Myelin breakdown mediates age-related slowing in cognitive processing speed in healthy elderly men

Background

To assess the hypothesis that in a sample of very healthy elderly men selected to minimize risk for Alzheimer’s disease (AD) and cerebrovascular disease, myelin breakdown in late-myelinating regions mediates age-related slowing in cognitive processing speed (CPS).

Materials and methods

The prefrontal lobe white matter and the genu of the corpus callosum myelinate later in brain development (late-myelinating white matter; LMWM) and are more vulnerable to breakdown due to the effects of normal aging. An in vivo MRI biomarker of myelin integrity (transverse relaxation rates; R₂) of LMWM was obtained for 38 very healthy elderly adult men (mean age = 66.3 years; SD = 6.0; range = 55–76). To evaluate regional specificity, we also assessed a contrasting early-myelinating region (splenium of the corpus callosum; SWM), which primarily contains axons involved in visual processing. CPS was assessed using the Trail Making Test.

Results

LMWM R₂ and CPS measures were significantly correlated (r = .515, p = .0009), but no significant association between R₂ and CPS was detected in the splenium (p = .409). LMWM R₂, but not SWM R₂, was a significant mediator of the relationship between age and CPS (p = .037).

Conclusions

In this very healthy elderly sample, age-related slowing in CPS is mediated by myelin breakdown in highly vulnerable late-myelinating regions but not in the splenium.     

An unforgettable apple: Memory and attention for forbidden objects

Are we humans drawn to the forbidden? From jumbo-sized soft drinks to illicit substances, the influence of prohibited ownership on subsequent demand has made this question a pressing one. We know that objects that we ourselves own have a heightened psychological saliency, relative to comparable objects that are owned by others, but do these kinds of effects extend from self-owned to “forbidden” objects? To address this question, we developed a modified version of the Turk shopping paradigm in which “purchased” items were assigned to various recipients. Participants sorted everyday objects labeled as “self-owned”, “other-owned,” and either “forbidden to oneself” (Experiment 1) or “forbidden to everyone” (Experiment 2). Subsequent surprise recognition memory tests revealed that forbidden objects with high (Experiment 1) but not with low (Experiment 2) self-relevance were recognized as well as were self-owned objects, and better than other-owned objects. In a third and final experiment, we used event-related potentials (ERPs) to determine whether self-owned and self-forbidden objects, which showed a common memory advantage, are in fact treated the same at a neurocognitive–affective level. We found that both object types were associated with enhanced cognitive analysis, relative to other-owned objects, as measured by the P300 ERP component. However, we also found that self-forbidden objects uniquely triggered an enhanced response preceding the P300, in an ERP component (the N2) that is sensitive to more rapid, affect-related processing. Our findings thus suggest that, whereas self-forbidden objects share a common cognitive signature with self-owned objects, they are unique in being identified more quickly at a neurocognitive level.     

A Review of the Evidence for a Biological Basis for Snake Fears in Humans

The Psychological Record - Three types of evidence are considered for the view that the propensity of humans to fear snakes is derived from our evolutionary history. It is argued that findings from...     

The Seattle Longitudinal Study: Relationship Between Personality and Cognition

This article reviews the history, measures and principal findings of the Seattle Longitudinal Study. This study began in 1956 focusing upon age differences and age changes in cognitive abilities. Its sampling frame is a large HMO in the Pacific Northwest. The study has been expanded to investigate various influences on cognitive aging including, cognitive styles, personality traits, life styles, and family environment. Current interest is also in the early detection of risk for dementia. In addition, this article reports original analyses of the relation of personality dimensions to cognitive abilities (both concurrent and longitudinal). While personality remains relatively stable over the adult life span, modest proportions of variance are shared between various personality traits and the cognitive abilities.     

Speech and Language Disorders in Kenyan Children: Adapting Tools for Regions with Few Assessment Resources

This study sought to adapt a battery of Western speech and language assessment tools to a rural Kenyan setting. The tool was developed for children whose first language was KiGiryama, a Bantu language. A total of 539 Kenyan children (males=271, females=268, ethnicity=100% Kigiryama) were recruited. Data were initially collected from 52 children (pilot assessments), and then from a larger group of 487 children (152 cerebral malaria, 156 severe malaria and seizures, 179 unexposed). The language assessments were based upon the Content, Form and Use (C/F/U) model. The assessment was based upon the adapted versions of the Peabody Picture Vocabulary Test, Test for the Reception of Grammar, Renfrew Action Picture Test, Pragmatics Profile of Everyday Communication Skills in Children, Test of Word Finding and language specific tests of lexical semantics, higher level language. Preliminary measures of construct validity suggested that the theoretical assumptions behind the construction of the assessments were appropriate and re-test and inter-rater reliability scores were acceptable. These findings illustrate the potential to adapt Western speech and language assessments in other languages and settings, particularly those in which there is a paucity of standardised tools.     

Mental time travel for self and other in three- and four-year-old children

Humans possess the unique ability to mentally travel backward in time to re-experience past events (i.e., episodic memory) and forward in time to pre-experience future events (i.e., episodic foresight). Although originally viewed as different cognitive skills, they are now both viewed as components of the episodic memory system. Recently, it has been suggested that the episodic system may allow us to not only pre-experience and predict our own future but also that of another person. In the current study, we investigate this possibility by examining the ability of three- and four-year-old children to plan for their own future and for that of another person. We found that both three- and four-year-old children performed equally, when planning for their own future or when planning for the experimenter's future. These data are consistent with the finding that planning for someone else's future recruits the same neural structures that are used when planning for one's own future.     

The Suffocation of Marriage: Climbing Mount Maslow Without Enough Oxygen

This article distills insights from historical, sociological, and psychological perspectives on marriage to develop the suffocation model of marriage in America. According to this model, contemporary Americans are asking their marriage to help them fulfill different sets of goals than in the past. Whereas they ask their marriage to help them fulfill their physiological and safety needs much less than in the past, they ask it to help them fulfill their esteem and self-actualization needs much more than in the past. Asking the marriage to help them fulfill the latter, higher level needs typically requires sufficient investment of time and psychological resources to ensure that the two spouses develop a deep bond and profound insight into each other's essential qualities. Although some spouses are investing sufficient resources—and reaping the marital and psychological benefits of doing so—most are not. Indeed, they are, on average, investing less than in the past. As a result, mean levels of marital quality and personal well-being are declining over time. According to the suffocation model, spouses who are struggling with an imbalance between what they are asking from their marriage and what they are investing in it have several promising options for corrective action: intervening to optimize their available resources, increasing their investment of resources in the marriage, and asking less of the marriage in terms of facilitating the fulfillment of spouses’ higher needs. Discussion explores the implications of the suffocation model for understanding dating and courtship, sociodemographic variation, and marriage beyond American's borders.     

“Leaving it to God” Religion and Spirituality among Filipina Immigrant Breast Cancer Survivors

Many Filipinos have a powerful adherence to Catholicism. However, little is known about spirituality and religious involvement of Filipina Americans who have been diagnosed with breast cancer. Ten (n = 10) in-depth qualitative interviews with Filipina immigrant breast cancer survivors identified prayer to be the most common religious practice, followed by prayers by others and spiritual support from the Catholic Church. These findings can help clinicians and researchers understand the role of spirituality and religion in providing comfort and support for Filipina immigrant breast cancer patient as they face the stress of diagnosis and treatment.