Elevated Blood Homocysteine Increases the Risk of Incident Motoric Cognitive Risk Syndrome: A Two-Cohort Study.

BACKGROUND: Motoric Cognitive Risk (MCR) syndrome, a predementia syndrome characterized by cognitive complaints and slow gait, may have an underlying vascular etiology. Elevated blood levels of homocysteine, a known vascular risk factor, have been linked to physical and cognitive decline in older adults, though the relationship with MCR is unknown. We aimed to identify the association between homocysteine and MCR risk. METHODS: We examined the association between baseline homocysteine levels and incident MCR using Cox proportional hazard models in 1826 community-dwelling older adults (55% women) from 2 cohorts (Einstein Aging Study [EAS] and Quebec Longitudinal Study on Nutrition and Successful Aging [NuAge]). We calculated hazard ratios (HR) with 95% confidence intervals (CI), for each cohort as well as stratified by sex and vascular disease/risk factors. RESULTS: Median follow-up time was 2.2 years in EAS and 3.0 years in NuAge. Individuals with elevated baseline homocysteine levels (>14 µmol/L) had a significantly higher risk of incident MCR compared to those with normal levels in NuAge (HR 1.41, 95% CI: 1.01-1.97, p = .04), after adjusting for covariates. Our exploratory stratified analyses found that these associations were significant only in men with vascular disease/risk factors. CONCLUSIONS: Higher blood homocysteine levels are associated with an increased risk of developing MCR in older adults, particularly in men with vascular disease or vascular risk factors.

The Effects of Mind-Wandering, Cognitive Load, and Task Engagement on Working Memory Performance in Remote Online Experiments.

Recent changes in environments from in-person to remote present several issues for work, education, and research, particularly related to cognitive performance. Increased distraction in remote environments may lead to increases in mind-wandering and disengagement with tasks at hand, whether virtual meetings, online lectures, or psychological experiments. The present study investigated mind-wandering and multitasking effects during working memory tasks in remote and in-person environments. In two experiments, participants completed a working memory task with varied cognitive load during a secondary task. After each working memory trial, participants reported their mind-wandering during that trial. Some participants completed the procedures in-person, while others completed the procedures remotely. Overall, remote participants reported significantly more mind-wandering and poorer secondary task performance than in-person participants, but this pattern was not reflected in working memory accuracy. Both groups exhibited similar multitasking effects on performance. Additional analyses found that for remote participants, task engagement better predicted working memory performance than either cognitive load or mind-wandering rates but did not indicate a tradeoff in resources between tasks. Together, these results demonstrate the importance of considering multiple metrics when assessing performance and illustrate that making assumptions about the equivalence of remote and in-person work is a risky proposition.

Secondary task engagement drives the McCabe effect in long-term memory.

Processing that occurs while information is held in working memory is critical in long-term retention of that information. One counterintuitive finding is that the concurrent processing required during complex span tasks typically impairs immediate memory, while also leading to improved delayed memory. One proposed mechanism for this effect is retrieval practice that occurs each time memory items are displaced to allow for concurrent processing during complex span tasks. Other research has instead suggested that increased free time during complex span procedures underlies this effect. In the present study, we presented participants with memory items in simple, complex, and slow span tasks and compared their performance on immediate and delayed memory tests. We found that how much a participant engaged with the secondary task of the complex span task corresponded with how strongly they exhibited a complex span boost on delayed memory performance. We also probed what participants were thinking about during the task, and found that participants' focus varied depending both on task type and secondary task engagement. The results support repeated retrieval as a key mechanism in the relationship between working memory processing and long-term retention. Further, the present study highlights the importance of variation in individual cognitive processing in predicting long-term outcomes even when objective conditions remain unchanged.

Is there a role of creativity in the relationship between working memory consolidation and long-term memory?

While holding items in working memory has been shown to improve delayed long-term recall, the mechanisms underlying this relationship remain unclear. One potential mechanism is working memory consolidation, which may facilitate the formation of novel associations between items during learning and lead to improved memory search at delayed retrieval. Forming novel associations via consolidation may share mechanisms with creative ability. The present research aims to explore how an individual's creativity relates to the relationship between working memory consolidation and long-term memory. In Experiment 1, participants completed a stimulus identification task that manipulated the need for consolidation followed by a surprise delayed recognition task and measures of objective and self-reported creativity. While creativity scores were correlated with general performance on memory tasks, this effect was not related to working memory consolidation. In Experiment 2, participants were induced into either a creative or a non-creative state prior to completing the stimulus identification and delayed recognition tasks. Performance on these tasks was not significantly different between the groups and was again unrelated to working memory consolidation. The results of these two experiments suggest that creativity is not related to the mechanism underlying the effect of working memory consolidation on delayed recognition.

Examining the relationship between working memory consolidation and long-term consolidation.

An emerging area of research is focused on the relationship between working memory and long-term memory and the likely overlap between these processes. Of particular interest is how some information first maintained in working memory is retained for longer periods and eventually preserved in long-term memory. The process of stabilizing transient memory representations for lasting retention is referred to as consolidation in both the working memory and long-term memory literature, although these have historically been viewed as independent constructs. The present review aims to investigate the relationship between working memory consolidation and long-term memory consolidation, which both have rich, but distinct, histories. This review provides an overview of the proposed models and neural mechanisms of both types of consolidation, as well as clinical findings related to consolidation and potential approaches for the manipulation of consolidation. Finally, two hypotheses are proposed to explain the relationship between working memory consolidation and long-term memory consolidation.

Working memory consolidation improves long-term memory recognition.

Recent research has found that maintaining an item in working memory improves subsequent long-term memory performance. The present study explored the role of working memory consolidation in long-term recognition. Participants completed a stimuli-identification task followed by a surprise delayed recognition task. Participants first identified which one of four stimuli matched a target stimulus. The target item was presented either just before or simultaneously with the response set. This manipulation requires the participant to consolidate the target into working memory in the before presentation condition but not in the simultaneous presentation condition. Delayed recognition for the target items was then tested. Despite a slight performance advantage for the simultaneous presentation condition in the stimuli-identification task, long-term recognition performance was considerably better for target items presented in the before presentation condition. These results suggest that consolidation into working memory and not simply attending to an item improves long-term memory performance. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Gray Matter Volume Covariance Networks, Social Support, and Cognition in Older Adults.

OBJECTIVE: We examined the neural substrates of social support in older adults. Social support is associated with better outcomes in many facets of aging-including cognitive and functional health-but the underlying neural substrates remain largely unexplored. METHODS: Voxel-based morphometry and multivariate statistics were used to identify gray matter volume covariance networks associated with social support in 112 older adults without dementia (M age = 74.6 years, 50% female), using the Medical Outcomes Study Social Support Survey. RESULTS: A gray matter network associated with overall social support was identified and included prefrontal, hippocampal, amygdala, cingulate, and thalamic regions. A gray matter network specifically associated with tangible social support (e.g., someone to help you if you were confined to bed) was also identified, included prefrontal, hippocampal, cingulate, insular, and thalamic regions, and correlated with memory and executive function. DISCUSSION: Gray matter networks associated with overall and tangible social support in this study were composed of regions previously associated with memory, executive function, aging, and dementia. Longitudinal research of the interrelationships between social support, brain structure, and cognition is needed, but strengthening social support may represent a new path toward improving cognition in aging that should be explored.

Multisensory Integration Predicts Balance and Falls in Older Adults.

BACKGROUND: Effective integration of concurrent sensory information is crucial for successful locomotion. This study aimed to determine the association of multisensory integration with mobility outcomes in aging. METHODS: A total of 289 healthy older adults (mean age 76.67 ± 6.37 years; 53% female participants) participated in a visual-somatosensory simple reaction time task. Magnitude of multisensory effects was assessed using probability models, and then categorized into four multisensory integration classifications (superior, good, poor, or deficient). Associations of multisensory integration with falls and balance (unipedal stance) were tested at cross-section and longitudinally using Cox proportional hazards models. RESULTS: At baseline, the prevalence of falls in the previous year was 24%, and 52% reported an incident fall over a mean follow-up period of 24 ± 17 months. Mean unipedal stance time was 15 ± 11 seconds. Magnitude of multisensory integration was a strong predictor of balance performance at cross-section (ß = 0.11; p < .05). Of the cohort, 31% had superior, 26% had good, 28% had poor, and 15% had deficient multisensory effects. Older adults with superior multisensory integration abilities were significantly less likely to report a fall in the past year (17%), compared to the rest of the cohort (28%; χ2 = 4.01; p = .04). Magnitude of multisensory integration was an incremental predictor of incident falls (adjusted hazard ratio = 0.24; p = .01), over and above balance and other known fall risk factors. CONCLUSIONS: Our study highlights the clinical relevance of multisensory integration in aging; worse visual-somatosensory integration is associated with worse balance and increased risk of incident falls.

Mental Fatigability and Heart Rate Variability in Mild Cognitive Impairment.

OBJECTIVES: Adaptive physiological stress regulation is rarely studied in mild cognitive impairment (MCI). Here we targeted mental fatigability (MF) as a determinant of altered high frequency heart rate variability (HF-HRV) reactivity in individuals with MCI, and examined frontobasal ganglia circuitry as a neural basis supporting the link between MF and HF-HRV reactivity. METHODS: We measured mental fatigability and HF-HRV during a 60-minute cognitive stress protocol in 19 individuals with MCI. HF-HRV responses were modeled using a quadratic equation. Resting state functional connectivity of intra- and inter-network frontobasal ganglia circuitry was assessed using blood-oxygen-level-dependent magnetic resonance imaging among seven of the participants. RESULTS: Lower MF was associated with faster and greater rebound in U-shape HF-HRV reactivity, which linked to a stronger connectivity between right middle frontal gyrus and left putamen. CONCLUSIONS: Results suggest that MF may contribute to abnormal physiological stress regulation in MCI, and fronto basal ganglia circuitry may support the link.

Generation of Scalable, Metallic High-Aspect Ratio Nanocomposites in a Biological Liquid Medium.

The goal of this protocol is to describe the synthesis of two novel biocomposites with high-aspect ratio structures. The biocomposites consist of copper and cystine, with either copper nanoparticles (CNPs) or copper sulfate contributing the metallic component. Synthesis is carried out in liquid under biological conditions (37 °C) and the self-assembled composites form after 24 hr. Once formed, these composites are highly stable in both liquid media and in a dried form. The composites scale from the nano- to micro- range in length, and from a few microns to 25 nm in diameter. Field emission scanning electron microscopy with energy dispersive X-ray spectroscopy (EDX) demonstrated that sulfur was present in the NP-derived linear structures, while it was absent from the starting CNP material, thus confirming cystine as the source of sulfur in the final nanocomposites. During synthesis of these linear nano- and micro-composites, a diverse range of lengths of structures is formed in the synthesis vessel. Sonication of the liquid mixture after synthesis was demonstrated to assist in controlling average size of the structures by diminishing the average length with increased time of sonication. Since the formed structures are highly stable, do not agglomerate, and are formed in liquid phase, centrifugation may also be used to assist in concentrating and segregating formed composites.