Associations Between Air Pollution Exposure and Empirically Derived Profiles of Cognitive Performance in Older Women

Background: Elucidating associations between exposures to ambient air pollutants and profiles of cognitive performance may provide insight into neurotoxic effects on the aging brain. Objective: We examined associations between empirically derived profiles of cognitive performance and residential concentrations of particulate matter of aerodynamic diameter < 2.5 (PM2.5) and nitrogen dioxide (NO2) in older women. Method: Women (N = 2,142) from the Women’s Health Initiative Study of Cognitive Aging completed a neuropsychological assessment measuring attention, visuospatial, language, and episodic memory abilities. Average yearly concentrations of PM2.5 and NO2 were estimated at the participant’s addresses for the 3 years prior to the assessment. Latent profile structural equation models identified subgroups of women exhibiting similar profiles across tests. Multinomial regressions examined associations between exposures and latent profile classification, controlling for covariates. Result: Five latent profiles were identified: low performance across multiple domains (poor multi-domain; n = 282;13%), relatively poor verbal episodic memory (poor memory; n = 216; 10%), average performance across all domains (average multi-domain; n = 974; 45%), superior memory (n = 381; 18%), and superior attention (n = 332; 15%). Using women with average cognitive ability as the referent, higher PM2.5 (per interquartile range [IQR] = 3.64μg/m3) was associated with greater odds of being classified in the poor memory (OR = 1.29; 95% Confidence Interval [CI] = 1.10–1.52) or superior attention (OR = 1.30; 95% CI = 1.10–1.53) profiles. NO2 (per IQR = 9.86 ppb) was associated with higher odds of being classified in the poor memory (OR = 1.38; 95% CI = 1.17–1.63) and lower odds of being classified with superior memory (OR = 0.81; 95% CI = 0.67–0.97). Conclusion: Exposure to PM2.5 and NO2 are associated with patterns of cognitive performance characterized by worse verbal episodic memory relative to performance in other domains.

Primate Memory

Chimpanzees use tools, pass on learning to their young, and in some cases exhibit far superior memory, speed, and accuracy in performing cognitive tasks than do humans. In this essay, Tetsuro Matsuzawa recounts some of the most striking aspects of his work on primates, memory, and the evolution of the human mind.

Paucity of Entorhinal Cortex Pathology of the Alzheimer’s Type in SuperAgers with Superior Memory Performance

Advancing age is typically associated with declining memory capacity and increased risk of Alzheimer’s disease (AD). Markers of AD such as amyloid plaques (AP) and neurofibrillary tangles (NFTs) are commonly found in the brains of cognitively average elderly but in more limited distribution than in those at the mild cognitive impairment and dementia stages of AD. Cognitive SuperAgers are individuals over age 80 who show superior memory capacity, at a level consistent with individuals 20–30 years their junior. Using a stereological approach, the current study quantitated the presence of AD markers in the memory-associated entorhinal cortex (ERC) of seven SuperAgers compared with six age-matched cognitively average normal control individuals. Amyloid plaques and NFTs were visualized using Thioflavin-S histofluorescence, 6E10, and PHF-1 immunohistochemistry. Unbiased stereological analysis revealed significantly more NFTs in ERC in cognitively average normal controls compared with SuperAgers (P &lt; 0.05) by a difference of ~3-fold. There were no significant differences in plaque density. To highlight relative magnitude, cases with typical amnestic dementia of AD showed nearly 100 times more entorhinal NFTs than SuperAgers. The results suggest that resistance to age-related neurofibrillary degeneration in the ERC may be one factor contributing to preserved memory in SuperAgers.

How can I use it? The role of functional fixedness in the survival-processing paradigm

After imagining being stranded in the grasslands of a foreign land without any basic survival material and rating objects with respect to their relevance in this situation, participants show superior memory performance for these objects compared to a control scenario. A possible mechanism responsible for this memory advantage is the richness and distinctiveness with which information is encoded in the survival-scenario condition. When confronted with the unusual task of thinking about how an object can be used in a life-threatening context, participants will most likely consider both common and uncommon (i.e., novel) functions of this object. These ideas about potential functions may later serve as powerful retrieval cues that boost memory performance. We argue that objects differ in their potential to be used as novel, creative survival tools. Some objects may be low in functional fixedness, meaning that it is possible to use them in many different ways. Other objects, in contrast, may be high in functional fixedness, meaning that the possibilities to use them in non-standard ways is limited. We tested experimentally whether functional fixedness of objects moderates the strength of the survival-processing advantage compared to a moving control scenario. As predicted, we observed an interaction of the functional fixedness level with scenario type: The survival-processing memory advantage was more pronounced for objects low in functional fixedness compared to those high in functional fixedness. These results are in line with the richness-of-encoding explanation of the survival-processing advantage.

Oxide-Electrolyte Thickness Dependence Diode-Like Threshold Switching and High on/off Ratio Characteristics by Using Al2O3 Based CBRAM

Diode-like threshold switching and high on/off ratio characteristics by using an Al/Ag/Al2O3/TiN conductive bridge resistive random access memories (CBRAM) have been obtained. The 5 nm-thick Al2O3 device shows superior memory parameters such as low forming voltage and higher switching uniformity as compared to the 20 nm-thick switching layer, owing to higher electric field across the material. Capacitance-voltage (CV) characteristics are observed for the Ag/Al2O3/TiN devices, suggesting the unipolar/bipolar resistive switching phenomena. Negative capacitance (NC) at low frequency proves inductive behavior of the CBRAM devices due to Ag ion migration into the Al2O3 oxide-electrolyte. Thicker Al2O3 film shows diode-like threshold switching behavior with long consecutive 10,000 cycles. It has been found that a thinner Al2O3 device has a larger on/off ratio of >108 as compared to a thicker one. Program/erase (P/E) cycles, read endurance, and data retention of the thinner Al2O3 oxide-electrolyte shows superior phenomena than the thicker electrolyte. The switching mechanism is also explored.

Gender differences in superior-memory SuperAgers and associated factors in an Australian cohort

Background: Despite expectations of deterioration in memory function with age, some older adults demonstrate superior memory performance and have been defined as SuperAgers. Method: SuperAgers were identified in a population-based prospective cohort in Australia ( n = 1,679; 49.4% female; mean age = 70.6 ±1.5 years) as participants who, over a 12-year period, consistently scored at or above the median of participants 40 years younger on recall tasks. Chi-square and t tests and logistic regression models measured associations between risk factors and being a SuperAger. Results: The prevalence of SuperAgers was higher in women (8.6%) than men (5.3%). Education was associated with being a SuperAger for women (adjusted odds ratio [OR] =1.13, 95% confidence interval [CI] = [1.01, 1.26]) and men (adjusted OR = 1.22, 95% CI = [1.05, 1.40]). Other associated factors were investigative activities and alcohol consumption for women and social activities and depressive symptoms for men. Conclusion: Adults over 60 can sustain superior memory recall; however, associated factors may vary between genders.