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1.
Background
Using tools to act on non-food objects—for example, to make other tools—is considered to be a hallmark of human intelligence, and may have been a crucial step in our evolution. One form of this behaviour, ‘sequential tool use’, has been observed in a number of non-human primates and even in one bird, the New Caledonian crow (Corvus moneduloides). While sequential tool use has often been interpreted as evidence for advanced cognitive abilities, such as planning and analogical reasoning, the behaviour itself can be underpinned by a range of different cognitive mechanisms, which have never been explicitly examined. Here, we present experiments that not only demonstrate new tool-using capabilities in New Caledonian crows, but allow examination of the extent to which crows understand the physical interactions involved.Methodology/Principal Findings
In two experiments, we tested seven captive New Caledonian crows in six tasks requiring the use of up to three different tools in a sequence to retrieve food. Our study incorporated several novel features: (i) we tested crows on a three-tool problem (subjects were required to use a tool to retrieve a second tool, then use the second tool to retrieve a third one, and finally use the third one to reach for food); (ii) we presented tasks of different complexity in random rather than progressive order; (iii) we included a number of control conditions to test whether tool retrieval was goal-directed; and (iv) we manipulated the subjects'' pre-testing experience. Five subjects successfully used tools in a sequence (four from their first trial), and four subjects repeatedly solved the three-tool condition. Sequential tool use did not require, but was enhanced by, pre-training on each element in the sequence (‘chaining’), an explanation that could not be ruled out in earlier studies. By analyzing tool choice, tool swapping and improvement over time, we show that successful subjects did not use a random probing strategy. However, we find no firm evidence to support previous claims that sequential tool use demonstrates analogical reasoning or human-like planning.Conclusions/Significance
While the ability of subjects to use three tools in sequence reveals a competence beyond that observed in any other species, our study also emphasises the importance of parsimony in comparative cognitive science: seemingly intelligent behaviour can be achieved without the involvement of high-level mental faculties, and detailed analyses are necessary before accepting claims for complex cognitive abilities. 相似文献2.
Rationale
Khat consumption has increased during the last decades in Eastern Africa and has become a global phenomenon spreading to ethnic communities in the rest of the world, such as The Netherlands, United Kingdom, Canada, and the United States. Very little is known, however, about the relation between khat use and cognitive control functions in khat users.Objective
We studied whether khat use is associated with changes in working memory (WM) and cognitive flexibility, two central cognitive control functions.Methods
Khat users and khat-free controls were matched in terms of sex, ethnicity, age, alcohol and cannabis consumption, and IQ (Raven''s progressive matrices). Groups were tested on cognitive flexibility, as measured by a Global-Local task, and on WM using an N-back task.Result
Khat users performed significantly worse than controls on tasks tapping into cognitive flexibility as well as monitoring of information in WM.Conclusions
The present findings suggest that khat use impairs both cognitive flexibility and the updating of information in WM. The inability to monitor information in WM and to adjust behavior rapidly and flexibly may have repercussions for daily life activities. 相似文献3.
Background
The medial prefrontal cortex has been implicated in a variety of cognitive and executive processes such as decision making and working memory. The medial prefrontal cortex of rodents consists of several areas including the prelimbic and infralimbic cortex that are thought to be involved in different aspects of cognitive performance. Despite the distinct roles in cognitive behavior that have been attributed to prelimbic and infralimbic cortex, little is known about neuronal network functioning of these areas, and whether these networks show any interaction during fast network oscillations.Methodology/Principal Findings
Here we show that fast network oscillations in rat infralimbic cortex slices occur at higher frequencies and with higher power than oscillations in prelimbic cortex. The difference in oscillation frequency disappeared when prelimbic and infralimbic cortex were disconnected.Conclusions/Significance
Our data indicate that neuronal networks of prelimbic and infralimbic cortex can sustain fast network oscillations independent of each other, but suggest that neuronal networks of prelimbic and infralimbic cortex are interacting during these oscillations. 相似文献4.
Background and Aims
Germination and heterotrophic growth are crucial steps for stand establishment. Numerical experiments based on the modelling of these early stages in relation to major environmental factors at sowing were used as a powerful tool to browse the effects of the genetic diversity of Medicago truncatula, one of the model legume species, under a range of agronomic scenarios, and to highlight the most important plant parameters for emergence. To this end, the emergence of several genotypes of M. truncatula was simulated under a range of sowing conditions with a germination and emergence simulation model.Methods
After testing the predictive quality of the model by comparing simulations to field observations of several genotypes of M. truncatula, numerical experiments were performed under a wide range of environmental conditions (sowing dates × years × seedbed structure). Germination and emergence was simulated for a set of five genotypes previously parameterized and for two virtual genotypes engineered to maximize the potential effects of genetic diversity.Key Results
The simulation results gave an average value of 5–10 % difference in final emergence between genotypes, which was low, but the analysis underlined considerable inter-annual variation. The effects of parameters describing germination and emergence processes were quantified and ranked according to their contribution to the variation in emergence. Seedling non-emergence was mainly related to mechanical obstacles (40–50 %). More generally, plant parameters that accelerated the emergence time course significantly contributed to limiting the risk of soil surface crusting occurring before seedling emergence.Conclusions
The model-assisted analysis of the effects of genetic diversity demonstrated its usefulness in helping to identify the parameters which have most influence that could be improved by breeding programmes. These results should also enable a deeper analysis of the genetic determinism of the main plant parameters influencing emergence, using the genomic tools available for this model plant. 相似文献5.
Emmanuelle Kesse-Guyot Hélène Charreire Valentina A. Andreeva Mathilde Touvier Serge Hercberg Pilar Galan Jean-Michel Oppert 《PloS one》2012,7(10)
Background
The deleterious health effects of sedentary behaviors, independent of physical activity, are increasingly being recognized. However, associations with cognitive performance are not known.Purpose
To estimate the associations between different sedentary behaviors and cognitive performance in healthy older adults.Methods
Computer use, time spent watching television (TV), time spent reading and habitual physical activity levels were self-reported twice (in 2001 and 2007) by participants in the SUpplémentation en Vitamines et MinérauX (SU.VI.MAX and SU.VI.MAX2) study. Cognitive performance was assessed at follow-up (in 2007–2009) via a battery of 6 neuropsychological tests used to derive verbal memory and executive functioning scores. Analyses (ANCOVA) were performed among 1425 men and 1154 women aged 65.6±4.5 at the time of the neuropsychological evaluation. We estimated mean differences with 95% confidence intervals (95%CI) in cognitive performance across categories of each type of sedentary behavior.Results
In multivariable cross-sectional models, compared to non-users, participants using the computer for >1 h/day displayed better verbal memory (mean difference = 1.86; 95%CI: 0.95, 2.77) and executive functioning (mean difference = 2.15; 95%CI: 1.22, 3.08). A negative association was also observed between TV viewing and executive functioning. Additionally, participants who increased their computer use by more than 30 min between 2001 and 2007 showed better performance on both verbal memory (mean difference = 1.41; 95%CI: 0.55, 2.27) and executive functioning (mean difference = 1.41; 95%CI: 0.53, 2.28) compared to those who decreased their computer use during that period.Conclusion
Specific sedentary behaviors are differentially associated with cognitive performance. In contrast to TV viewing, regular computer use may help maintain cognitive function during the aging process.Clinical Trial Registration
clinicaltrial.gov (number ). NCT00272428相似文献6.
Background
Pervasive negative thoughts about the self are central to the experience of depression. Brain imaging studies in the general population have localised self-related cognitive processing to areas of the medial pre-frontal cortex.Aims
To use fMRI to compare the neural correlates of self-referential processing in depressed and non-depressed participants.Method
Cross-sectional comparison of regional activation using Blood Oxygen Level Dependent (BOLD) fMRI in 13 non-medicated participants with major depressive episode and 14 comparison participants, whilst carrying out a self-referential cognitive task.Results
Both groups showed significant activation of the dorsomedial pre-frontal cortex and posterior cingulate cortex in the ‘self-referent’ condition. The depressed group showed significantly greater activation in the medial superior frontal cortex during the self-referent task. No difference was observed between groups in the ‘other-referent’ condition.Conclusions
Major depressive episode is associated with specific neurofunctional changes related to self-referential processing. 相似文献7.
Background
Studies of perceptual learning have largely focused on unisensory stimuli. However, multisensory interactions are ubiquitous in perception, even at early processing stages, and thus can potentially play a role in learning. Here, we examine the effect of auditory-visual congruency on visual learning.Methodology/Principle Findings
Subjects were trained over five days on a visual motion coherence detection task with either congruent audiovisual, or incongruent audiovisual stimuli. Comparing performance on visual-only trials, we find that training with congruent audiovisual stimuli produces significantly better learning than training with incongruent audiovisual stimuli or with only visual stimuli.Conclusions/Significance
This advantage from stimulus congruency during training suggests that the benefits of multisensory training may result from audiovisual interactions at a perceptual rather than cognitive level. 相似文献8.
Background
Safe Male Circumcision (SMC) is a proven approach for partial protection of men from acquisition of HIV infection. Several sub-Saharan African countries have a target to circumcise 80% of males aged 15 to 49. The use of devices such as PrePex would aid scaling up of SMC. Since most health workers would have no prior experience with use of devices, skills training is needed. This paper explores a skills transfer model at an urban site in Uganda.Objective
To assess the practicability and feasibility of rapid short duration training for safe PrePex device use.Methods
A prospective study, conducted over 8 weeks (August–October 2012) at International Hospital Kampala, an urban Kampala hospital, examining the performance of various health worker cadres after training in the use of a non-surgical device (PrePex). The prospective study obtained approval from the Makerere School of Medicine Research and Ethics Committee and the Uganda National Council of Science and Technology. If eligible, and after the subject signed the informed consent form, they were enrolled into the study.Results
Ten health workers were successfully trained in use of PrePex during a 3 day non-residential on-the-job training course. After the first three days of training, the trained health workers performed 561 placements and 529 device removals successfully. Over all adverse events (AE) rates were below ≤2%; however, there were some differences in AE rates across the cadres trained but not significant (p>0.25 for moderate AEs).Conclusion
Rapid training for safe use of the PrePex device is feasible for the range of health workers available for SMC in resource limited settings, but among those with past SMC experience. 相似文献9.
Pavel Dietz Rolf Ulrich Robert Dalaker Heiko Striegel Andreas G. Franke Klaus Lieb Perikles Simon 《PloS one》2013,8(11)
Purpose
This study assessed, for the first time, prevalence estimates for physical and cognitive doping within a single collective of athletes using the randomized response technique (RRT). Furthermore, associations between the use of legal and freely available substances to improve physical and cognitive performance (enhancement) and illicit or banned substances to improve physical and cognitive performance (doping) were examined.Methods
An anonymous questionnaire using the unrelated question RRT was used to survey 2,997 recreational triathletes in three sports events (Frankfurt, Regensburg, and Wiesbaden) in Germany. Prior to the survey, statistical power analyses were performed to determine sample size. Logistic regression was used to predict physical and cognitive enhancement and the bootstrap method was used to evaluate differences between the estimated prevalences of physical and cognitive doping.Results
2,987 questionnaires were returned (99.7%). 12-month prevalences for physical and cognitive doping were 13.0% and 15.1%, respectively. The prevalence estimate for physical doping was significantly higher in athletes who also used physical enhancers, as well as in athletes who took part in the European Championship in Frankfurt compared to those who did not. The prevalence estimate for cognitive doping was significantly higher in athletes who also used physical and cognitive enhancers. Moreover, the use of physical and cognitive enhancers were significantly associated and also the use of physical and cognitive doping.Discussion
The use of substances to improve physical and cognitive performance was associated on both levels of legality (enhancement vs. doping) suggesting that athletes do not use substances for a specific goal but may have a general propensity to enhance. This finding is important for understanding why people use such substances. Consequently, more effective prevention programs against substance abuse and doping could be developed. 相似文献10.
Konika Banerjee Christopher F. Chabris Valen E. Johnson James J. Lee Fritz Tsao Marc D. Hauser 《PloS one》2009,4(6)
Background
Individual differences in human cognitive abilities show consistently positive correlations across diverse domains, providing the basis for the trait of “general intelligence” (g). At present, little is known about the evolution of g, in part because most comparative studies focus on rodents or on differences across higher-level taxa. What is needed, therefore, are experiments targeting nonhuman primates, focusing on individual differences within a single species, using a broad battery of tasks. To this end, we administered a large battery of tasks, representing a broad range of cognitive domains, to a population of captive cotton-top tamarin monkeys (Saguinus oedipus).Methodology and Results
Using a Bayesian latent variable model, we show that the pattern of correlations among tasks is consistent with the existence of a general factor accounting for a small but significant proportion of the variance in each task (the lower bounds of 95% Bayesian credibility intervals for correlations between g and task performance all exceed 0.12).Conclusion
Individual differences in cognitive abilities within at least one other primate species can be characterized by a general intelligence factor, supporting the hypothesis that important aspects of human cognitive function most likely evolved from ancient neural substrates. 相似文献11.
Study Objectives
To investigate the effect of an eight-week, home-based, personalized, computerized cognitive training program on sleep quality and cognitive performance among older adults with insomnia.Design
Participants (n = 51) were randomly allocated to a cognitive training group (n = 34) or to an active control group (n = 17). The participants in the cognitive training group completed an eight-week, home-based, personalized, computerized cognitive training program, while the participants in the active control group completed an eight-week, home-based program involving computerized tasks that do not engage high-level cognitive functioning. Before and after training, all participants'' sleep was monitored for one week by an actigraph and their cognitive performance was evaluated.Setting
Community setting: residential sleep/performance testing facility.Participants
Fifty-one older adults with insomnia (aged 65–85).Interventions
Eight weeks of computerized cognitive training for older adults with insomnia.Results
Mixed models for repeated measures analysis showed between-group improvements for the cognitive training group on both sleep quality (sleep onset latency and sleep efficiency) and cognitive performance (avoiding distractions, working memory, visual memory, general memory and naming). Hierarchical linear regressions analysis in the cognitive training group indicated that improved visual scanning is associated with earlier advent of sleep, while improved naming is associated with the reduction in wake after sleep onset and with the reduction in number of awakenings. Likewise the results indicate that improved “avoiding distractions” is associated with an increase in the duration of sleep. Moreover, the results indicate that in the active control group cognitive decline observed in working memory is associated with an increase in the time required to fall asleep.Conclusions
New learning is instrumental in promoting initiation and maintenance of sleep in older adults with insomnia. Lasting and personalized cognitive training is particularly indicated to generate the type of learning necessary for combined cognitive and sleep enhancements in this population.Trial Registration
ClinicalTrials.gov NCT00901641http://clinicaltrials.gov/ct2/show/NCT00901641 相似文献12.
Rationale
Huntington disease (HD) is frequently first diagnosed by the appearance of motor symptoms; the diagnosis is subsequently confirmed by the presence of expanded CAG repeats (> 35) in the HUNTINGTIN (HTT) gene. A BACHD rat model for HD carrying the human full length mutated HTT with 97 CAG-CAA repeats has been established recently. Behavioral phenotyping of BACHD rats will help to determine the validity of this model and its potential use in preclinical drug discovery studies.Objectives
The present study seeks to characterize the progressive emergence of motor, sensorimotor and cognitive deficits in BACHD rats.Materials and Methods
Wild type and transgenic rats were tested from 1 till 12 months of age. Motor tests were selected to measure spontaneous locomotor activity (open field) and gait coordination. Sensorimotor gating was assessed in acoustic startle response paradigms and recognition memory was evaluated in an object recognition test.Results
Transgenic rats showed hyperactivity at 1 month and hypoactivity starting at 4 months of age. Motor coordination imbalance in a Rotarod test was present at 2 months and gait abnormalities were seen in a Catwalk test at 12 months. Subtle sensorimotor changes were observed, whereas object recognition was unimpaired in BACHD rats up to 12 months of age.Conclusion
The current BACHD rat model recapitulates certain symptoms from HD patients, especially the marked motor deficits. A subtle neuropsychological phenotype was found and further studies are needed to fully address the sensorimotor phenotype and the potential use of BACHD rats for drug discovery purposes. 相似文献13.
14.
Irena Rektorova Roberta Biundo Radek Marecek Luca Weis Dag Aarsland Angelo Antonini 《PloS one》2014,9(1)
Background
Cortical changes associated with cognitive decline in Parkinson''s disease (PD) are not fully explored and require investigations with established diagnostic classification criteria.Objective
We used MRI source-based morphometry to evaluate specific differences in grey matter volume patterns across 4 groups of subjects: healthy controls (HC), PD with normal cognition (PD-NC), PD with mild cognitive impairment (MCI-PD) and PD with dementia (PDD).Methods
We examined 151 consecutive subjects: 25 HC, 75 PD-NC, 29 MCI-PD, and 22 PDD at an Italian and Czech movement disorder centre. Operational diagnostic criteria were applied to classify MCI-PD and PDD. All structural MRI images were processed together in the Czech centre. The spatial independent component analysis was used to assess group differences of local grey matter volume.Results
We identified two independent patterns of grey matter volume deviations: a) Reductions in the hippocampus and temporal lobes; b) Decreases in fronto-parietal regions and increases in the midbrain/cerebellum. Both patterns differentiated PDD from all other groups and correlated with visuospatial deficits and letter verbal fluency, respectively. Only the second pattern additionally differentiated PD-NC from HC.Conclusion
Grey matter changes in PDD involve areas associated with Alzheimer-like pathology while fronto-parietal abnormalities are possibly an early marker of PD cognitive decline. These findings are consistent with a non-linear cognitive progression in PD. 相似文献15.
Parandoush Abbasian Monika Foroghy Amir Reza Jalilian Amir Hakimi Simindokht Shirvani-Arani 《Reports of Practical Oncology and Radiotherapy》2014,19(3):214-220
Aim
The main purpose of this work was to develop a pharmacokinetic model for the bone pain palliation agent Samarium-153 ethylenediamine tetramethylene phosphonate ([153Sm]-EDTMP) in normal rats to analyze the behavior of the complex.Background
The use of compartmental analysis allows a mathematical separation of tissues and organs to determine the concentration of activity in each fraction of interest. Biodistribution studies are expensive and difficult to carry out in humans, but such data can be obtained easily in rodents.Materials and methods
We have developed a physiologically based pharmacokinetic model for scaling up activity concentration in each organ versus time. The mathematical model uses physiological parameters including organ volumes, blood flow rates, and vascular permabilities; the compartments (organs) are connected anatomically. This allows the use of scale-up techniques to predict new complex distribution in humans in each organ.Results
The concentration of the radiopharmaceutical in various organs was measured at different times. The temporal behavior of biodistribution of 153Sm-EDTMP was modeled and drawn as a function of time.Conclusions
The variation of pharmaceutical concentration in all organs is described with summation of 6–10 exponential terms and it approximates our experimental data with precision better than 2%. 相似文献16.
Ford AH Garrido GJ Beer C Lautenschlager NT Arnolda L Flicker L Almeida OP 《PloS one》2012,7(3):e33345
Background
Elevated total plasma homocysteine (tHcy) has been associated with cognitive impairment, vascular disease and brain atrophy.Methods
We investigated 150 volunteers to determine if the association between high tHcy and cerebral grey matter volume and cognitive function is independent of cardiovascular disease.Results
Participants with high tHcy (≥15 µmol/L) showed a widespread relative loss of grey matter compared with people with normal tHcy, although differences between the groups were minimal once the analyses were adjusted for age, gender, diabetes, hypertension, smoking and prevalent cardiovascular disease. Individuals with high tHcy had worse cognitive scores across a range of domains and less total grey matter volume, although these differences were not significant in the adjusted models.Conclusions
Our results suggest that the association between high tHcy and loss of cerebral grey matter volume and decline in cognitive function is largely explained by increasing age and cardiovascular diseases and indicate that the relationship is not causal. 相似文献17.
Emilie Pasche Patrick Ruch Douglas Teodoro Angela Huttner Stephan Harbarth Julien Gobeill Rolf Wipfli Christian Lovis 《PloS one》2013,8(4)
Background
Improving antibiotic prescribing practices is an important public-health priority given the widespread antimicrobial resistance. Establishing clinical practice guidelines is crucial to this effort, but their development is a complex task and their quality is directly related to the methodology and source of knowledge used.Objective
We present the design and the evaluation of a tool (KART) that aims to facilitate the creation and maintenance of clinical practice guidelines based on information retrieval techniques.Methods
KART consists of three main modules 1) a literature-based medical knowledge extraction module, which is built upon a specialized question-answering engine; 2) a module to normalize clinical recommendations based on automatic text categorizers; and 3) a module to manage clinical knowledge, which formalizes and stores clinical recommendations for further use. The evaluation of the usability and utility of KART followed the methodology of the cognitive walkthrough.Results
KART was designed and implemented as a standalone web application. The quantitative evaluation of the medical knowledge extraction module showed that 53% of the clinical recommendations generated by KART are consistent with existing clinical guidelines. The user-based evaluation confirmed this result by showing that KART was able to find a relevant antibiotic for half of the clinical scenarios tested. The automatic normalization of the recommendation produced mixed results among end-users.Conclusions
We have developed an innovative approach for the process of clinical guidelines development and maintenance in a context where available knowledge is increasing at a rate that cannot be sustained by humans. In contrast to existing knowledge authoring tools, KART not only provides assistance to normalize, formalize and store clinical recommendations, but also aims to facilitate knowledge building. 相似文献18.
Gallagher RM Kirkham JJ Mason JR Bird KA Williamson PR Nunn AJ Turner MA Smyth RL Pirmohamed M 《PloS one》2011,6(12):e28096
Aim
To develop and test a new adverse drug reaction (ADR) causality assessment tool (CAT).Methods
A comparison between seven assessors of a new CAT, formulated by an expert focus group, compared with the Naranjo CAT in 80 cases from a prospective observational study and 37 published ADR case reports (819 causality assessments in total).Main Outcome Measures
Utilisation of causality categories, measure of disagreements, inter-rater reliability (IRR).Results
The Liverpool ADR CAT, using 40 cases from an observational study, showed causality categories of 1 unlikely, 62 possible, 92 probable and 125 definite (1, 62, 92, 125) and ‘moderate’ IRR (kappa 0.48), compared to Naranjo (0, 100, 172, 8) with ‘moderate’ IRR (kappa 0.45). In a further 40 cases, the Liverpool tool (0, 66, 81, 133) showed ‘good’ IRR (kappa 0.6) while Naranjo (1, 90, 185, 4) remained ‘moderate’.Conclusion
The Liverpool tool assigns the full range of causality categories and shows good IRR. Further assessment by different investigators in different settings is needed to fully assess the utility of this tool. 相似文献19.
Riccardo E. Marioni Michael J. Valenzuela Ardo van den Hout Carol Brayne Fiona E. Matthews MRC Cognitive Function Ageing Study 《PloS one》2012,7(12)
Background
Three factors commonly used as measures of cognitive lifestyle are education, occupation, and social engagement. This study determined the relative importance of each variable to long term cognitive health in those with and without severe cognitive impairment.Methods
Data came from 12,470 participants from a multi-centre population-based cohort (Medical Research Council Cognitive Function and Ageing Study). Respondents were aged 65 years and over and were followed-up over 16 years. Cognitive states of no impairment, slight impairment, and moderate/severe impairment were defined, based on scores from the Mini-Mental State Examination. Multi-state modelling was used to investigate links between component cognitive lifestyle variables, cognitive state transitions over time, and death.Results
Higher educational attainment and a more complex mid-life occupation were associated with a lower risk of moving from a non-impaired to a slightly impaired state (hazard ratios 0.5 and 0.8), but with increased mortality from a severely impaired state (1.3 and 1.1). More socially engaged individuals had a decreased risk of moving from a slightly impaired state to a moderately/severely impaired state (0.7). All three cognitive lifestyle variables were linked to an increased chance of cognitive recovery back to the non-impaired state.Conclusions
In those without severe cognitive impairment, different aspects of cognitive lifestyle predict positive cognitive transitions over time, and in those with severe cognitive impairment, a reduced life-expectancy. An active cognitive lifestyle is therefore linked to compression of cognitive morbidity in late life. 相似文献20.
Susanne Rasmussen John H. M. Thornley Anthony J. Parsons Scott J. Harrison 《Annals of botany》2013,111(6):1219-1231