Cognitive control refers to the ability to maintain goal-relevant information in the face of distraction, making it a core construct for understanding human thought and behavior. There is great theoretical and practical value in building theories that can be used to explain or to predict variations in cognitive control as a function of experimental manipulations or individual differences. A critical step toward building such theories is determining which latent constructs are shared between laboratory tasks that are designed to measure cognitive control. In the current work, we examine this question in a novel way by formally linking computational models of two canonical cognitive control tasks, the Eriksen flanker and task-switching task. Specifically, we examine whether model parameters that capture cognitive control processes in one task can be swapped across models to make predictions about individual differences in performance on another task. We apply our modeling and analysis to a large scale data set from an online cognitive training platform, which optimizes our ability to detect individual differences in the data. Our results suggest that the flanker and task-switching tasks probe common control processes. This finding supports the view that higher level cognitive control processes as opposed to solely strategies in speed and accuracy tradeoffs, or perceptual processing and motor response speed are shared across the two tasks. We discuss how our computational modeling substitution approach addresses limitations of prior efforts to relate performance across different cognitive control tasks, and how our findings inform current theories of cognitive control. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Alzheimer's disease (AD) is the most common type of dementia in the US and much of the world with rates increasing exponentially from age 65. Increases in life expectancy in the last century have resulted in a large number of people living to old ages and will result in a quadrupling of AD cases by the middle of the century. Preventing or delaying the onset of AD could have a huge impact in the number of cases expected to develop. The oldest-old are the fastest growing segment of the population and are estimated to account for 12% of the population over 65. Establishing accurate estimates of dementia and AD rates in this group is crucial for public health planning. Prevalence and incidence estimates above age 85 are imprecise and inconsistent because of the lack of very old individuals in most studies. Moreover, risk and protective factors in our oldest citizens have been studied little, and clinical-pathological correlations appear to be poor. We introduce The 90+ Study, established to address some of the unanswered questions about AD and dementia in the oldest-old. Our preliminary results show that close to half of demented oldest-old do not have known cerebral pathology to account for their cognitive deficits. Furthermore, the APOE-e4 allele appears to be a risk factor for AD only in the women in our study. In addition to the challenge of preventing and treating AD, the oldest-old will require major investigative energy to better understand the concomitants of longevity, the causes of dementia, and the factors that promote successful aging in oldest citizens.

Over the past century, we have witnessed a remarkable extension of human life expectancy by >27 years. Reflecting this accomplishment, people >= 90 years of age are now the fastest-growing segment of the population in most of the world. Indeed, more than half of all children born today in developed countries are expected to live to 100 years of age or beyond,(1) and it is remarkable how little we know about these pioneers of aging. Biomedical research tends to focus on disease and poor outcomes, but the oldest-old individuals who have reached extreme age with preserved cognitive health present an unparalleled opportunity to investigate factors that may promote successful cognitive aging throughout the lifespan, even in the presence of neuropathologic changes associated with cognitive loss and dementia.

We investigate the relation between conceptual and syntactic structure by focusing on the phenomenon of circumstantial metonymy e.g., “Table #6 wants another pizza”. We hypothesize that the construal of a metonymic interpretation is facilitated when the metonymized argument e.g., “Table #6” is retrieved before the metonymy-trigger e.g., “wants”, since this gives the processor more time to build the event structure that metonymy demands. This predicts greater cost of metonymy composition when the argument is in object position (after the trigger) relative to subject position (before the trigger). An acceptability task shows a main effect of metonymy for both syntactic positions. A self-paced reading task demonstrates a cost for metonymy only in object position. This indicates that the cost of metonymy composition is rooted in the requirement that the conceptual structure for the metonymic argument be fully retrieved, a process constrained by the order of lexical retrieval provided by syntactic structure.

Helicobacter pylori have coevolved with mankind since its origins, adapting to different human groups. In America, H. pylori has evolved into several subpopulations. We analysed the genome of 154 Colombian strains along with 1,091 strains from worldwide populations to discern the ancestry and adaption to Colombian people. Population structure and ancestry was inferred with FineStructure and ChromoPainter. Phylogenetic relationship and the relative effect of recombination were analysing the core SNPs. Also, a Fst index was calculated to identify the gene variants with the strongest fixation in the Colombian subpopulations compared to their parent population hspSWEurope. FineStructure allowed the identification of two Colombian subpopulations, the previously described hspSWEuropeColombia and a novel subpopulation named hspColombia, that included three subgroups following their geographic origin. Colombian subpopulations represent an admixture of European, African and Indigenous ancestry; although some genomes showed a high proportion of self identity, suggesting an advanced adaption to these mestizo Colombian groups. We found that recombination is more important that punctual mutations in H. pylori genome diversity, 13.9 more important in hspSWEurope, 12.5 in hspSWEColombia and 10.5 in hspColombia, reflecting the divergence of these subpopulations. Fst analysis identified 82 SNPs fixed in 26 genes of the hspColombia subpopulation that encode for outer membrane and central metabolism proteins. Strongest fixation indexes were identified in genes encoding HofC, HopE, FrpB-4 and Sialidase A. These findings demonstrate that H. pylori has evolved in Colombia to give rise to subpopulations with a self identity ancestry, reflected in allele changes on genes encoding for outer membrane proteins.

Background

C-reactive protein (CRP) is a nonspecific marker of inflammation that is increased in the brain and serum of patients with Alzheimer's disease (AD), and has been associated with increased risk of developing dementia. Inflammation increases with age, and the number of people reaching age 90 years and older is growing, making the association between inflammation and dementia increasingly relevant. Using a cross-sectional design, we examined whether high levels of serum CRP are associated with increased odds of prevalent dementia in the oldest-old.

Methods

Serum CRP levels of 305 participants (mean age +/- standard deviation, 94.3 +/- 2.9 years) from the 90+ Study, a longitudinal cohort study of people aged 90 years and older, were evaluated with respect to all-cause dementia. Levels of CRP were divided into three categories: undetectable (<0.5 mg/dL), detectable (0.5-0.7 mg/dL), and elevated (> or =0.8 mg/dL). Odds ratios (ORs) were calculated using logistic regression, and were adjusted for covariates.

Results

Relative to participants with undetectable CRP levels, participants with detectable or elevated CRP levels had increased odds of all-cause dementia (detectable: OR, 3.0; 95% confidence interval, 1.2-7.3; elevated: OR, 5.0; 95% confidence interval, 1.9-12.9). When participants were subdivided by gender, significantly increased ORs were seen only in women.

Conclusions

In the oldest-old, high CRP levels are associated with increased odds of all-cause dementia, particularly in women. Prospective studies are necessary to confirm whether increased CRP levels are associated with an increased risk of developing dementia in this age group.

Purpose of review

People over 90 are the fastest growing segment of the population with the highest rates of dementia. This review highlights recent findings that provide insight to our understanding of dementia and cognition at all ages.

Recent findings

Risk factors for Alzheimer's disease (AD) and dementia differ by age, with some factors, like the development of hypertension, actually becoming protective in the oldest-old. At least half of all dementia in this age group is due to non AD pathologies, including microinfarcts, hippocampal sclerosis and TDP-43. The number of pathologic changes found in the brain is related to both risk and severity of dementia, but many people in this age group appear to be 'resilient' to these pathologies. Resilience to Alzheimer pathology, in part, may be related to absence of other pathologies, and imaging and spinal fluid biomarkers for AD have limited utility in this age group.

Summary

Studies of dementia in the oldest-old are important for our understanding and eventual treatment or prevention of dementia at all ages.