The role of the lateral prefrontal cortex and anterior cingulate in stimulus–response association reversals

Many complex tasks require us to flexibly switch between behavioral rules, associations, and strategies. The prefrontal cerebral cortex is thought to be critical to the performance of such behaviors, although the relative contribution of different components of this structure and associated subcortical regions are not fully understood. We used functional magnetic resonance imaging to measure brain activity during a simple task which required repeated reversals of a rule linking a colored cue and a left/right motor response. Each trial comprised three discrete events separated by variable delay periods. A colored cue instructed which response was to be executed, followed by a go signal which told the subject to execute the response and a feedback instruction which indicated whether to ‘‘hold’’ or ‘‘f lip’’ the rule linking the colored cue and response. The design allowed us to determine which brain regions were recruited by the specific demands of preparing a rule contingent motor response, executing such a response, evaluating the significance of the feedback, and reconfiguring stimulus–response (SR) associations. The results indicate that an increase in neural activity occurs within the anterior cingulate gyrus under conditions in which SR associations are labile. In contrast, lateral frontal regions are activated by unlikely/unexpected perceptual events regardless of their significance for behavior. A network of subcortical structures, including the mediodorsal nucleus of the thalamus and striatum were the only regions showing activity that was exclusively correlated with the neurocognitive demands of reversing SR associations. We conclude that lateral frontal regions act to evaluate the behavioral significance of perceptual events, whereas medial frontal–thalamic circuits are involved in monitoring and reconfiguring SR associations when necessary

Cognitive Impairment and Age-Related Vision Disorders: Their Possible Relationship and the Evaluation of the Use of Aspirin and Statins in a 65 Years-and-Over Sardinian Population

Neurological disorders (Alzheimer’s disease, vascular and mixed dementia) and visual loss (cataract, age-related macular degeneration, glaucoma, and diabetic retinopathy) are among the most common conditions that afflict people of at least 65 years of age. An increasing body of evidence is emerging, which demonstrates that memory and vision impairment are closely, significantly, and positively linked and that statins and aspirin may lessen the risk of developing age-related visual and neurological problems. However, clinical studies have produced contradictory results. Thus, the intent of the present study was to reliably establish whether a relationship exist between various types of dementia and age-related vision disorders, and to establish whether statins and aspirin may or may not have beneficial effects on these two types of disorders. We found that participants with dementia and/or vision problems were more likely to be depressed and displayed worse functional ability in basic and instrumental activities of daily living than controls. Mini mental state examination scores were significantly lower in patients with vision disorders compared to subjects without vision disorders. A closer association with macular degeneration was found in subjects with Alzheimer’s disease than in subjects without dementia or with vascular dementia, mixed dementia, or other types of age-related vision disorders. When we considered the associations between different types of dementia and vision disorders and the use of statins and aspirin, we found a significant positive association between Alzheimer’s disease and statins on their own or in combination with aspirin, indicating that these two drugs do not appear to reduce the risk of Alzheimer’s disease or improve its clinical evolution and may, on the contrary, favor its development. No significant association in statin use alone, aspirin use alone, or the combination of these was found in subjects without vision disorders but with dementia, and, similarly, none in subjects with vision disorders but without dementia. Overall, these results confirm the general impression so far; namely, that macular degeneration may contribute to cognitive disorders (Alzheimer’s disease in particular). In addition, they also suggest that, while statin and aspirin use may undoubtedly have some protective effects, they do not appear to be magic pills against the development of cognitive impairment or vision disorders in the elderly

The intergenerational transmission of cognitive and non-cognitive abilities

We study the intergenerational transmission of cognitive and non-cognitive abilities between parents and sons using population-wide enlistment data. Conscripts are eva-luated at the same age and with comparable methods across cohorts, and we correct for measurement error bias in fathers’ ability measures by using their brothers’ abilities as instruments. The “uncle instrument” is supported by a host of validity tests. This strat-egy also enables us to predict mothers’ abilities. Our results suggest that previous esti-mates of intergenerational ability correlations are biased downwards; in particular for non-cognitive skills. When this bias is corrected for the non-cognitive correlation is close to that of cognitive abilities. Using predicted abilities, we further find the mother-son cognitive ability correlation to be stronger than the father-son correlation. Finally, educational attainment and labor market outcomes of both sons and daughters are found to be strongly related to both parents’ cognitive and non-cognitive abilities.Intergenerational ability correlations; cognitive ability; non-cognitive ability; measurement error bias

Progressive cognitive impairment evolving to dementia parallels parieto-occipital and temporal enlargement in idiopathic chronic hydrocephalus: a retrospective cohort study

Little is known regarding progressive enlargement of the ventricular system in symptomatic patients or asymptomatic subjects. Before eventual surgical treatment, we evaluated the clinical and radiological features of an extremely rare group of patients with idiopathic chronic hydrocephalus (ICH) and cognitive impairment evolving to dementia (n = 11), and an extremely rare group of asymptomatic or minimally symptomatic adults (AMSA) with ventricular enlargement (n = 10). We quantified changes over time in the ventricular frontal, occipital, and temporal horns by measuring the Evans' index plus a parieto-occipital ratio and a temporal ratio, and their percentage of progression. Cerebral ventricles expanded over very long term in both demented patients with ICH and in AMSA. In AMSA, frontal enlargement predominated, whereas demented patients showed predominant parieto-occipital (p = 0.00) and temporal (p = 0.00) enlargement that progressed faster than in AMSA (p = 0.00). In ICH, progression of cognitive impairment parallels ventricular parieto-occipital and temporal horn enlargement. Limitations of this study are the retrospective nature, the non-uniform use of neuropsychological tests, the reduced sample size due to the extremely stringent enrollment criteria, the inability to determine the precise rate of progression

Cognitive Conflict Strategy and Simulation Practicum to Overcome Student Misconception on Light Topics

One way to reduce misconceptions can be overcome by cognitive conflict learning strategies with the help of simulation practicum instead of actual practicum. This study aims to determine whether there are differences in students' misconceptions before and after learning with cognitive conflict strategies as an effort to reduce misconceptions on light material. Research sample of 31 students. Data on the degree of misconception before the study was 0, 36 and after doing research was 0.17. The t-paired test results for the mean percentage of students' misconceptions on light material before and after learning differed at a significance level of 0.05. While, the results of N-Gain calculations to student achievement increase in overcoming misconceptions on light material were 0.3, that means the average students' achievement in dealing with misconceptions are in the medium category and cognitive conflict strategies combined with simulation practicum have a strong effect on reducing students' misconceptions on light material with a range of 2.91. Based on the results of the study it can be concluded that cognitive conflict strategies combined with simulation practicum can be used to reduce misconceptions that lead to increased student learning achievement. Further research is needed to explore students' misconceptions on other physics topics and can measure student misconceptions at each meeting so that students are more organized and developed in learning

Being Knowledgeable of Sociable?: Differences in Relative Importance of Cognitive and Non-Cognitive Skills

This paper develops a model of college admissions that emphasizes their role as a human capital evaluation method. Given multiple dimensions of human capital, di¤erent pattens of human capital evaluation and develpment emerge as equilibria. These equilibria with a varying emphasis on di¤erent aspects of human capital can match an observed di¤erence in college admission patterns between East Asian countries and the U.S. The model has a macroeconomic implication about the relationship between measured human capital and economic performances. We demonstrate the support for this implication through cross-country regressions.

Joint Channel Estimation and Pilot Allocation in Underlay Cognitive MISO Networks

Cognitive radios have been proposed as agile technologies to boost the spectrum utilization. This paper tackles the problem of channel estimation and its impact on downlink transmissions in an underlay cognitive radio scenario. We consider primary and cognitive base stations, each equipped with multiple antennas and serving multiple users. Primary networks often suffer from the cognitive interference, which can be mitigated by deploying beamforming at the cognitive systems to spatially direct the transmissions away from the primary receivers. The accuracy of the estimated channel state information (CSI) plays an important role in designing accurate beamformers that can regulate the amount of interference. However, channel estimate is affected by interference. Therefore, we propose different channel estimation and pilot allocation techniques to deal with the channel estimation at the cognitive systems, and to reduce the impact of contamination at the primary and cognitive systems. In an effort to tackle the contamination problem in primary and cognitive systems, we exploit the information embedded in the covariance matrices to successfully separate the channel estimate from other users' channels in correlated cognitive single input multiple input (SIMO) channels. A minimum mean square error (MMSE) framework is proposed by utilizing the second order statistics to separate the overlapping spatial paths that create the interference. We validate our algorithms by simulation and compare them to the state of the art techniques.Comment: 6 pages, 2 figures, invited paper to IWCMC 201

Cognitive Learning Strategies of Non-english Department Students on Noun Structure

Learning English for non-English department students is not as easy as it seems. Besides, as much as it is necessary to know how successful learners learn, not less important is to know how less successful learners learn. Using think aloud method, this study aims at finding out the cognitive strategies used by the engineering department students in answering incorrectly problems on TOEFL noun structure-the grammar point in which students made the most errors. Findings uncover the students' strategies and reasoning upon which pedagogical implications can be put forth so that more effective and fruitful instruction can be tailored