of the HRV revealed that the interpersonal facet explained most of the variance during baseline (28%), CPT (16%), and WMT (12%). This was also true for the HR data during baseline (28%), CPT (20%), WMT (10%), and recovery (13%). The antisocial facet explained 10% of the variance only during baseline. Subjects scoring high compared to low on the interpersonal facet also showed better cognitive functioning. The study suggests that the different facets were differently associated with both physiological and cognitive functions.  相似文献   
958.
An update is presented on the steady decline in the education and training of psychometricians, quantitative psychologists, and personality assessment psychologists in North America.  相似文献   
959.
This paper examines whether workplace characteristics, particularly resource availability and transformational leadership, moderate the association between openness to experience and organizational commitment. In Study 1, 205 employees completed a questionnaire that assessed their openness, organizational commitment, and perceived availability of resources at their organization. Openness reduced the extent to which individuals felt obliged to remain loyal to the organization, although this association diminished as resources became more accessible. In Study 2, 312 employees completed a similar questionnaire that also gauged the perceived leadership style of their supervisors. Transformational leadership amplified the positive relationship between openness and organizational commitment. These findings align with the proposition that individuals are more committed in work environments that facilitate the expression of their traits.  相似文献   
960.
MicroSKED     
MicroSKED has transferred the assets of SKED to a microprocessor. Designed around the 6502 microprocessor, MicroSKED contains an editor, compiler, and run-time system. The basic system has 512 words of user memory, 124 inputs, 4 outputs, a time-of-day clock, a keyboard, and a display. The projected cost of the system is $300. The system may be expanded. Differences between SKED and MicroSKED are examined.  相似文献   
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