897 resultados para memory and cognition
Resumo:
The apolipoprotein E (APOE) epsilon4 allele is the major genetic risk factor for Alzheimer's disease, but an APOE effect on memory performance and memory-related neurophysiology in young, healthy subjects is unknown. We found an association of APOE epsilon4 with better episodic memory compared with APOE epsilon2 and epsilon3 in 340 young, healthy persons. Neuroimaging was performed in a subset of 34 memory-matched individuals to study genetic effects on memory-related brain activity independently of differential performance. E4 carriers decreased brain activity over 3 learning runs, whereas epsilon2 and epsilon3 carriers increased activity. This smaller neural investment of epsilon4 carriers into learning reappeared during retrieval: epsilon4 carriers exhibited reduced retrieval-related activity with equal retrieval performance. APOE isoforms had no differential effects on cognitive measures other than memory, brain volumes, and brain activity related to working memory. We suggest that APOE epsilon4 is associated with good episodic memory and an economic use of memory-related neural resources in young, healthy humans.
Resumo:
Stress is a strong modulator of memory function. However, memory is not a unitary process and stress seems to exert different effects depending on the memory type under study. Here, we explored the impact of social stress on different aspects of human memory, including tests for explicit memory and working memory (for neutral materials), as well as implicit memory (perceptual priming, contextual priming and classical conditioning for emotional stimuli). A total of 35 young adult male students were randomly assigned to either the stress or the control group, with stress being induced by the Trier Social Stress Test (TSST). Salivary cortisol levels were assessed repeatedly throughout the experiment to validate stress effects. The results support previous evidence indicating complex effects of stress on different types of memory: A pronounced working memory deficit was associated with exposure to stress. No performance differences between groups of stressed and unstressed subjects were observed in verbal explicit memory (but note that learning and recall took place within 1 h and immediately following stress) or in implicit memory for neutral stimuli. Stress enhanced classical conditioning for negative but not positive stimuli. In addition, stress improved spatial explicit memory. These results reinforce the view that acute stress can be highly disruptive for working memory processing. They provide new evidence for the facilitating effects of stress on implicit memory for negative emotional materials. Our findings are discussed with respect to their potential relevance for psychiatric disorders, such as post traumatic stress disorder.
Resumo:
More than a century ago, Galton and Spearman suggested that there was a functional relationship between sensory discrimination ability and intelligence. Studies have since been able to confirm a close relationship between general discrimination ability (GDA) and IQ. The aim of the present study was to assess whether this strong relationship between GDA and IQ could be due to working memory (WM) demands of GDA tasks. A sample of 140 children (seventy 9-year-olds and seventy 11-year-olds) was studied. Results showed that there was a significant overlap between WM, GDA and fluid intelligence. Furthermore, results also revealed that WM could not explain the relationship between GDA and fluid intelligence as such, but that it acted as a bottleneck of information processing, limiting the influence of GDA on the prediction of fluid intelligence. Specifically, GDA's influence on the prediction of intelligence was only visible when WM capacity was above a certain level.
Resumo:
This investigation examined the clonal dynamics of B-cell expression and evaluated the role of idiotype network interactions in shaping the expressed secondary B-cell repertoire. Three interrelated experimental approaches were applied. The first approach was designed to distinguish between regulatory influences controlled by the major histocompatibility complex (MHC) and regulatory influences controlled by non-MHC factors including the idiotype network. This approach consisted of studies on the clonal dynamics and heterogeneity of the expressed IgG antibody repertoire of BALB/c mice. The second approach involved the analysis of the clonal dynamics of antibody responses of outbred rabbits. This analysis was coupled with studies to detect the occurrence and activity of constituents of the idiotype network. In the third approach the transfer of rabbit lymphocytes from immunized donors to MHC matched naive recipients was used to examine the effects of recipient non-MHC immunoregulatory influences on the expression of donor memory B-cells. Although many memory B cells were unaffected by non-MHC influences, these data show that non-MHC immunoregulatory influences can affect the expression of B-cells in the secondary response of inbred mice and outbred rabbits. The results also indicate that most IgG antibody responses are heterogeneous and are characterized by a stable group of dominant clonotypes. Clonal dominance and B-cell memory were found to be established early in an immune response. The expression of B memory clones appeared to be favored over the expression of virgin B cells. The injection of anti-tetanus antibody induced the antigen independent production of anti-tetanus antibody, probably through idiotypic mechanisms. These results demonstrate that both antibody and antigen can affect the expressed B-ceIl repertoire. Thus, idiotypic interactions are capable of influencing the expression of B-cells and these findings support the existence and function of an idiotype network with strong immunoregulatory potential. ^
Resumo:
This article analyses narrations of German memories in relation to the incorporation of Islam into Germany. Memory narratives are not approached from the angle of identity, but as part of the continuous business of rationalizing politics inside and beyond the state. The citational use of narratives authorizes interventions in the process of government by constituting its objects, determining the means and aims of government and defining its authority. Narratives are a governmental practice, i.e. they connect politics narrowly defined with individual conduct, since narratives allow determination of a social context and what constitutes adequate behaviour within it. In this way, they help to orient practices of freedom. Acts such as the cultivating of an ethics of interreligious competition, involvement in specific forms of dialogue, or activism against Islamophobia and anti-Semitism derive meaning in part through such narratives, while simultaneously contributing new meaning.
Resumo:
The multi-layered enactment of a national past in music has been strongly intertwined with the usage of mythological elements. Having often been compiled as a coherent narrative during the emergence of the European nation-states (like the Finnish Kalevala), the mythological material has often been perceived as a form of historical truth and national justification. This focal role is also apparent in various music genres ranging from folk revival to metal in post-1989 Europe. Within the globalized context, however, local-national interpretations can collide with earlier nationalist appropriations. This complex and sometimes politically conflicting situation becomes particularly evident with groups falling back on symbols and narrations that had previously been employed by Nazi-Germany. While Nazi-Germany had, among others, tried replace the Christmas tradition with elements and songs from Germanic (and other) mythological sources, modern Neo-Nazi music groups often employ central mythological names (like Odin or Tyr) and iconic elements (like Vikings and warriors) in song lyrics and CD cover designs. However, while many covers and lyrics are legally forbidden in Germany, Scandinavian and Baltic groups (like the Faroese Viking metal group Tyr and the Latvian pagan metal band Skyforger) employ similar elements of Norse mythology, which are often combined with traditional material. Discussing selected case studies, this paper highlights central discursive points of colliding historical-national associations and individual interpretations of the mythological elements in musical contexts. How far can the material be disassociated from the earlier historical political usage and instrumentalization? Is this necessary ? And how can the specific global-local conflict points be approached by a theoretical framework ?
Resumo:
Studies revealing transfer effects of working memory (WM) training on non-trained cognitive performance of children hold promising implications for scholastic learning. However, the results of existing training studies are not consistent and provoke debates about the potential and limitations of cognitive enhancement. To examine the influence of individual differences on training outcomes is a promising approach for finding causes for such inconsistencies. In this study, we implemented WM training in an elementary school setting. The aim was to investigate near and far transfer effects on cognitive abilities and academic achievement and to examine the moderating effects of a dispositional and a regulative temperament factor, neuroticism and effortful control. Ninetynine second-graders were randomly assigned to 20 sessions of computer-based adaptiveWMtraining, computer-based reading training, or a no-contact control group. For the WM training group, our analyses reveal near transfer on a visual WM task, far transfer on a vocabulary task as a proxy for crystallized intelligence, and increased academic achievement in reading and math by trend. Considering individual differences in temperament, we found that effortful control predicts larger training mean and gain scores and that there is a moderation effect of both temperament factors on post-training improvement: WM training condition predicted higher post-training gains compared to both control conditions only in children with high effortful control or low neuroticism. Our results suggest that a short but intensive WM training program can enhance cognitive abilities in children, but that sufficient selfregulative abilities and emotional stability are necessary for WM training to be effective.
Resumo:
Background. At present, prostate cancer screening (PCS) guidelines require a discussion of risks, benefits, alternatives, and personal values, making decision aids an important tool to help convey information and to help clarify values. Objective: The overall goal of this study is to provide evidence of the reliability and validity of a PCS anxiety measure and the Decisional Conflict Scale (DCS). Methods. Using data from a randomized, controlled PCS decision aid trial that measured PCS anxiety at baseline and DCS at baseline (T0) and at two-weeks (T2), four psychometric properties were assessed: (1) internal consistency reliability, indicated by factor analysis intraclass correlations and Cronbach's α; (2) construct validity, indicated by patterns of Pearson correlations among subscales; (3) discriminant validity, indicated by the measure's ability to discriminate between undecided men and those with a definite screening intention; and (4) factor validity and invariance using confirmatory factor analyses (CFA). Results. The PCS anxiety measure had adequate internal consistency reliability and good construct and discriminant validity. CFAs indicated that the 3-factor model did not have adequate fit. CFAs for a general PCS anxiety measure and a PSA anxiety measure indicated adequate fit. The general PCS anxiety measure was invariant across clinics. The DCS had adequate internal consistency reliability except for the support subscale and had adequate discriminate validity. Good construct validity was found at the private clinic, but was only found for the feeling informed subscale at the public clinic. The traditional DCS did not have adequate fit at T0 or at T2. The alternative DCS had adequate fit at T0 but was not identified at T2. Factor loadings indicated that two subscales, feeling informed and feeling clear about values, were not distinct factors. Conclusions. Our general PCS anxiety measure can be used in PCS decision aid studies. The alternative DCS may be appropriate for men eligible for PCS. Implications: More emphasis needs to be placed on the development of PCS anxiety items relating to testing procedures. We recommend that the two DCS versions be validated in other samples of men eligible for PCS and in other health care decisions that involve uncertainty. ^