The Missing Link in Antiamyloid Therapy.

Alzheimer's disease (AD) impacts millions of elderly adults worldwide causing cognitive decline and severe deterioration of activities of daily life. The popular causal hypotheses for several decades include beta-amyloid (Aβ) deposition and tau hyperphosphorylation. AD research and more than 34% of clinical trials in AD are based on these two hypotheses.

Multimodal neuroimaging biomarkers and subtle cognitive decline in a population-based cohort without dementia.

Background: The relationship between subtle cognitive decline and Alzheimer's disease (AD) pathology as measured by biomarkers in settings outside of specialty memory clinics is not well characterized.

Objective: To investigate how subtle longitudinal cognitive decline relates to neuroimaging biomarkers in individuals drawn from a population-based study in an economically depressed, small-town area in southwestern Pennsylvania, USA.

Methods: A subset of participants without dementia (N = 115, age 76.

Reactions of clinical neuropsychologists to the Alzheimer's Association workgroup's draft diagnostic and staging criteria for Alzheimer's disease.

Background: An Alzheimer's Association (AA) workgroup published criteria for the diagnosis and staging of Alzheimer's disease (AD). To date, there have not been empirical investigations of professionals' opinions regarding the AA criteria for AD.

Objective: Our goal was to survey clinical neuropsychologists with expertise in dementia about these criteria.

The importance of cognitive correlates of plasma amyloid-β 42/40.

This commentary focuses on the clinical utility of plasma amyloid-β (Aβ) 42/40 to detect semantic intrusion errors in amnestic mild cognitive impairment, as investigated Curiel Cid et al. in a recent issue of the . This commentary highlights the importance of testing the sensitivity of plasma Aβ to clinical symptoms in the quest to develop a comprehensive definition of AD that incorporates both biological precursors and clinical consequences.

Perivascular space burden interacts with APOE-ε4 status on cognition in older adults.

Enlarged perivascular spaces (ePVS) may adversely affect cognition. Little is known about how basal ganglia ePVS interact with apolipoprotein (APOE)-ε4 status. Vanderbilt Memory and Aging Project participants (n = 326, 73 ± 7, 59% male) underwent 3 T brain MRI at baseline to assess ePVS and longitudinal neuropsychological assessments.

Strategic filtering of high-energy visible light expands neural correlates of functional vision particularly in older participants.

In this study we assessed the neural correlates of functional vision while varying patterns of light filtration. Four filter conditions used relatively flat filtering across the visible spectrum while one filter was a step filter that selectively absorbed violet light (wavelengths below about 415 nm). Neural effects were quantified by measuring the BOLD response ((T2*-based fMRI) while subjects performed a challenging visual task (judging gap direction in Landolt Cs that randomly varied in size).

Physical activity moderates the association between executive function and functional connectivity in older adults.

Recent evidence suggests that physical activity may influence the functional connectivity of the aging brain. The purpose of this study was to examine the influence of physical activity on the association between executive function and functional connectivity of key brain networks and graph theory metrics in community-dwelling older adults. Participants were 47 older adults (M = 73 years; SD = 5.

Mean arterial pressure, fitness, and executive function in middle age and older adults.

Previous literature suggests that higher fitness is related to better executive function in older adulthood, but the mechanisms underlying this association are poorly understood. While many studies have focused on these associations in older adulthood, recent evidence suggests the importance of cardiorespiratory fitness (CRF) and long-term blood pressure control on cognitive functioning. The purpose of the current study was to examine whether mean arterial pressure (MAP) mediated the association between CRF and executive function in middle age and older adults.

Evidence for exercise-related plasticity in functional and structural neural network connectivity.

The number of studies investigating exercise and cardiorespiratory fitness (CRF)-related changes in the functional and structural organization of brain networks continues to rise. Functional and structural connectivity are critical biomarkers for brain health and many exercise-related benefits on the brain are better represented by network dynamics. Here, we reviewed the neuroimaging literature to better understand how exercise or CRF may facilitate and maintain the efficiency and integrity of functional and structural aspects of brain networks in both younger and older adults.

The Relations Between Physical Activity Level, Executive Function, and White Matter Microstructure in Older Adults.

The population of older adults is increasing, indicating a need to examine factors that may prevent or mitigate age-related cognitive decline. The current study examined whether microstructural white matter characteristics mediated the relation between physical activity and executive function in older adults without any self-reported psychiatric and neurological disorders or cognitive impairment (N = 43, mean age = 73 y). Physical activity was measured by average intensity and number of steps via accelerometry.

Frailty and Cognitive Function in Older Adults: A Systematic Review and Meta-Analysis of Cross-Sectional Studies.

The relationship between cognitive function and frailty among older adults is a growing area of research due to the implications of cognitive and physical decline for functional independence in late life. Multiple studies demonstrate a meaningful relationship between these two factors, which together may constitute increased risk of negative health outcomes for older adults. The current analysis was conducted to 1) systematically review current evidence for differences in cognitive performance based on frailty status among older adults and provide quantitative evidence for the magnitude of this effect, and 2) assess the influence of demographic and methodological variables on this effect.

Exercise interventions do not impact brain volume change in older adults: a systematic review and meta-analysis.

Exercise interventions have been shown to positively impact cognitive function in older adults, but the mechanisms underlying the neuroprotective effects of exercise on the brain are not well understood. Here, we aimed to synthesize and quantitatively analyze the current literature on exercise interventions and brain volume change in older adults and to examine the impact of key demographic and intervention features as well as study quality. This study was pre-registered with PROSPERO (CRD42018091866).

Pre-Morbid IQ Moderates the Relationship between Cognitive Performance and Performance-Based Functional Status in Older Adults.

: The current study sought to evaluate the relationship between cognitive performance and Instrumental Activities of Daily Living (IADL) performance in a population of community dwelling older adults, and assess to what extent this relationship is moderated by cognitive reserve (Premorbid-IQ): 123 community-dwelling older adults completed a general cognitive assessment, a word-reading based premorbid-IQ estimate (PMIQE) measure, and the performance-based Direct Assessment of Functional Status, Revised (DAFS-R). Moderated regression analysis was used to assess the influence of PMIQE on the relationship between cognitive performance and IADLs.: There was a significant main effect of cognitive performance on IADLs, and no main effect of PMIQE on functional IADLs.

A Multi-method Investigation of the Personality Correlates of Functional Ability in Older Adults.

Objectives: This study evaluated the role of personality in predicting functional ability (FA) in older adults using self-report, collateral report, and performance-based measures of FA.

Methods: Participants included older adults (N = 131) who completed a personality measure (NEO-FFI), a self-report of FA (OARS ADL), and participated in a performance-based assessment of FA (DAFS-R). In addition, each participant had a collateral complete a collateral report of FA (OARS ADL).

Education Differentially Buffers Cognitive Performance in Black and White Older Adults.

Objectives: Given that black American older adults are more likely to have lower educational attainment and perform worse on cognitive tests than white Americans, we examined whether increased education would confer greater cognitive advantage to black Americans on measures of global and specific domains of cognitive function.

Methods: The sample included 522 community-dwelling older adults from a larger study. An analysis of covariance was conducted with race and education as between-participant factors and global cognition as the dependent variable.

Body mass index and its relation to neuropsychological functioning and brain volume in healthy older adults.

Obesity is a growing concern worldwide because of its adverse health effects, including its negative impact on cognitive functioning. This concern is especially relevant for older adults, who are already likely to experience some cognitive decline and loss of brain volume due to aging, (Gea et al., 2002).

TrkB signalling pathway mediates the protective effects of exercise in the diabetic rat retina.

Diabetic retinopathy is a leading cause of vision loss. Treatment options for early retinopathy are sparse. Exercise protects dying photoreceptors in models of retinal degeneration, thereby preserving vision.

Neuroprotective Effects of Voluntary Exercise in an Inherited Retinal Degeneration Mouse Model.

Purpose: Our previous investigations showed that involuntary treadmill exercise is neuroprotective in a light-induced retinal degeneration mouse model, and it may act through activation of tropomyosin-related kinase B (TrkB) receptors. This study investigated whether voluntary running wheel exercise can be neuroprotective in an inheritable model of the retinal degenerative disease retinitis pigmentosa (RP), rd10 mice.

Methods: Breeding pairs of rd10 and C57BL/6J mice were given free-spinning (active) or locked (inactive) running wheels.

Exercise and Cyclic Light Preconditioning Protect Against Light-Induced Retinal Degeneration and Evoke Similar Gene Expression Patterns.

To compare patterns of gene expression following preconditioning cyclic light rearing versus preconditioning aerobic exercise. BALB/C mice were preconditioned either by rearing in 800 lx 12:12 h cyclic light for 8 days or by running on treadmills for 9 days, exposed to toxic levels of light to cause light-induced retinal degeneration (LIRD), then sacrificed and retinal tissue harvested. Subsets of mice were maintained for an additional 2 weeks and for assessment of retinal function by electroretinogram (ERG).

Aerobic exercise protects retinal function and structure from light-induced retinal degeneration.

Aerobic exercise is a common intervention for rehabilitation of motor, and more recently, cognitive function (Intlekofer and Cotman, 2013; Wood et al., 2012). While the underlying mechanisms are complex, BDNF may mediate much of the beneficial effects of exercise to these neurons (Ploughman et al.