Associations between hippocampal morphology, diffusion characteristics, and salivary cortisol in older men

The longitudinal association between individual differences in recall of positive specific autobiographical memories and daily cortisol

The present study examines the longitudinal association between cortisol (dys)regulation - mean cortisol awakening response (CAR) and area under the curve with respect to ground (AUCg) for total daily cortisol - and autobiographical memory. 135 participants (mean age at baseline = 16.1; Females = 78.5 %) provided cortisol samples (T1). Seven months later participants retrieved autobiographical memories cued by positive and negative words (T2). Four years subsequently, participants provided cortisol samples again (T3). The retrieval of more specific memories cued by positive words, but not negative words, was associated with higher AUCg four years later, independent of sex, recent life stressors and self-reported negative self-related cognitions. There were no associations between CAR and autobiographical memory. Neither AUC nor CAR at T1 predicted subsequent autobiographical memory abilities. People who retrieve more positive specific memories may be more likely to imagine and seek out positive experiences and this may be associated with higher cortisol levels.

Current State of Saliva Biomarkers for Aging and Alzheimer's Disease

INTRODUCTION

Aging is the primary risk factor for major human pathologies, including cancer, diabetes, cardiovascular diseases, and neurodegenerative diseases such as Alzheimer's Disease (AD). AD is a progressive degenerative disorder of the brain and is the most common form of dementia.

METHODS

To-date no simple, inexpensive and minimally invasive procedure is available to confirm with certainty the early diagnosis of AD prior to the manifestations of symptoms characteristic of the disease. Therefore, if population screening of individuals is to be performed, easily accessible tissues would need to be used for a diagnostic test that would identify those who exhibit altered or aberrant aging profiles that may be indicative of AD risk, so that they can be prioritized for primary prevention. This need for minimally invasive tests could be achieved by targeting saliva, since it is now well recognized that many aging diseases including AD are associated with peripheral biomarkers that are not only restricted to pathology and biomarkers within the brain.

RESULTS

Therefore, the aim of this review is to summarize some of the main findings of salivary biomarkers of aging and AD; including various proteins, metabolites, and alterations to DNA and miRNA. The future of healthy aging resides in innovative platforms, biosensors and point-of-care devices that can extract real time information on the health status of an individual. Those platforms may be achieved through the development and validation of novel biomarkers of health using saliva which, although being the least explored for biomedical purposes, has the distinct advantage that it can be self-collected in a non-invasive manner.

Neurobiological mechanisms underlying sex-related differences in stress-related disorders: Effects of neuroactive steroids on the hippocampus

Men and women differ in their vulnerability to a variety of stress-related illnesses, but the underlying neurobiological mechanisms are not well understood. This is likely due to a comparative dearth of neurobiological studies that assess male and female rodents at the same time, while human neuroimaging studies often don't model sex as a variable of interest. These sex differences are often attributed to the actions of sex hormones, i.e. estrogens, progestogens and androgens. In this review, we summarize the results on sex hormone actions in the hippocampus and seek to bridge the gap between animal models and findings in humans. However, while effects of sex hormones on the hippocampus are largely consistent in animals and humans, methodological differences challenge the comparability of animal and human studies on stress effects. We summarise our current understanding of the neurobiological mechanisms that underlie sex-related differences in behavior and discuss implications for stress-related illnesses.

Theory of mind and psychosocial characteristics in older men

The extent to which early-life cognitive ability shapes individuals' social functioning throughout life, in the context of later-life factors, is unknown. We investigated performance on the Faux Pas test (FP) in relation to psychosocial characteristics and childhood intelligence scores in 90 healthy older men. FP performance was associated with close social network size but not social contact, social support, or loneliness when accounting for both childhood and later-life intelligence, affect, personality, and sociodemography. We add to a growing literature on associations between theory of mind and intelligence, affect, and personality. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Healthy cognitive ageing in the Lothian Birth Cohort studies: marginal gains not magic bullet

In the face of shifting demographics and an increase in human longevity, it is important to examine carefully what is known about cognitive ageing, and to identify and promote possibly malleable lifestyle and health-related factors that might mitigate age-associated cognitive decline. The Lothian Birth Cohorts of 1921 (LBC1921, n = 550) and 1936 (LBC1936, n = 1091) are longitudinal studies of cognitive and brain ageing based in Scotland. Childhood IQ data are available for these participants, who were recruited in later life and then followed up regularly. This overview summarises some of the main LBC findings to date, illustrating the possible genetic and environmental contributions to cognitive function (level and change) and brain imaging biomarkers in later life. Key associations include genetic variation, health and fitness, psychosocial and lifestyle factors, and aspects of the brain's structure. It addresses some key methodological issues such as confounding by early-life intelligence and social factors and emphasises areas requiring further investigation. Overall, the findings that have emerged from the LBC studies highlight that there are multiple correlates of cognitive ability level in later life, many of which have small effects, that there are as yet few reliable predictors of cognitive change, and that not all of the correlates have independent additive associations. The concept of marginal gains, whereby there might be a cumulative effect of small incremental improvements across a wide range of lifestyle and health-related factors, may offer a useful way to think about and promote a multivariate recipe for healthy cognitive and brain ageing.