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While many aspects of cognition have been shown to be shared between humans and non-human animals, there remains controversy regarding whether the capacity to mentally time travel is a uniquely human one. In this paper, we argue that there are four ways of representing when some event happened: four kinds of temporal representation . Distinguishing these four kinds of temporal representation has five benefits. First, it puts us in a position to determine the particular benefits these distinct temporal representations afford an organism. Second, it provides the conceptual resources to foster a discussion about which of these representations is necessary for an organism to count as having the capacity to mentally time travel. Third, it enables us to distinguish stricter from more liberal views of mental time travel that differ regarding which kind(s) of temporal representation is taken to be necessary for mental time travel. Fourth, it allows us to determine the benefits of taking a stricter or more liberal view of mental time travel. Finally, it ensures that disagreement about whether some species can mentally time travel is not merely the product of unrecognized disagreement about which temporal representation is necessary for mental time travel. We argue for a more liberal view, on the grounds that it allows us to view mental time travel as an evolutionarily continuous phenomenon and to recognize that differences in the ways that organisms mentally time travel might reflect different temporal representations, or combinations thereof, that they employ. Our ultimate aim, however, is to create a conceptual framework for further discussion regarding what sorts of temporal representations are required for mental time travel.This article is part of the theme issue 'Elements of episodic memory: lessons from 40 years of research'.

Tulving's introduction of episodic memory and the metaphor of mental time travel has immensely enriched our understanding of human cognition. However, his focus on human psychology, with limited consideration of evolutionary perspectives, led to the entrenched notion that mental time travel is uniquely human. We contend that adopting a phylogenetic perspective offers a deeper insight into cognition, revealing it as a continuous evolutionary process. Adherence to the uniqueness of pre-defined psychological concepts obstructs a more complete understanding. We offer a concise natural history to elucidate how events that occurred hundreds of millions of years ago have been pivotal for our ability to mentally time travel. We discuss how the human brain, utilizing parts with ancient origins in a networked manner, enables mental time travel. This underscores that episodic memories and mental time travel are not isolated mental constructs but integral to our perception and representation of the world. We conclude by examining recent evidence of neuroanatomical correlates found only in great apes, which show great variability, indicating the ongoing evolution of mental time travel in humans.This article is part of the theme issue 'Elements of episodic memory: lessons from 40 years of research'.

The landscape of human memory and event cognition research has witnessed a transformative journey toward the use of naturalistic contexts and tasks. In this review, we track this progression from abrupt, artificial stimuli used in extensively controlled laboratory experiments to more naturalistic tasks and stimuli that present a more faithful representation of the real world. We argue that in order to improve ecological validity, naturalistic study designs must consider the complexity of the cognitive phenomenon being studied. Then, we review the current state of "naturalistic" event segmentation studies and critically assess frequently employed movie stimuli. We evaluate recently developed tools like lifelogging and other extended reality technologies to help address the challenges we identified with existing naturalistic approaches. We conclude by offering some guidelines that can be used to design ecologically valid cognitive neuroscience studies of memory and event cognition., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

On what basis do researchers posit that humans and other animals share cognitive capacities? We argue that such claims are not based on inherent, pre-existing similarities, but rather emerge through a two-step process, which we will call 'anthropofabrication'. In the initial stage, embodied action-based strategies and environmental context in human studies are ignored owing to the need for measurement and quantification. Consequently, cognitive terms become disconnected from the context to which we apply them, and human classificatory cognitive terms are transformed into broad explanatory terms, assumed to be 'species-neutral'. The second phase entails translating and applying these generalized explanatory terms to specific nonverbal animals in ways that serve to further cloak differences between animals and other species. Here, again, researchers selectively discard contextual information to facilitate the comparison with humans. To limit anthropofabrication, we should (re)acknowledge that cognitive abilities are not species-neutral and cannot be detached from embodied action, perception and their context of occurrence. We illustrate our points about anthropofabrication using the example of memory research. This article is part of the theme issue 'Minds in movement: embodied cognition in the age of artificial intelligence'.

Purpose: This study aimed to examine longitudinal associations of workplace effort and reward with changes in cognitive function among United States workers., Methods: Data from the national, population-based Midlife in the United States (MIDUS) study with a 9-year follow-up were used. Validated workplace effort and reward scales were measured at baseline, and cognitive outcomes (including composite cognition, episodic memory, and executive functioning) were measured with the Brief Test of Adult Cognition by Telephone (BTACT) at baseline and follow-up. Multivariable linear regression analyses based on generalized estimating equations (GEE) examined the longitudinal associations under study., Results: Among this worker sample of 1,399, after accounting for demographics, socioeconomics, lifestyle behaviors, health conditions, and job control, high reward at baseline was associated with increased composite cognition (regression coefficient: 0.118 [95% CI: 0.049, 0.187]), episodic memory (0.106 [0.024, 0.188]), and executive functioning (0.123 [0.055, 0.191]) during follow-up. The joint exposure of 'high effort and high reward' was also associated with increased composite cognition (0.130 [0.030, 0.231]), episodic memory (0.131 [0.012, 0.250]), and executive functioning (0.117 [0.017, 0.216]), while the combination of 'low effort and high reward' was associated with increased composite cognition (0.106 [0.009, 0.204]) and executive functioning (0.139 [0.042, 0.235])., Conclusion: Findings suggest that workplace high reward is related to improved cognitive scores among United States workers. Future research should investigate larger cohorts over longer timespans and expand into disease outcomes such as dementia. If these findings emerge as causal, relevant workplace rewards to promote worker cognitive health should be considered., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Cognitive function is a vital component of healthy aging. However, whether a persistently high optimism benefits late-life cognitive function is debatable. The current study examined associations between high optimism status, perceived generativity, and cognitive functions across adulthood. Data were from waves 2 and 3 (2004-14) of the Midlife in the United States study. We used structural equation modeling to examine whether participants' ( N  = 2,205; M age   = 65 ± 11) persistent high optimism predicts better cognitive functions over time, compared to high optimism at only one time-point or not at all while controlling for covariates; we also examined whether individuals' perceived generativity mediates the above association. The findings revealed that persistent high optimism was significantly associated with better episodic memory and executive function. Further, perceived generativity positively mediated the association between persistent high optimism and episodic memory. Future research should examine mechanisms for potential aspects of high optimism and perceived generativity on late-life cognitive performances., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

The first therapeutical goal followed by neurooncological surgeons dealing with prefrontal gliomas is attempting supramarginal tumor resection preserving relevant neurological function. Therefore, advanced knowledge of the frontal aslant tract (FAT) functional neuroanatomy in high-order cognitive domains beyond language and speech processing would help refine neurosurgeries, predicting possible relevant cognitive adverse events and maximizing the surgical efficacy. To this aim we performed the recently developed correlational tractography analyses to evaluate the possible relationship between FAT's microstructural properties and cognitive functions in 27 healthy subjects having ultra-high-field (7-Tesla) diffusion MRI. We independently assessed FAT segments innervating the dorsolateral prefrontal cortices (dlPFC-FAT) and the supplementary motor area (SMA-FAT). FAT microstructural robustness, measured by the tract's quantitative anisotropy (QA), was associated with a better performance in episodic memory, visuospatial orientation, cognitive processing speed and fluid intelligence but not sustained selective attention tests. Overall, the percentual tract volume showing an association between QA-index and improved cognitive scores (pQACV) was higher in the SMA-FAT compared to the dlPFC-FAT segment. This effect was right-lateralized for verbal episodic memory and fluid intelligence and bilateralized for visuospatial orientation and cognitive processing speed. Our results provide novel evidence for a functional specialization of the FAT beyond the known in language and speech processing, particularly its involvement in several higher-order cognitive domains. In light of these findings, further research should be encouraged to focus on neurocognitive deficits and their impact on patient outcomes after FAT damage, especially in the context of glioma surgery., (© 2024. The Author(s).)

Purpose: To investigate the associations between the most popular social media platform WeChat usage and cognitive performance among the middle-aged and older Chinese population using data from a nationally representative survey., Methods: In total, 17,472 participants (≥ 45 years old) from the China Health and Retirement Longitudinal Study (CHARLS, Wave 4, 2018) were analyzed. Cognitive performance including episodic memory and executive function was assessed using Mini-Mental Status Examination (MMSE). Other confounding variables included socio-economic characteristics, medical status, and lifestyle-related information. Multiple linear regression models were used to test the association between cognitive performance and WeChat usage by introducing covariates hierarchically. Subgroup analyses of age and gender were conducted to estimate the robustness of the primary findings., Results: After adjusting for multiple confounders across all linear models, WeChat usage is significantly associated with executive function, episodic memory, and global cognitive performance (all p values<0.05). Such results remained robust in subgroup analyses, stratified by age and gender, and also verified according to longitudinal analyses. Compared to 'Chat-only' users who only used WeChat for online interpersonal communication, further usage of WeChat functions such as using 'Moments' appeared to be significantly associated with better cognitive performance, especially for episodic memory., Conclusion: Social media usage is significantly and positively associated with better cognitive performance among the middle-aged and older Chinese population. Along with point-to-point messaging, using 'Moments' and extended social media platform functions may correlate to better cognitive performance., (© 2024. The Author(s).)

A growing body of research suggests that an episodic specificity induction (ESI), that is, training in recalled details of a (recent) past event, impacts performance on subsequent tasks that require episodic retrieval processes. The constructive episodic simulation hypothesis (Schacter and Addis, 2007) posits that various tasks which require, at least partially, episodic retrieval processes rely on a single, flexible episodic memory system. As such, a specificity induction activates that episodic memory system and improves subsequent performance on tasks that require use of that memory system. The present quantitative review analyzed the literature demonstrating that the Episodic Specificity Induction (ESI) improves performance on subsequence cognitive tasks that require (at least partial) episodic retrieval processes. Twenty-three studies met criteria for measuring the impact of ESI, compared to a non-specificity control induction(s), on subsequent tasks requiring edpisodic retrieval, including memory, imagination, problem solving, divergent thinking. The results of this review demonstrate a strong, positive effect of ESI on episodic memory, imagination, divergent thinking, and problem-solving tasks., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The angular gyrus (AG) and posterior cingulate cortex (PCC) demonstrate extensive structural and functional connectivity with the hippocampus and other core recollection network regions. Consequently, recent studies have explored neuromodulation targeting these and other regions as a potential strategy for restoring function in memory disorders such as Alzheimer's Disease. However, determining the optimal approach for neuromodulatory devices requires understanding how parameters like selected stimulation site, cognitive state during modulation, and stimulation duration influence the effects of deep brain stimulation (DBS) on electrophysiological features relevant to episodic memory. We report experimental data examining the effects of high-frequency stimulation delivered to the AG or PCC on hippocampal theta oscillations during the memory encoding (study) or retrieval (test) phases of an episodic memory task. Results showed selective enhancement of anterior hippocampal slow theta oscillations with stimulation of the AG preferentially during memory retrieval. Conversely, stimulation of the PCC attenuated slow theta oscillations. We did not observe significant behavioral effects in this (open-loop) stimulation experiment, suggesting that neuromodulation strategies targeting episodic memory performance may require more temporally precise stimulation approaches., Competing Interests: Declaration of competing interest None., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Introduction: Educational differences in cognitive performance among older adults are well documented. Studies that explore this association typically estimate a single average effect of education on cognitive performance. We argue that the processes that contribute to the association between education and cognitive performance are unlikely to have equal effects at all levels of cognitive performance. In this study, we employ an analytical approach that enables us to go beyond averages to examine the association between education and five measures of global and domain-specific cognitive performance across the outcome distributions., Methods: This cross-sectional study included 1,780 older adults aged 58-68 years from the Longitudinal Aging Study Amsterdam. Conditional quantile regression was used to examine variation across the outcome distribution. Cognitive outcomes included Mini-Mental State Examination (MMSE) score, crystallized intelligence, information processing speed, episodic memory, and a composite score of global cognitive performance., Results: The results showed that the associations between education and different cognitive measures varied across the outcome distributions. Specifically, we found that education had a stronger association with crystallized intelligence, MMSE, and a composite cognitive performance measure in the lower tail of performance distributions. The associations between education and information processing speed and episodic memory were uniform across the outcome distributions., Conclusion: Larger associations between education and some domains of cognitive performance in the lower tail of the performance distributions imply that inequalities are primarily generated among individuals with lower performance rather than among average and high performers. Additionally, the varying associations across some of the outcome distributions indicate that estimating a single average effect through standard regression methods may overlook variations in cognitive performance between educational groups. Future studies should consider heterogeneity across the outcome distribution., (© 2023 The Author(s). Published by S. Karger AG, Basel.)

Objectives: The goal of this preregistered study was to synthesize empirical findings on age differences in motivated cognition using a meta-analytic approach, with a focus on the domains of cognitive control and episodic memory., Methods: A systematic search of articles published before July 2022 yielded 27 studies of cognitive control (N = 1,908) and 73 studies of memory (N = 5,837). Studies had to include healthy younger and older adults, a within-subjects or between-subjects comparison of motivation (high vs low), and a measure of cognitive control or memory. The Age × Motivation effect size was meta-analyzed using random-effects models, and moderators were examined using meta-regressions and subgroup analyses., Results: Overall, the Age × Motivation interaction was not significant in either cognitive domain, but the effect sizes in both domains were significantly heterogeneous, indicating a possible role of moderating factors in accounting for effect size differences. Moderator analyses revealed significant moderation by incentive type for episodic memory, but not for cognitive control. Older adults' memory was more sensitive to socioemotional rewards, whereas younger adults' memory was more sensitive to financial gains., Discussion: Findings are discussed with reference to the dopamine hypothesis of cognitive aging and to life-span theories of motivational orientation. None of these theories is fully supported by the meta-analysis findings, highlighting the need for an integration of neurobiological, cognitive process, and life-span-motivational perspectives., (© The Author(s) 2023. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Limited research is available on the relationship between social stress and risk of declining cognition. We sought to examine whether social stress has adverse effects on risk of declining episodic memory and executive functioning in aging individuals. We used data from the MIDUS study, a national probability sample of non-institutionalized, English speaking respondents aged 25-74 living in the 48 contiguous states of the United States. The initial wave (1995) included 4963 non-institutionalized adults aged 32-84 (M = 55, SD = 12.4). We used an analytic sample from MIDUS-II (1996/1997) and MIDUS-III (2013) (n = 1821). The dependent variables are episodic memory and executive functioning, which were assessed with the Brief Test for Cognition (BTACT). The independent variables were social stress variables (subjective social status, family and marital stress, work stress and discrimination). To evaluate episodic memory and executive functioning changes over a time period of 10 years, we estimated adjusted linear regression models. Women report significantly lower subjective social status and more discrimination stress than men across all age groups. Controlling for education and income, age, and baseline episodic memory and executive functioning, lower subjective social status had additional adverse effects on declines in episodic memory in men and women. Marital risk had adverse effects on episodic memory in men but not in women. Daily discrimination had adverse effects on executive functioning on all individuals. Public health strategies should focus on reducing social stress in a socio-ecological perspective. Especially, subjective social status and discrimination stress might be a target for prevention efforts., (© 2021. The Author(s).)

Objectives: Active lifestyles are related to higher levels of cognitive functioning. Fewer studies have examined the importance of engaging in different activities (activity variety) for cognitive functioning. Moreover, it is unclear whether activity variety in specific domains (i.e., cognitive, physical, or social) is important for cognitive health. The current study examined whether overall activity variety as well as variety in specific domains relate to cognitive functioning., Methods: In Waves 2 and 3 of the Survey of Midlife Development in the United States, 3,337 adults reported their activity engagement and completed a cognitive battery. For longitudinal analyses, 2,049 participants were classified into 4 groups based on their rank ordering of activity variety across 9 years (remained high, increased, decreased, or remained low)., Results: Cross-sectional analyses revealed that overall activity variety was related to higher cognitive functioning over and above activity frequency; physical and social activity variety each contributed significantly and uniquely to this association. Longitudinal analyses revealed that those with consistently low overall activity variety at both waves had lower cognitive functioning at Wave 3 than those with high activity variety at either wave, after adjusting for cognitive functioning at Wave 2. Those with consistently high or increasing social activity variety had higher cognitive functioning at Wave 3 than participants with low activity variety at both waves., Discussion: Findings suggest that activity variety, particularly in the social domain, is related to concurrent and future cognitive function across adulthood., (© The Author(s) 2022. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Purpose: The global population is ageing. Evidence show dietary patterns may be associated with cognitive status in older adults. This cross-sectional study investigated associations between dietary patterns and cognitive function in older adults in New Zealand., Methods: The REACH study (Researching Eating, Activity, and Cognitive Health) included 371 participants (65-74 years, 36% male) living independently in Auckland, New Zealand. Valid and reproducible dietary patterns were derived, using principal component analysis, from dietary data collected by a 109-item validated food frequency questionnaire. Six cognitive domains (global cognition, attention and vigilance, executive function, episodic memory, working memory, and spatial memory) were tested using COMPASS (Computerised Mental Performance Assessment System). Associations between dietary patterns and cognitive scores, adjusted for age, sex, education, physical activity, energy, and Apolipoprotein E-ε4 status were analysed using multiple linear regression analysis., Results: Three dietary patterns explained 18% of dietary intake variation-'Mediterranean style' (comprising: salad vegetables, leafy cruciferous vegetables, other vegetables, avocados and olives, alliums, nuts and seeds, white fish and shellfish, oily fish, and berries); 'Western' (comprising: processed meats, sauces and condiments, cakes, biscuits and puddings, meat pies and chips, and processed fish); and 'Prudent' (comprising: dried legumes, soy-based foods, fresh and frozen legumes, whole grains, and carrots). No associations between any cognitive domain and dietary pattern scores were observed. Global cognitive function was associated with being younger and having a university education., Conclusion: In this cohort of community-dwelling, older adults in New Zealand, current dietary patterns were not associated with cognitive function., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany.)

Objective: During the past decade, the pediatric suicide rate has nearly tripled. Yet, little is known about suicide behavior (SB) in children. Identification of risk factors associated with SB during childhood may be critical to preventing future attempts. The purpose of this study was to examine the relationship between neurocognitive performance and suicide ideation (SI) in children., Method: The present study utilized baseline data from 11,875 participants in the Adolescent Brain Cognitive Development (ABCD) study, a longitudinal study that follows 9- and 10-year-old children through late adolescence to examine factors that influence developmental trajectories. Suicidality was assessed by the Kiddie Schedule for Affective Disorder and Schizophrenia (KSADS) suicide module completed by the parent. Neurocognitive ability was assessed using the NIH Toolbox Cognition measures administered to the youth., Results: Children with a history of SI reported by their parent or concordant parent and youth report of SI demonstrated lower performance on the NIH Toolbox Picture Sequence Memory Test compared to children without SI. The difference in performance on the memory task remained significant when including demographic characteristics, family history of suicide, and internalizing symptoms in the model as covariates., Conclusions: To our knowledge, this is the first study to identify decreased episodic memory in children with SI. These findings are similar to results from adult and adolescent studies which have reported decreased memory performance among suicide attempters. Deficits in episodic memory may impact a child's ability to problem-solve and generate potential future outcomes, which may increase the risk for SB. Early identification of memory deficits in children may inform suicide prevention and intervention efforts.Highlights6% of parents and children reported a history of active suicide ideation in children.Children with a history of suicide ideation had lower episodic memory performance.Early identification of memory deficits may inform suicide intervention efforts.

Objectives: Age-related differences in cognition are typically assessed by comparing groups of older to younger participants, but little is known about the continuous trajectory of cognitive changes across age, or when a shift to older adulthood occurs. We examined the pattern of mean age differences and variability on episodic memory and executive function measures over the adult life span, in a more fine-grained way than past group or life-span comparisons., Method: We used a sample of over 40,000 people aged 18-90 who completed psychometrically validated online tests measuring episodic memory and executive functions (the Cogniciti Brain Health Assessment)., Results: Cognitive performance declined gradually over adulthood, and rapidly later in life on spatial working memory, processing speed, facilitation (but not interference), associative recognition, and set shifting. Both polynomial and segmented regression fit the data well, indicating a nonlinear pattern. Segmented regression revealed a shift from gradual to rapid decline that occurred in the early 60s. Variability between people (interindividual variability or diversity) and variability within a person across tasks (intraindividual variability or dispersion) also increased gradually until the 60s, and rapidly after. Confirmatory factor analysis revealed a single general factor (of variance shared between tasks) offered a good fit for performance across tasks., Discussion: Life-span cognitive performance shows a nonlinear pattern, with gradual decline over early and mid-adulthood, followed by a transition in the 60s to notably accelerated, but more variable, decline. Some people show less decline than others, and some cognitive abilities show less within-person decline than others., (© The Author(s) 2021. Published by Oxford University Press on behalf of The Gerontological Society of America.)

This literature review provides the first comprehensive qualitative and quantitative systematic synthesis of acute laboratory stress effects on older adults' cognition by specifying the direction and magnitude of those effects both overall and for different cognitive processes separately. A systematic literature search was performed, and effect sizes estimated whenever possible. We found meta-analytical evidence that stress has negative effects on older adults' verbal fluency (g adj = -0.53, 95 % CI [-2.70, 1.63]), null-to-negative effects on episodic memory (g adj = -0.26, 95 % CI [-0.44, -0.08]), null effects on executive functions (g adj = 0.07, 95 % CI [-0.31, 0.46]), and enhancing effects on working memory (g adj = 0.16, 95 % CI [-0.01, 0.33]). Relating these findings to those in young adults, notable differences emerged for some cognitive functions, such as opposing effects on working memory between age groups. Our review further reveals that stress effects on older adults' memory retention, associative memory, prospective memory, interference control or cognitive flexibility are heavily understudied. We provide a conceptual and methodological framework for future studies in older adults., (Copyright © 2021 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Memory has an essential function in human life as it helps individuals remember and recognize their surroundings. It is also the major form of cognition that controls behavior. As memory is a function that is highly characteristic of humans, how it was established is of particular interest. Recent progress in the field of neurosciences, together with the technological advancement of genome-wide approaches, has led to the accumulation of evidence regarding the presence and similar/distinct mechanisms of memory among species. However, the understanding of the evolution of memory obtained utilizing these genome-wide approaches remains unclear. The purpose of this review was to provide an overview of the literature on the evolution of the memory system among species and the genes involved in this process. This review also discusses possible approaches to study the evolution of memory systems to guide future research., (© 2021 The Authors. FEBS Open Bio published by John Wiley & Sons Ltd on behalf of Federation of European Biochemical Societies.)

Feedback is an important factor to enhance subsequent memory, showing that memory performance increases after the feedback than after the no feedback condition during retrieval practice. However, most studies have provided answers as feedback and only examined memory accuracy. It is unclear whether memory is enhanced over time when other types of feedback (e.g., correct/incorrect) is given. In addition, during retrieval practice, participants' responses differ in correctness and confidence level. To what extent these initial memory features interact with feedback type to influence subsequent memory accuracy and confidence level remains unclear. In this study, to address these questions, participants learned a series of sentences, then during the retrieval practice phase, different types of feedback-feedback with correct/incorrect and answer (CA-feedback), feedback with answer (A-feedback), feedback with correct/incorrect (C-feedback), and no feedback-were given after they performed a cued-recall test and rated the confidence. After retention intervals of 5 min, 1 day, and 7 days, they took final tests, followed by the confidence rating. The results showed that different types of feedback influenced subsequent memory and forgetting by different mechanisms. The CA-feedback and A-feedback enhanced memory performance by correcting initial errors and increasing the confidence of correct trials, but the corrected memory was more easily forgotten from 5 min to 7 days. Compared to A-feedback, the CA-feedback maintained the corrected memory after 1 day. The C-feedback did not correct initial errors but slowed the forgetting rate and reduced the confidence of incorrect trials. This study highlighted the interaction between feedback type and initial memory features (correctness, confidence) to influence subsequent memory performance, including memory accuracy and confidence level., (© 2021 The Authors. PsyCh Journal published by Institute of Psychology, Chinese Academy of Sciences and John Wiley & Sons Australia, Ltd.)

People regularly outsource parts of their memory onto external memory stores like computers or smartphones. Such cognitive offloading can enhance subsequent memory performance, as referred to the saving-enhanced memory effect (Storm & Stone, 2015). The cognitive mechanisms of this effect are not clear to date, however similarities to list-method directed forgetting (LMDF) have been stated. Here, we examined in 52 participants the electrophysiological (EEG) correlates of the saving-enhanced memory effect and compared our results to earlier LMDF findings (Hanslmayr et al., 2012). For this purpose, EEG alpha power and alpha phase synchrony during the encoding of two word lists were compared as a function of saving or no-saving. We hypothesised that if saving-enhanced memory was related to LMDF, saving in comparison to no-saving between lists should reduce alpha power and alpha phase synchrony during List 2 encoding, two effects that have been related to List 2 encoding benefits and List 1 inhibition in the earlier LMDF work. The results showed no statistically significant saving-enhanced memory effect and no significant effects in EEG alpha power or alpha phase synchrony. Possible explanations for and implications of these non-significant findings are discussed., (© 2021 The Authors. European Journal of Neuroscience published by Federation of European Neuroscience Societies and John Wiley & Sons Ltd.)

Late-onset Alzheimer's disease (AD) disproportionately affects women compared to men. Episodic memory decline is one of the earliest and most pronounced deficits observed in AD. However, it remains unclear whether sex influences episodic memory-related brain function in cognitively intact older adults at risk of developing AD. Here we used task-based multivariate partial least squares analysis to examine sex differences in episodic memory-related brain activity and brain activity-behavior correlations in a matched sample of cognitively intact older women and men with a family history of AD from the PREVENT-AD cohort study in Montreal, Canada (M age =63.03±3.78; M education =15.41±3.40). We observed sex differences in task-related brain activity and brain activity-behavior correlations during the encoding of object-location associative memories and object-only item memory, and the retrieval of object only item memories. Our findings suggest a generalization of episodic memory-related brain activation and performance in women compared to men. Follow up analyses should test for sex differences in the relationship between brain activity patterns and performance longitudinally, in association with risk factors for AD development. This article is part of the Virtual Special Issue titled COGNITIVE NEUROSCIENCE OF HEALTHY AND PATHOLOGICAL AGING. The full issue can be found on ScienceDirect at https://www.sciencedirect.com/journal/neurobiology-of-aging/special-issue/105379XPWJP., (Crown Copyright © 2021. Published by Elsevier Inc. All rights reserved.)

Although rodent research provides important insights into neural correlates of human psychology, new cortical areas, connections, and cognitive abilities emerged during primate evolution, including human evolution. Comparison of human brains with those of nonhuman primates reveals two aspects of human brain evolution particularly relevant to emotional disorders: expansion of homotypical association areas and expansion of the hippocampus. Two uniquely human cognitive capacities link these phylogenetic developments with emotion: a subjective sense of participating in and reexperiencing remembered events and a limitless capacity to imagine details of future events. These abilities provided evolving humans with selective advantages, but they also created proclivities for emotional problems. The first capacity evokes the "reliving" of past events in the "here-and-now," accompanied by emotional responses that occurred during memory encoding. It contributes to risk for stress-related syndromes, such as posttraumatic stress disorder. The second capacity, an ability to imagine future events without temporal limitations, facilitates flexible, goal-related behavior by drawing on and creating a uniquely rich array of mental representations. It promotes goal achievement and reduces errors, but the mental construction of future events also contributes to developmental aspects of anxiety and mood disorders. With maturation of homotypical association areas, the concrete concerns of childhood expand to encompass the abstract apprehensions of adolescence and adulthood. These cognitive capacities and their dysfunction are amenable to a research agenda that melds experimental therapeutic interventions, cognitive neuropsychology, and developmental psychology in both humans and nonhuman primates.

Objectives: Participating in a variety of daily activities (i.e., activity diversity) requires people to adjust to a variety of situations and engage in a greater diversity of behaviors. These experiences may, in turn, enhance cognitive functioning. This study examined associations between activity diversity and cognitive functioning across adulthood., Method: Activity diversity was defined as the breadth and evenness of participation in seven common daily activity domains (e.g., paid work, time with children, leisure, physical activities, volunteering). Participants from the National Survey of Daily Experiences (NSDE: N = 732, Mage = 56) provided activity data during eight consecutive days at Wave 1 (W1) and Wave 2 (W2) 10 years apart. They also provided cognitive data at W2., Results: Greater activity diversity at W2 was associated with higher overall cognitive functioning and higher executive functioning at W2. Individuals who increased activity diversity from W1 to W2 also exhibited higher scores in overall cognitive functioning and executive functioning at W2. Overall cognitive functioning, executive functioning, and episodic memory were better in those who had higher activity diversity at both waves, or increased activity diversity from W1 to W2, compared to those who had lower activity diversity or decreased activity diversity over time., Discussion: Activity diversity is important for cognitive health in adulthood. Future work can study the directionality between activity diversity and cognitive functioning and underlying social and neurological mechanisms for these associations., (© The Author(s) 2020. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: Epidemiological studies show an association between masticatory function and cognitive impairment. This has further strengthened the notion that tooth loss and impaired masticatory function may be risk factors for dementia and cognitive decline. Animal experiments have indicated a causal relationship and several possible mechanisms have been discussed. This evidence is, however, lacking in humans. Therefore, in the current interventional study, we aim to investigate the effect of rehabilitation of masticatory function on cognition in older adults., Methods: Eighty patients indicated for prosthodontic rehabilitation will be randomly assigned to an experimental or a control group. Participants will conduct neuropsychological assessments, masticatory performance tests, saliva tests, optional magnetic resonance imaging, and answer questionnaires on oral health impact profiles and hospital anxiety and depression scale before, 3 months, and 1 year after oral rehabilitation. The difference between the two groups is that the control group will be tested an additional time, (at an interval of about 3 months) before the onset of the oral rehabilitation procedure. The primary outcome is a change in measures of episodic memory performance., Discussion: Although tooth loss and masticatory function are widespread in older people, it is still an underexplored modifiable risk factor potentially contributing to the development of cognitive impairment. If rehabilitation of masticatory function shows positive effects on the neurocognitive function, this will have great implications on future health care for patients with impaired masticatory status. The present project may provide a new avenue for the prevention of cognitive decline in older individuals., Trial Registration: The protocol for the study was retrospectively registered in ClinicalTrials.gov Identifier: NCT04458207, dated 02-07-2020.

Background: Dementia is among the most common chronic noncommunicable neurodegenerative diseases. In the long term, it causes disability and loss of autonomy and independence. It is estimated that there are 35.6 million people with Alzheimer's disease worldwide. Several clinical aspects of this disease have been widely studied, but the main focus of study has been memory loss, which is one of the first symptoms. The present study proposes an innovative intervention that combines cognitive training and multisite transcranial direct current stimulation, which interferes with other clinical aspects of the subject., Case Presentation: In this study, we present two subjects diagnosed with mild Alzheimer's disease. Subject 1 is an 82-year-old Brazilian Latin American woman with a high school education who was diagnosed with Alzheimer's disease 8 years ago and uses an Exelon patch. Subject 2 is an 88-year-old Brazilian Latin American woman with an incomplete primary education who was diagnosed with Alzheimer's disease 1 year ago and received medical orientation to temporarily discontinue medications for Alzheimer's disease. Both participants were subjected to intermittent cognitive training sessions and concomitant transcranial stimulation in three weekly 30-minute sessions in which a brain area was stimulated every 10 minutes for a total of 24 sessions, with a 2-month follow-up. Transcranial stimulation was applied to six different regions of the cortex: the dorsolateral prefrontal cortex bilaterally, the somatosensory association cortex bilaterally and Broca's and Wernicke's areas. Comparing the results of tests performed before and after the treatment period, a 1-point improvement was observed for both subjects on the Word Recall task of the Alzheimer Disease Assessment Scale, which evaluates symptoms related to the decline of episodic memory. Improvement in the executive functions domain was also observed through the results of the Stroop test, Victoria version., Conclusions: The results from the two presented cases show that multisite transcranial stimulation associated with cognitive training is an effective adjuvant method for the treatment of patients diagnosed with mild Alzheimer's disease. Its effects can benefit patients' daily routines by reducing cognitive deficits by keeping intact areas active and/or compensating for lost functions. Trial registration NCT02772185. Registered 13 May 2016, http://www.clinicaltrials.gov/ct2/show/NCT02772185 . Retrospectively registered.

Background: We aimed to examine the effect of physical activity on different cognitive domains among patients with diabetes., Methods: We used two waves of data from the Chinese Health and Retirement Longitudinal Study (CHARLS, 2013-2015), a nationally representative dataset of Chinese population aged over 45. Total physical activity scores were calculated based on the International Physical Activity Questionnaire (IPAQ). Executive function and episodic memory were used as measures of cognitive function. We conducted lagged dependent variable models to explore the association between physical activity and cognitive function in full sample as well as two different age groups (45-65, ≥65)., Results: 862 diabetic patients were included. We found that diabetic participants who had greater level of physical activity at baseline were associated with better episodic memory function in 2 years (p < 0.05). Moreover, physical activity was significantly associated with less decline in episodic memory in fully adjusted models, and the associations were stronger among patients aged 45-65 years (p < 0.05). No statistically significant association was found between physical activity and executive function in all age groups., Conclusions: Physical activity may prevent some of the potential decline in episodic memory in diabetic patients. Clinicians and public health departments should strengthen the promotion of physical activity and develop early screening tools among diabetic participants to prevent the progression of cognitive impairment.

Introduction: Counteracting impaired brain glucose metabolism with ketones may improve cognition in mild cognitive impairment (MCI)., Methods: Cognition, plasma ketone response, and metabolic profile were assessed before and 6 months after supplementation with a ketogenic drink containing medium chain triglyceride (ketogenic medium chain triglyceride [kMCT]; 15 g twice/day; n = 39) or placebo (n = 44)., Results: Free and cued recall (Trial 1; P = .047), verbal fluency (categories; P = .024), Boston Naming Test (total correct answers; P = .033), and the Trail-Making Test (total errors; P = .017) improved significantly in the kMCT group compared to placebo (analysis of covariance; pre-intervention score, sex, age, education, and apolipoprotein E4 as covariates). Some cognitive outcomes also correlated positively with plasma ketones. Plasma metabolic profile and ketone response were unchanged., Conclusions: This kMCT drink improved cognitive outcomes in MCI, at least in part by increasing blood ketone level. These data support further assessment of MCI progression to Alzheimer's disease., (© 2020 The Authors. Alzheimer's & Dementia published by Wiley Periodicals LLC on behalf of Alzheimer's Association.)

Typical methods to study cognitive function are to record the electrical activities of animal neurons during the training of animals performing behavioral tasks. A key problem is that they fail to record all the relevant neurons in the animal brain. To alleviate this problem, we develop an RNN-based Actor-Critic framework, which is trained through reinforcement learning (RL) to solve two tasks analogous to the monkeys' decision-making tasks. The trained model is capable of reproducing some features of neural activities recorded from animal brain, or some behavior properties exhibited in animal experiments, suggesting that it can serve as a computational platform to explore other cognitive functions. Furthermore, we conduct behavioral experiments on our framework, trying to explore an open question in neuroscience: which episodic memory in the hippocampus should be selected to ultimately govern future decisions. We find that the retrieval of salient events sampled from episodic memories can effectively shorten deliberation time than common events in the decision-making process. The results indicate that salient events stored in the hippocampus could be prioritized to propagate reward information, and thus allow decision-makers to learn a strategy faster., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

In working memory (WM), successful maintenance of information is affected by interference. Older adults may be especially susceptible to the effects of interference, which may cause age-related cognitive impairments. A relative score of IC was derived from cross-sectional (n = 869) and longitudinal (n = 443) data to investigate (1) if IC is reduced in normal aging, (2) if individual differences in IC related to individual performance in other cognitive domains, and (3) if 5-year change in IC is related to change in general cognition. Older age was associated with reduced IC, but no decline in IC occurred over 5 years. Also, the ability to control interference in WM was related to performance in episodic memory, verbal fluency, and block design. We also found that IC mediates the relationship between age and cognition, suggesting that age-related cognitive decline is linked to IC. Finally, we demonstrate that change in IC was related to decline in episodic memory.

Time-based prospective memory (TBPM) allows us to remember to perform intended actions at a specific time in the future. TBPM is sensitive to the effects of age, but the neural substrates of this decline are still poorly understood. The aim of the present study was thus to better characterize the brain substrates of the age-related decline in TBPM, focusing on macrostructural gray matter and microstructural white matter integrity. We administered a TBPM task to 22 healthy young (26 ± 5.2 years) and 23 older (63 ± 5.9 years) participants, who also underwent volumetric magnetic resonance imaging and diffusion tensor imaging scans. Neuroimaging analyses revealed lower gray matter volumes in several brain areas in older participants, but these did not correlate with TBPM performance. By contrast, an age-related decline in fractional anisotropy in several white-matter tracts connecting frontal and occipital regions did correlate with TBPM performance, whereas there was no significant correlation in healthy young subjects. According to the literature, these tracts are connected to the anterior prefrontal cortex and the thalamus, 2 structures involved in TBPM. These results confirm the view that a disconnection process occurs in aging and contributes to cognitive decline., (© The Author(s) 2020. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: Sex differences in cognitive functioning in old age are known to exist yet are still poorly understood., Objective: This study examines to what extent differences in cardiovascular risk factors and cardiovascular disease between men and women explain sex differences in cognitive functioning., Methods: Data from 2,724 older adults from the Longitudinal Aging Study Amsterdam were used. Information processing speed and episodic memory, measured three times during six years of follow-up, served as outcomes. The mediating role of cardiovascular risk factors and cardiovascular disease was examined in single and multiple mediator models. Determinant-mediator effects were estimated using linear or logistic regression, and determinant-outcome and mediator-outcome effects were estimated using linear mixed models. Indirect effects were estimated using the product-of-coefficients estimator., Results: Women scored 1.58 points higher on information processing speed and 1.53 points higher on episodic memory. Several cardiovascular risk factors had small mediating effects. The sex difference in information processing speed was mediated by smoking, depressive symptoms, obesity, and systolic blood pressure. The sex difference in episodic memory was mediated by smoking, physical activity, and depressive symptoms. Effects of smoking, LDL cholesterol, and diabetes mellitus on information processing speed differed between men and women., Conclusion: Differences in cardiovascular risk factors between women and men partially explained why women had better cognitive functioning. A healthy cardiovascular lifestyle seems beneficial for cognition and sex-specific strategies may be important to preserve cognitive functioning at older age.

Background: Cognitive complaints are gaining more attention as they may represent an early marker of increased risk for AD in individuals without objective decline at standard neuropsychological examination., Objective: Our aim was to assess whether cognitive complaints in late middle-aged individuals not seeking medical help are related to objective cognitive outcomes known as early markers for AD risk, concomitant affective state, and amyloid-β (Aβ) burden., Methods: Eighty-seven community-based cognitively normal individuals aged 50-69 years underwent neuropsychological assessment for global cognition, using Preclinical Alzheimer's Cognitive Composite 5 (PACC5) score, and a more specific episodic memory measure. Affective state was based on self-assessment questionnaires for depression and anxiety. Aβ PET burden was assessed via [18F]Flutemetamol (N = 84) and [18F]Florbetapir (N = 3) uptake. Cognitive complaints were evaluated using Cognitive Difficulties Scale., Results: Higher cognitive complaints were significantly associated with lower episodic memory performance and worse affective state. Moreover, higher level of cognitive complaints was related to higher (but still sub-clinical) global Aβ accumulation (at uncorrected significance level). Importantly, all three aspects remained significant when taken together in the same statistical model, indicating that they explained distinct parts of variance., Conclusion: In healthy Aβ negative late middle-aged individuals, a higher degree of cognitive complaints is associated with lower episodic memory efficiency, more anxiety and depression, as well as, potentially, with higher Aβ burden, suggesting that complaints might signal subtle decline. Future studies should untangle how cognitive complaints in healthy aging populations are related to longitudinal changes in objective cognition and AD biomarker correlates.

Heterogeneity in episodic memory functioning in aging was assessed with a pattern-completion functional magnetic resonance imaging task that required reactivation of well-consolidated face-name memory traces from fragmented (partial) or morphed (noisy) face cues. About half of the examined individuals (N = 101) showed impaired (chance) performance on fragmented faces despite intact performance on complete and morphed faces, and they did not show a pattern-completion response in hippocampus or the examined subfields (CA1, CA23, DGCA4). This apparent pattern-completion deficit could not be explained by differential hippocampal atrophy. Instead, the impaired group displayed lower cortical volumes, accelerated reduction in mini-mental state examination scores, and lower general cognitive function as defined by longitudinal measures of visuospatial functioning and speed-of-processing. In the full sample, inter-individual differences in visuospatial functioning predicted performance on fragmented faces and hippocampal CA23 subfield activity over 25 years. These findings suggest that visuospatial functioning in middle age can forecast pattern-completion deficits in aging., (Copyright © 2020 The Author(s). Published by Elsevier Inc. All rights reserved.)

Cognition is a crucial element of human functionality. Like any other physical capability, cognition is both enabled and limited by tissue biology. The aim of this study was to investigate whether oxygen is a rate-limiting factor for any of the main cognitive domains in healthy young individuals. Fifty-six subjects were randomly assigned to either increased oxygen supply using hyperbaric oxygen (two atmospheres of 100% oxygen) or to a "sham" treatment (a simulation of increased pressure in a chamber with normal air). While in the chamber, participants went through a battery of tests evaluating the major cognitive domains including information processing speed, episodic memory, working memory, cognitive flexibility, and attention. The results demonstrated that from all evaluated cognitive domains, a statistically significant improvement was found in the episodic memory of the hyper-oxygenized group. The hyper-oxygenized group demonstrated a better learning curve and a higher resilience to interference. To conclude, oxygen delivery is a rate-limiting factor for memory function even in healthy young individuals under normal conditions. Understanding the biological limitations of our cognitive functions is important for future development of interventional tools that can be used in daily clinical practice.

A cognitive map, representing an environment around oneself, is necessary for spatial navigation. However, compared with its constituent elements such as individual landmarks, neural substrates of coherent spatial information, which consists in a relationship among the individual elements, remain largely unknown. The present study investigated how the brain codes map-like representations in a virtual environment specified by the relative positions of three objects. Representational similarity analysis revealed an object-based spatial representation in the hippocampus (HPC) when participants located themselves within the environment, while the medial prefrontal cortex (mPFC) represented it when they recollected a target object's location relative to their self-body. During recollection, task-dependent functional connectivity increased between the two areas implying exchange of self-location and target location signals between the HPC and mPFC. Together, the object-based cognitive map, whose coherent spatial information could be formed by objects, may be recruited in the HPC and mPFC for complementary functions during navigation, which may generalize to other aspects of cognition, such as navigating social interactions., (© The Author(s) 2020. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Aging is associated with cognitive decline, specifically in episodic memory. However, there are large individual differences in the extent of this decline and previous research suggests that these are associated with differences in executive functioning (EF). These EF differences, and associated differences in the encoding and retrieval of episodic information, have been linked to differences in the activation of particular brain regions. The "encoding/retrieval flip" (E/R flip) framework assumes deactivation and activation of specific brain regions during successful encoding and retrieval, respectively. The present study assessed whether this framework can be used to explain EF-based individual differences in memory performance of young and older participants. Young adults (N = 19) and older adults (N = 39) performed an incidental semantic encoding and memory recognition task in an fMRI setting, focusing on brain regions that show the E/R flip. The association between an index of EF and fMRI activity in brain regions showing the E/R flip was tested in each age group. EF predicted E/R flip activity in the older, but not young adults. These findings underscore the importance of individual differences in ageing research and provide empirical evidence for the association between EF and the E/R flip., (Copyright © 2020 The Author(s). Published by Elsevier Inc. All rights reserved.)

Background: By 2050, the prevalence of Alzheimer's disease (AD) in the United States is predicted to reach 13.8 million. Despite worldwide research efforts, a cure for AD has not been identified. Thus, it is critical to identify preventive strategies that can reduce the risk of or delay the onset of AD. Physical activity (PA) has potential in this regard. This randomized clinical trial aims to (a) test the causal relationship between PA and AD-associated cognitive function for persons with a family history of AD (FH+), (b) determine the moderating role of apolipoprotein epsilon 4 (APOE4) carrier status on cognition, and (c) assess cerebral structure, cerebral function, and putative biomarkers as mediators of the effects of PA on cognition., Methods: We are recruiting cognitively normal, middle aged (40-65 years) sedentary adults with FH+. Participants are randomly assigned to a 12-month PA intervention for 3 days/week or to a control group maintaining their normal lifestyle. Saliva samples are taken at pre-test to determine APOE genotype. At pre-, mid-, and post-tests, participants complete a series of cognitive tests to assess information-processing speed, verbal and visual episodic memory, constructional praxis, mnemonic discrimination, and higher-order executive functions. At pre- and post-tests, brain imaging and blood biomarkers are assessed., Discussion: We hypothesize that 1) the PA group will demonstrate improved cognition compared with controls; 2) PA-derived cognitive changes will be moderated by APOE4 status; and 3) PA-induced changes in neural and blood biomarkers will contribute to cognitive changes and differ as a function of APOE4 status. Our results may provide important insights into the potential of PA to preserve neurocognitive function in people with a heightened risk of AD due to FH+ and as moderated by APOE4 status. By using sophisticated analytic techniques to assess APOE as a moderator and neurobiological mechanisms as mediators across trajectories of cognitive change in response to PA, we will advance our understanding of the potential of PA in protecting against AD., Trial Registration: ClinicalTrials.gov NCT03876314. Registered March 15, 2019.

Objective: The Everyday Cognition (ECog) scales measure cognitively based across domains of everyday abilities that are affected early in the course of neurodegenerative disorders such as Alzheimer's disease. However, the degree to which the ECog may be differentially influenced by ethnic/racial background is unknown. This study evaluates measurement invariance of the ECog across non-Hispanic White (NHW), Black, and Hispanic individuals., Methods: Participants included 1177 NHW, 243 Black, and 216 Hispanic older adults from the UC Davis Alzheimer's Disease Center Cohort who had an ECog. Differential item functioning (DIF) for each ECog domain was evaluated separately for Black and Hispanic participants compared to NHW participants. An iterative multiple group confirmatory factor analysis approach for ordinal scores was used to identify items whose measurement properties differed across groups and to adjust scores for DIF. Adjusted scores were then evaluated to test whether they were more strongly associated with cognitive function (concurrent and longitudinal change in cognition) and brain volumes (measured by brain imaging)., Results: Varying levels, patterns, and impacts of DIF were found across domains and groups. However, the impact of DIF was relatively small, and DIF effects on scores generally were less than one-half standard error of measurement. There were no meaningful differences in associations with cognition and brain injury between DIF adjusted and unadjusted scores., Conclusions: Varying patterns of DIF were observed across the Black and Hispanic participants across select ECog domains. Overall, DIF effects were relatively small and did not change the relationship between the ECog and other indicators of disease.

Adolescence may mark a sensitive period for the development of higher-order cognition through enhanced plasticity of cortical circuits. At the same time, animal research indicates that pubertal hormones may represent one key mechanism for closing sensitive periods in the associative neocortex, thereby resulting in decreased plasticity of cortical circuits in adolescence. In the present review, we set out to solve some of the existing ambiguity and examine how hormonal changes associated with pubertal onset may modulate plasticity in higher-order cognition during adolescence. We build on existing age-comparative cognitive training studies to explore how the potential for change in neural resources and behavioral repertoire differs across age groups. We review animal and human brain imaging studies, which demonstrate a link between brain development, neurochemical mechanisms of plasticity, and pubertal hormones. Overall, the existent literature indicates that pubertal hormones play a pivotal role in regulating the mechanisms of experience-dependent plasticity during adolescence. However, the extent to which hormonal changes associated with pubertal onset increase or decrease brain plasticity may depend on the specific cognitive domain, the sex, and associated brain networks. We discuss implications for future research and suggest that systematical longitudinal assessments of pubertal change together with cognitive training interventions may be a fruitful way toward a better understanding of adolescent plasticity. As the age of pubertal onset is decreasing across developed societies, this may also have important educational and clinical implications, especially with respect to the effects that earlier puberty has on learning., Competing Interests: Declaration of Competing Interest The authors declare no conflict of interest., (Copyright © 2020 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

The impact of linguistic distance or the relatedness between two languages, on bilinguals' episodic memory performance and verbal fluency is an understudied area. Thus, the purpose of this study was to determine if differences in linguistic distances have differential effects on these abilities. Measures of episodic recognition, categorical fluency, and global cognitive functioning were also considered in the analyses. Two matched samples with participants living and educated in Sweden were drawn from the Betula Prospective Cohort Study. Results showed that bilinguals who speak linguistically similar languages (Swedish and English), performed significantly better than monolinguals on both episodic memory recall and letter fluency, while bilinguals who speak two languages that are more distant (Swedish and Finnish), showed no advantages compared to their monolingual counterparts. For both tasks, however, a linear trend was observed indicative of better performance for the Swedish-English group compared to the Finnish-Swedish group, and for the Swedish-Finnish group compared to the monolinguals group. As expected, no differences between groups were found in any of the other cognitive tasks. Overall, results suggest that the impact of linguistic distances should be explored in more detail in the future., (© 2019 Scandinavian Psychological Associations and John Wiley & Sons Ltd.)

Human memory is strongly influenced by brain states occurring before an event, yet we know little about the underlying mechanisms. We found that activity in the cingulo-opercular network (including bilateral anterior insula [aI] and anterior prefrontal cortex [aPFC]) seconds before an event begins can predict whether this event will subsequently be remembered. We then tested how activity in the cingulo-opercular network shapes memory performance. Our findings indicate that prestimulus cingulo-opercular activity affects memory performance by opposingly modulating subsequent activity in two sets of regions previously linked to encoding and retrieval of episodic information. Specifically, higher prestimulus cingulo-opercular activity was associated with a subsequent increase in activity in temporal regions previously linked to encoding and with a subsequent reduction in activity within a set of regions thought to play a role in retrieval and self-referential processing. Together, these findings suggest that prestimulus attentional states modulate memory for real-life events by enhancing encoding and possibly by dampening interference from competing memory substrates., (© The Author(s) 2019. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permission@oup.com.)

Background: Fruits and vegetables are generally rich in antioxidants such as carotenoids. Consumption of carotenoids is expected to have benefits on cognitive functions in humans. However, previous randomized controlled trials (RCT) using carotenoids have reported inconsistent results. Therefore, this systematic review (SR) aimed to summarize the effect of carotenoid intake on cognitive functions in humans., Method: PubMed, Cochrane Library, Web of Science, and PsychoINFO were searched for research papers on carotenoid intake with the criteria that 1) oral carotenoid intake was evaluated using RCTs, 2) participants were healthy young, middle-aged, or older, and 3) cognitive functions were measured using RCTs., Results: Five studies using lutein and two studies using astaxanthin met the inclusion criteria. Consumption of lutein and its isomer showed consistent results in selective improvement of visual episodic memory in young and middle-aged adults while inhibition was observed in middle-aged and older adults. One of the two included astaxanthin studies reported a significant improvement of verbal episodic memory performance in middle-aged adults., Conclusion: This SR showed that the 10 mg lutein per day for twelve months can lead to improvement of cognitive functions. Due to the small number of studies, it is difficult to conclude whether astaxanthin would have a positive effect on cognitive functions., Competing Interests: This study was a corroborative study between Institute of Development, Aging, and Cancer (IDAC), Tohoku University and Lion Corporation. supported by Lion Corporation. R.N and R.K received research grants from Lion Corporation. T.S., E.K, H.T., M.M., A.U., and M.A are full-time employees of Lion Corporation. The company policy was not involved in the study design, collection, analysis, interpretation of data, or writing of the manuscript. The authors declare that they have no other competing interests.

Objective: To examine prospective associations of clinically relevant depressive symptoms with cognitive functions and rates of cognitive decline among Chinese adults aged 45 years and older., Methods: Data was from the China Health and Retirement Longitudinal Study (CHARLS) with a follow-up of 4 years. Based on the Chinese version of 10-item Center for Epidemiologic Studies Depression Scale (CESD-10), clinically relevant depressive symptoms were defined with a CESD-10 score≥10 points. Cognitive functions were measured in three domains: episodic memory, mental status and global cognition. Linear mixed models were used to assess the associations between clinically relevant depressive symptoms and cognitive functions., Results: A total of 7335 participants (50.10% men; mean age: 57.47) were included in analyses. Participants with clinically relevant depressive symptoms showed poorer episodic memory (β=-0.35; 95% CI:-0.41, -0.29), mental status (β=-0.48; 95% CI: -0.57, -0.39), and global cognition (β=-0.82; 95% CI: -0.94, -0.70) during the follow-up. Compared with counterparts, rates of decline in episodic memory, mental status, and global cognition increased by 0.04 (β=0.04; 95% CI: 0.02, 0.06), 0.06 (β=0.06; 95% CI: 0.02, 0.09) and 0.11 (β=0.11; 95% CI: 0.06, 0.15) units per year in participants with clinically relevant depressive symptoms., Limitations: A major limitation is that clinically relevant depressive symptoms were assessed by a screening tool and the follow-up was short., Conclusion: More severe clinically relevant depressive symptoms were associated with poorer cognitive functions and moderately faster cognitive decline in episodic memory, mental status and global cognition in middle-aged and elderly Chinese adults., Competing Interests: Declaration of Competing Interest The authors declare that there is no conflict of interest., (Copyright © 2019. Published by Elsevier B.V.)

There is good evidence that cocoa flavonoids can acutely improve cognitive function in humans, possibly via mechanisms such as increased cerebral blood flow. To date, much of the evidence is based on measures of executive function with extracts and cocoa-based interventions with a high flavonoid content. The aim of the present study was to explore whether benefits to episodic verbal memory and mood are observed two hours post consumption of a commercially available dark chocolate (DC) bar relative to a 35 g white chocolate bar (WC). Ninety-eight healthy young adults ( n = 57 females) aged 18-24 years consumed either a 35 g DC bar or a calorie-matched low flavonoid WC bar. Verbal episodic memory and mood were assessed pre consumption and 2 h post consumption. An ANOVA analysis showed that the DC was associated with better verbal memory performance for several outcome measures of the Rey Auditory Verbal Learning Test relative to the WC, however, there were no effects on mood. These findings lend support to the notion that everyday available portions of dark chocolate can confer benefits to the brain in healthy consumers.

Some people aged 80 years and older are "memory SuperAgers" (SAs), that is, they have the episodic memory of a sexagenarian. In a sample of 208 non-demented adults, we found that 12% were SAs. A total of 101 participants completed the 4-year study; of this subsample, 10.9% were stable SAs and 61.3% stable non-SAs across all assessments. The SA phenotype is conducive to further research., (© 2019 The Institute of Psychology, Chinese Academy of Sciences and John Wiley & Sons Australia, Ltd.)

Higher cognitive functioning is supported by adaptive reconfiguration of large-scale functional brain networks. Cognitive control (CC), which plays a vital role in flexibly guiding cognition and behavior in accordance with our goals, supports a range of executive functions via distributed brain networks. These networks process information dynamically and can be represented as functional connectivity changes between network elements. Using graph theory, we explored context-dependent network reorganization in 56 healthy adults performing fMRI tasks from two cognitive domains that varied in CC and episodic-memory demands. We examined whole-brain modular structure during the DPX task, which engages proactive CC in the frontal-parietal cognitive-control network (FPN), and the RiSE task, which manipulates CC demands at encoding and retrieval during episodic-memory processing, and engages FPN, the medial-temporal lobe and other memory-related networks in a context dependent manner. Analyses revealed different levels of network integration and segregation. Modularity analyses revealed greater brain-wide integration across tasks in high CC conditions compared to low CC conditions. Greater network reorganization occurred in the RiSE memory task, which is thought to require coordination across multiple brain networks, than in the DPX cognitive-control task. Finally, FPN, ventral attention, and visual systems showed within network connectivity effects of cognitive control; however, these cognitive systems displayed varying levels of network reorganization. These findings provide insight into how brain networks reorganize to support differing task contexts, suggesting that the FPN flexibly segregates during focused proactive control and integrates to support control in other domains such as episodic memory.

HIV-1-associated neurocognitive disorders (HAND), characterized by alterations in the core components of cognitive function and age-related disease progression, persist in the post-cART era. However, the neurobehavioral mechanisms that mediate alterations in the core components of cognitive function and the progression of neurocognitive impairments have yet to be systematically evaluated. To address this knowledge gap, statistical mediation analysis was assessed, providing a critical opportunity to empirically evaluate putative neurobehavioral mechanisms underlying HAND. Neurocognitive assessments, conducted in HIV-1 transgenic (Tg) and control animals across the functional lifespan (i.e., Postnatal Day (PD) 30 to PD 600), tapped multiple cognitive domains including preattentive processes, learning, sustained attention, and long-term episodic memory. Three longitudinal mediation models were utilized to assess whether deficits in preattentive processes mediate alterations in learning, sustained attention and/or long-term episodic memory over time. Preattentive processes partially mediated the relationship between genotype and learning, genotype and sustained attention, and genotype and long-term episodic memory across the functional lifespan, explaining between 44% and 58% of the HIV-1 transgene effect. Understanding the neurobehavioral mechanisms mediating alterations in HAND may provide key targets for the development of a diagnostic biomarker, novel therapeutics, and cure/restoration strategies., (Copyright © 2019 Elsevier B.V. All rights reserved.)

It is unclear whether episodic memory is an appropriate descriptor of the cognitive continuum in mild cognitive impairment (MCI). Here, we investigated the ability of episodic memory to track cognitive changes in patients with MCI with biomarker evidence of Alzheimer's disease (AD). We examined 387 MCI amyloid-positive subjects, cognitively staged as "early" or "late" on the basis of episodic memory impairment. Cross-sectional and longitudinal comparisons between these 2 groups were performed for each amyloid, tau, and neurodegeneration (AT(N)) profile. Cross-sectional analyses indicate that "early" MCI represents a transitional phase between normal cognition and "late" MCI in the AD biomarker pathway. After adjusting by confounders and levels of A, T, and (N), "late" MCI progressed significantly faster than "early" MCI only in profiles with both abnormal amyloid and tau markers (A+T+(N)- p < 0.05, A+T+(N)+ p < 0.001). Episodic memory staging is useful for describing symptoms in prodromal AD and complements the AT(N) profiles. Our findings might have implications for the Numeric Clinical staging scheme of the National Institute on Aging and Alzheimer's Association research framework., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: Episodic memory starts to decline very early in the development of Alzheimer's disease (AD). Subtle impairments in memory binding may be detected in mild cognitive impairment (MCI). This study aims to examine the psychometric properties of the Chinese version of the memory binding test (MBT)., Methods: One hundred and sixty-four subjects (26 individuals with AD, 67 individuals with amnestic MCI (aMCI), 30 individuals with subjective cognitive impairment (SCI), and 41 cognitively normal elderly individuals (NC)) participated in the study. Twenty-two subjects repeated the assessment of the MBT within 6 weeks (± 2 weeks). Pearson correlation was used to calculate the convergent validity. The test--retest reliability was determined by the calculation of the intraclass correlation coefficient (ICC). Discriminative validity was calculated to evaluate the receiver-operating characteristic curves. The optimal index was chosen by comparing the area under the curve for specificity and sensitivity ≥ 0.80. The optimal cutoff score of the index was chosen to maximize the sum of sensitivity and specificity., Results: The absolute value of the convergent validity of the direct indexes of MBT ranged from 0.443 to 0.684. The ICC for each of direct indexes was 0.887-0.958. Total delayed paired recall (TDPR) was the optimal index for discriminating aMCI from NC. The cutoff score for TDPR was ≤25 to distinguish aMCI from NC (sensitivity = 0.896, specificity = 0.707)., Conclusion: The Chinese version of MBT is a valid and reliable instrument to detect MCI.