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31.
Twelve patients with Alzheimer's disease (AD) and 15 healthy elderly control subjects were shown sets of luminance-defined letters, texture-defined letters, luminance-defined squares, and texture-defined squares. They were asked to name the letters or point to the target square on each page. The stimuli were graded into four levels of difficulty based on the amount of contrast between the figure and the background. Performance was measured in terms of the maximum level of difficulty at which the participant correctly identified or located the three figures. Contrary to expectations, no significant difference was found between the performance of AD patients and control subjects on texture discrimination tasks vs. luminance discrimination tasks. However, results indicate that AD patients are impaired in performing a task requiring them to locate a texture-defined target of known shape in a noisy background field. By contrast, AD patients show no significant deficit in a task requiring them to locate a texture-defined shape in a known location. This argues that the observed deficit in the location task is not due to a failure in the system that discriminates target texture from background texture (since both location and identification tasks require the same textural discriminations), but rather to an impairment of the system responsible for "finding things" (i.e., locating known targets at unknown locations). This observation suggests that AD patients may suffer selective damage to the dorsal "Where" pathway, which is responsible for localizing objects in space. 相似文献
32.
Devan BD Goad EH Petri HL Antoniadis EA Hong NS Ko CH Leblanc L Lebovic SS Lo Q Ralph MR McDonald RJ 《Neurobiology of learning and memory》2001,75(1):51-62
It is thought that circadian rhythms may influence learning and memory processes. However, research supporting this view does not dissociate a mnemonic impairment from other performance deficits. Furthermore, published reports do not specify the type of memory system influenced by the circadian system. The present study assessed the effects of phase shifting on acquisition and expression of place navigation in the water maze, a task sensitive to hippocampal dysfunction. The results showed that phase-shifting circadian rhythms in rats impaired the expression of place information on a retention test but not initial acquisition or encoding of place information. These results suggest that disruption of circadian rhythms may impair consolidation of previously encoded hippocampal place information. 相似文献
33.
In this study, cross-cultural differences in cognitive test scores are hypothesized to depend on a test's cultural complexity (Cultural Complexity Hypothesis: CCH), here conceptualized as its content familiarity, rather than on its cognitive complexity (Spearman's Hypothesis: SH). The content familiarity of tests assessing short-term memory, attention, working memory, and figural and verbal fluid reasoning, was manipulated by constructing test versions with an item content derived from either Afrikaans or Tswana culture in South Africa. Both test versions were administered to children of both cultures. The sample consisted of 161 urban Afrikaans, 181 urban, and 159 rural Tswana children (Mage = 9.37 years). Children generally performed best on the test version that was designed for their own group, particularly on the cognitively and culturally complex working memory and figural fluid reasoning tests. This relation between content familiarity and cognitive test performance supports CCH and disconfirms SH. 相似文献
34.
Counselors are in ideal positions to help change attitudes toward viewing menopause as a time of positive change, rather than a time of psychological distress. Following definitions and a review of historical, sociological, psychological, and attitudinal factors that account for negative responses associated with menopause, recommendations for counselor interventions are proposed. 相似文献
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Semi-Post algebras have been introduced and investigated in [6]. This paper is devoted to semi-Post subalgebras and homomorphisms. Characterization of semi-Post subalgebras and homomorphisms, relationships between subalgebras and homomorphisms of semi-Post algebras and of generalized Post algebras are examined. 相似文献
37.
Brona S. O'dowd Wei Q. Zhao Kim T. Ng Stephen R. Robinson 《Neurobiology of learning and memory》1997,67(3):197-206
The cellular expression of S-100β protein is upregulated in Alzheimer's disease and in Down's syndrome, and this protein has been implicated in memory-related processes in laboratory animals. However, the possibility that the α subunit of S-100 is also involved in memory has not yet been examined. In the present study, day-old black Australorp white Leghorn cockerel chicks (Gallus domesticus) received injections of monoclonal antisera to S-100α (1:50) or S-100β (1:500) into each hemisphere immediately after training on a one-trial passive avoidance task. The chicks displayed significantly lower retention levels than control birds that had been injected with antisera to carbonic anhydrase, or with saline (p< .01). S-100α antisera had an amnestic effect when injected between 0 and 20 min after training, with memory deficits occurring from 30 min postlearning, at the point of transition between the A and the B phases of the Gibbs-Ng intermediate memory stage. By contrast, the S-100β antisera needed to be injected either 5 min before or immediately after training and produced amnesia 10 min earlier, at the start of the A phase of the intermediate memory stage. We conclude that the two subunits of the S-100 protein are required at different points in the sequence of events leading to the consolidation of passive avoidance memory. 相似文献
38.
The aim of this study was to determine whether gender moderates the relationship between spirituality and psychological well-being. A secondary data analysis based on a cross sectional survey was implemented. A convenience sample of 508 participants (males = 143, females = 365; age range 18–65 with 66% in the 18–25 category) from the North-West Province of South Africa completed questionnaires on spirituality and psychological well-being after informed consent was obtained. Findings show that gender moderates the relationship between spirituality and psychological well-being. This moderation effect was stronger in the case of existential well-being rather than religious well-being as components of spiritual wellbeing, and also stronger in one of the sub-groups. Future studies may explore the role of contextual factors such as cultural orientation and other socio-demographic variables in this moderation effect, as well as gender based perceptions and practices of spirituality with a view to facilitate gender sensitive psychological well-being programmes. 相似文献
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As part of a longitudinal study, the Cognitive Triad Inventory for Children (CTI-C; N. J. Kaslow, K. D. Stark, B. Printz, R. Livingston, & S. L. Tsai, 1992) as well as other measures of cognitive style and depressive symptoms were administered annually to 3 cohorts of children starting in Grades 2, 4, and 6. Developmentally based analyses revealed 4 things: (a) The factor structure of the CTI-C changed over the course of middle childhood and then stabilized in early adolescence; (b) the CTI-C correlated significantly with measures of depression, self-perceived competence, self-worth, perceived controllability, and perceived contingency, but not with measures of attributional style; (c) 1-year stability correlations increased substantially from Grade 2 to Grade 8; and (d) the CTI-C did not generally predict self-reported depressive symptoms 1 year later. Implications emerge regarding developmental changes in the structure of children's depressive cognitions. 相似文献