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The normal aging process is generally associated with declines in working memory capacity that can affect global cognitive functioning and subsequently independent living abilities in older adults. However, great individual variability exists among the typical “healthy older adults” samples recruited by cognitive aging studies. Among the many individual difference factors that have been identified and studied, cardiovascular health has received increasing attention in recent years. The current study examined how hypertension medication status (i.e., taking vs not taking medications to maintain blood pressure) differentially affected the contributions of cardiovascular health factors on WMC, as well as the WMC-global cognitive functioning relationship in older adults.

Time-based prospective memory (TBPM) is the ability to perform an intended action at a precise moment in the future, such as to go to the office at 9 a.m. for a meeting. In older adults’ everyday life, TBPM is very relevant as health-related intentions are often part of daily activities, such as taking medication regularly or going to appointments with the doctor; yet, it is unclear how TBPM is affected by aging. In fact, the empirical evidence suggested that, although there are age-related differences in the TBPM paradigm among studies that measured TBPM using laboratory tasks, it is still unclear how large the age effect is. Furthermore, it is still unclear which kind of task-related factors can potentially moderate the magnitude of the age-related differences in TBPM, such as duration of the PM target time, frequency of the TBPM tasks, and the interval chosen to compute PM accuracy. Thus, the aims of the present meta-analysis will be (1) to quantify age-related differences in TBPM among studies that measured TBPM (accuracy and time monitoring) using laboratory tasks, and (2) to measure whether and how specific task-related factors (duration and frequency of the PM target time, and interval chosen for correct PM responses), can affect age-related differences in TBPM.

Time-based prospective memory (TBPM) is the ability to perform an intended action at a precise moment in the future, such as to go to the office at 9 a.m. for a meeting. In older adults’ everyday life, TBPM is very relevant as health-related intentions are often part of daily activities, such as taking medication regularly or going to appointments with the doctor; yet, it is unclear how TBPM is affected by aging. In fact, the empirical evidence suggested that, although there are age-related differences in the TBPM paradigm among studies that measured TBPM using laboratory tasks, it is still unclear how large the age effect is. Furthermore, it is still unclear which kind of task-related factors can potentially moderate the magnitude of the age-related differences in TBPM, such as duration of the PM target time, frequency of the TBPM tasks, and the interval chosen to compute PM accuracy. Thus, the aims of the present meta-analysis will be (1) to quantify age-related differences in TBPM among studies that measured TBPM (accuracy and time monitoring) using laboratory tasks, and (2) to measure whether and how specific task-related factors (duration and frequency of the PM target time, and interval chosen for correct PM responses), can affect age-related differences in TBPM.

We will investigate (1) how individual differences in empathy be associated with memory on details about the COVID-19 pandemic (i.e., whether the motivation to empathize and care about others facilitates one's tendency to memorize more accurately encode/retrieve details about the pandemic), (2) whether cognitive empathy and affective empathy are differently associated with memory, and (3) how does aging impact relationships between empathy and memory.

This article is from Frontiers in Aging Neuroscience , volume 6 . Abstract The LOU/C/Jall (LOU) rat strain is considered a model of healthy aging due to its increased longevity, maintenance of stable body weight (BW) throughout life and low incidence of age-related diseases. However, aging LOU rat cognitive and anxiety status has yet to be investigated. In the present study, male and female LOU rat cognitive performances (6–42 months) were assessed using novel object recognition and Morris Water Maze tasks. Recognition memory remained intact in all LOU rats up to 42 months of age. As for spatial memory, old LOU rat performed similarly as young animals for learning acquisition, reversal learning, and retention. While LOU rat BW remained stable despite aging, 20-month-old ad-libitum-fed (OAL) male Sprague Dawley rats become obese. We determined if long-term caloric restriction (LTCR) prevents age-related BW increase and cognitive deficits in this rat strain, as observed in the obesity-resistant LOU rats. Compared to young animals, recognition memory was impaired in OAL but intact in 20-month-old calorie-restricted (OCR) rats. Similarly, OAL spatial learning acquisition was impaired but LTCR prevented the deficits. Exacerbated stress responses may favor age-related cognitive decline. In the elevated plus maze and open field tasks, LOU and OCR rats exhibited high levels of exploratory activity whereas OAL rats displayed anxious behaviors. Expression of prodynorphin (Pdyn), an endogenous peptide involved in stress-related memory impairments, was increased in the hippocampus of OAL rats. Group 1 metabotropic glutamate receptor 5 and immediate early genes Homer 1a and Arc expression, both associated with successful cognitive aging, were unaltered in aging LOU rats but lower in OAL than OCR rats. Altogether, our results, supported by principal component analysis and correlation matrix, suggest that intact memory and low anxiety are associated with glutamatergic signaling and low Pdyn expression in the hippocampus of non-obese aging rats.

Metacognition is the ability to be aware, to think, and to control our own thoughts (Martinez, 2006). In that way, metamemory is a part of metacognition and refers to the ability to think about memory content and memory processes, as well as to the ability to control our memory system (Nelson & Narens, 1990). Metamemory could be assessed using different paradigms and indexes. In this study, we will focus on two measures of confidence judgments: the feeling of knowing (FOK) and the retrospective confidence judgments (RCJ). The FOK is assessed by prospective judgments made before a task. Participants must evaluate if they could recognize the correct response between several propositions in a next recognition phase. The RCJs are retrospective judgments made after a task. Participants have to evaluate their confidence about a response they gave. Previous studies using the FOK paradigm in healthy aging showed a dissociation between episodic FOK and semantic FOK (Devaluez et al., 2022). Older adults seem to be less accurate in episodic tasks whereas they are as accurate as younger adults in semantic tasks. Two hypotheses explain this dissociation between episodic FOK and semantic FOK in aging: the inferential-deficit hypothesis and the memory-constraint hypothesis. On one hand, the inferential-deficit hypothesis is based on Koriat’s theory (1993) and argues that the FOK deficit comes from a decrease in executive functioning. Considering that executive functioning is sustained by frontal areas, this hypothesis is coherent with the frontal decline observed in aging (Souchay et al., 2000). On the other hand, the memory-constrain hypothesis argues that the FOK deficit comes from encoding difficulties (Hertzog et al., 2010). Indeed, the FOK processes seem to be linked with memory processes and the same dissociation between semantic and episodic material is observed in memory (Koriat, 1993; Souchay et al., 2007). Episodic memory is impaired in aging whereas semantic memory is preserved. However, these previous studies used a different material between the episodic task and the semantic task (e.g., words for episodic task and definitions for semantic task). The effect of age on episodic FOK accuracy could be due to the stimuli used. To test this hypothesis, Morson and colleagues (2015) developed a paradigm using the same material between the semantic task and the episodic tasks (i.e., episodic stimuli were the targets from the semantic task). Results did not show any age effect on memory performance in both episodic and semantic tasks, but an age effect on episodic FOK was observed. It means that the episodic FOK deficit was still observed even if there was no encoding deficit. Authors suggested that episodic FOK deficit could come from recollection difficulties. Indeed, older adults have difficulties to use inferential cues to recollect memories (Bastin & Van der Linden, 2005). Moreover, older adults are less accurate for prospective judgements than for retrospective judgments than younger adults (Cauvin et al., 2019). Considering that prospective judgments require recollecting information from the encoding phase, this result is consistent with the recollection deficit hypothesis described by Morson and colleagues (2015). This dissociation in metamemory performance between episodic task and semantic task is not found using retrospective confidence judgments (RCJ). A task using both RCJ and FOK showed that metamemory efficiency on an episodic task was correlated with metamemory efficiency on a semantic task using RCJ, but this correlation was not found using FOK judgments (Mazancieux et al., 2020). Indeed, prospective and retrospective judgments are not based on the same cues. The RCJ are based on the effortlessness of the response, of the strength of the memory trace, on general knowledge about memory, and knowledge of how one’s memory works (Chua et al., 2009; Mazancieux, et al., 2020). However, the FOK judgments are based on inferential processes such as recollection of encoding context, partial information of the target, familiarity of the cue, and affective qualities of the target (Chua et al., 2009; Mazancieux, et al., 2020). The difference between prospective and retrospective judgments in a memory task increases with aging. Older adults are less accurate for prospective judgements than for retrospective judgments than younger adults (Cauvin et al., 2019). Considering that prospective judgments require recollecting information from the encoding phase, this result is consistent with the recollection deficit hypothesis described above. We will use a paradigm akin to the one used in Mazancieux et al. (2020). This experiment evaluates metamemory during episodic task and semantic task using both FOK and RCJ. We will compare metamemory efficiency for episodic memory and semantic memory using a large sample size (N = 100 per age group) composed of participants aged 20 to 40 and 60 to 80 years old.

Contains data and analysis for Greene, N.R., & Naveh-Benjamin, M. A specificity principle of memory: Evidence from aging and associative memory.

Contains data and analysis for Greene, N.R., & Naveh-Benjamin, M. A specificity principle of memory: Evidence from aging and associative memory.

Contributors: Iris Wiegand, Jeremy Wolfe For comprehensive documentation of this experiment, see "Files" below.

Contributors: Iris Wiegand, Jeremy Wolfe For comprehensive documentation of this experiment, see "Files" below.

Contributors: Iris Wiegand, Jeremy Wolfe For comprehensive documentation of this experiment, see "Files" below.

As we age, episodic memory starts to decline (Cansino, 2009; Nyberg & Tulving, 1996). This is associated with changes to resting state functional connectivity (RSFC) between cortical and subcortical networks, with healthy older adults experiencing increased functional connectivity between memory performance and RSFC in these regions compared to younger and middle age individuals (Fjell et al., 2015). Episodic memory declines notably following a traumatic brain injury (Wammes et al., 2017; Wright et al., 2010; Himanen et al., 2006). However, some work finds that while there is a lack of behavioral differences in episodic memory performance between HC and TBI participants, the neural signatures differ such that TBI individuals exhibit increased and distributed activation compared to their HC counterparts (Russell et al., 2011). Prior work has examined age-related and injury-related changes in functional connectivity with a cortical focus (Fjell et al., 2015; Palacios et al., 2012; Xiao et al., 2015). This has been seen within common networks such as the cingulo-opercular network (CON), default mode network (DNM), frontoparietal network (FPN; Palacios et al., 2012; Fjell et al., 2015; Hillary et al., 2012; Hausman et al., 2020). Additionally, while TBI work has examined working memory with respect to RSFC, episodic memory has not been examined in comparison to healthy counterparts to our knowledge (Palacios et al., 2012; Kasahara et al., 2011). However, episodic memory decline is often associated with subcortical regions, namely the hippocampus (Gorbach et al., 2015; Nyberg, 2017). The current set of analyses are interested in investigating episodic memory discrimination and the associated resting state functional connectivity (RSFC) changes between healthy and TBI older adults in subcortical structures. Further, the proposed analyses are also interested in the replicability of this RSFC across multiple subcortical parcellations (Brainnetome and Cole-Anticevic Brain-wide network partitions).

This is a pre-registration of Experiments 4-5 of this project.

Perma.cc archive of https://www.nia.nih.gov/health/memory-forgetfulness-and-aging-whats-normal-and-whats-not created on 2022-02-17 15:40:49.848416+00:00.

Perma.cc archive of https://www.nia.nih.gov/health/memory-forgetfulness-and-aging-whats-normal-and-whats-not created on 2022-02-17 15:40:49.848416+00:00.

In this paper, we review several important features of the out-of-equilibrium dynamics of spin glasses. Starting with the simplest experiments, we discuss the scaling laws used to describe the isothermal aging observed in spin glasses after a quench down to the low temperature phase. We report in particular new results on the sub-aging behaviour of spin glasses. We then discuss the rejuvenation and memory effects observed when a spin glass is submitted to temperature variations during aging, from the point of view of both energy landscape pictures and of real space pictures. We highlight the fact that both approaches point out the necessity of hierarchical processes involved in aging. Finally, we report an investigation of the effect of small temperature variations on aging in spin glass samples with various anisotropies which indicates that this hierarchy depends on the spin anisotropy.

In this paper, we review several important features of the out-of-equilibrium dynamics of spin glasses. Starting with the simplest experiments, we discuss the scaling laws used to describe the isothermal aging observed in spin glasses after a quench down to the low temperature phase. We report in particular new results on the sub-aging behaviour of spin glasses. We then discuss the rejuvenation and memory effects observed when a spin glass is submitted to temperature variations during aging, from the point of view of both energy landscape pictures and of real space pictures. We highlight the fact that both approaches point out the necessity of hierarchical processes involved in aging. Finally, we report an investigation of the effect of small temperature variations on aging in spin glass samples with various anisotropies which indicates that this hierarchy depends on the spin anisotropy.

In this paper, we review several important features of the out-of-equilibrium dynamics of spin glasses. Starting with the simplest experiments, we discuss the scaling laws used to describe the isothermal aging observed in spin glasses after a quench down to the low temperature phase. We report in particular new results on the sub-aging behaviour of spin glasses. We then discuss the rejuvenation and memory effects observed when a spin glass is submitted to temperature variations during aging, from the point of view of both energy landscape pictures and of real space pictures. We highlight the fact that both approaches point out the necessity of hierarchical processes involved in aging. Finally, we report an investigation of the effect of small temperature variations on aging in spin glass samples with various anisotropies which indicates that this hierarchy depends on the spin anisotropy.

In this paper, we review several important features of the out-of-equilibrium dynamics of spin glasses. Starting with the simplest experiments, we discuss the scaling laws used to describe the isothermal aging observed in spin glasses after a quench down to the low temperature phase. We report in particular new results on the sub-aging behaviour of spin glasses. We then discuss the rejuvenation and memory effects observed when a spin glass is submitted to temperature variations during aging, from the point of view of both energy landscape pictures and of real space pictures. We highlight the fact that both approaches point out the necessity of hierarchical processes involved in aging. Finally, we report an investigation of the effect of small temperature variations on aging in spin glass samples with various anisotropies which indicates that this hierarchy depends on the spin anisotropy.

Memory for visual objects has been shown to be much better than memory for auditory objects, and prior research in our lab has shown that divided attention affects memory for visual objects more so than auditory objects. Given that dividing attention and age often have similar behavioral effects on memory, we are investigating whether auditory memory will decline at a slower rate with age than visual memory. Participants aged 18 – 80 will take two memory tests, one over auditory objects (e.g., a dog bark) and another over visual objects (e.g., a balloon). After the memory tests, they will complete an anti-saccade task that assesses attentional control.

Memory for visual objects has been shown to be much better than memory for auditory objects, and prior research in our lab has shown that divided attention affects memory for visual objects more so than auditory objects. Given that dividing attention and age often have similar behavioral effects on memory, we are investigating whether auditory memory will decline at a slower rate with age than visual memory. Participants aged 18 – 80 will take two memory tests, one over auditory objects (e.g., a dog bark) and another over visual objects (e.g., a balloon). After the memory tests, they will complete an anti-saccade task that assesses attentional control.

Memory for visual objects has been shown to be much better than memory for auditory objects, and prior research in our lab has shown that divided attention affects memory for visual objects more so than auditory objects. Given that dividing attention and age often have similar behavioral effects on memory, we are investigating whether auditory memory will decline at a slower rate with age than visual memory. Participants aged 18 – 80 will take two memory tests, one over auditory objects (e.g., a dog bark) and another over visual objects (e.g., a balloon). After the memory tests, they will complete an anti-saccade task that assesses attentional control.

Memory for visual objects has been shown to be much better than memory for auditory objects, and prior research in our lab has shown that divided attention affects memory for visual objects more so than auditory objects. Given that dividing attention and age often have similar behavioral effects on memory, we are investigating whether auditory memory will decline at a slower rate with age than visual memory. Participants aged 18 – 80 will take two memory tests, one over auditory objects (e.g., a dog bark) and another over visual objects (e.g., a balloon). After the memory tests, they will complete an anti-saccade task that assesses attentional control.

Memory for visual objects has been shown to be much better than memory for auditory objects, and prior research in our lab has shown that divided attention affects memory for visual objects more so than auditory objects. Given that dividing attention and age often have similar behavioral effects on memory, we are investigating whether auditory memory will decline at a slower rate with age than visual memory. Participants aged 18 – 80 will take two memory tests, one over auditory objects (e.g., a dog bark) and another over visual objects (e.g., a balloon). After the memory tests, they will complete an anti-saccade task that assesses attentional control.

We have studied the effect of ageing within the miscibility gap on the electric, magnetic and thermodynamic properties of a non-stoichiometric Heusler Cu-Al-Mn shape-memory alloy, which undergoes a martensitic transition from a $bcc$-based ($\beta$-phase) towards a close-packed structure ($M$-phase). Negative magnetoresistance which shows an almost linear dependence on the square of magnetization with different slopes in the $M$- and $\beta$-phases, was observed. This magnetoresistive effect has been associated with the existence of Mn-rich clusters with the Cu$_2$AlMn-structure. The effect of an applied magnetic field on the martensitic transition has also been studied. The entropy change between the $\beta$- and $M$-phases shows negligible dependence on the magnetic field but it decreases significantly with annealing time within the miscibility gap. Such a decrease is due to the increasing amount of Cu$_2$MnAl-rich domains that do not transform martensitically.

We have studied the effect of ageing within the miscibility gap on the electric, magnetic and thermodynamic properties of a non-stoichiometric Heusler Cu-Al-Mn shape-memory alloy, which undergoes a martensitic transition from a $bcc$-based ($\beta$-phase) towards a close-packed structure ($M$-phase). Negative magnetoresistance which shows an almost linear dependence on the square of magnetization with different slopes in the $M$- and $\beta$-phases, was observed. This magnetoresistive effect has been associated with the existence of Mn-rich clusters with the Cu$_2$AlMn-structure. The effect of an applied magnetic field on the martensitic transition has also been studied. The entropy change between the $\beta$- and $M$-phases shows negligible dependence on the magnetic field but it decreases significantly with annealing time within the miscibility gap. Such a decrease is due to the increasing amount of Cu$_2$MnAl-rich domains that do not transform martensitically.

We have studied the effect of ageing within the miscibility gap on the electric, magnetic and thermodynamic properties of a non-stoichiometric Heusler Cu-Al-Mn shape-memory alloy, which undergoes a martensitic transition from a $bcc$-based ($\beta$-phase) towards a close-packed structure ($M$-phase). Negative magnetoresistance which shows an almost linear dependence on the square of magnetization with different slopes in the $M$- and $\beta$-phases, was observed. This magnetoresistive effect has been associated with the existence of Mn-rich clusters with the Cu$_2$AlMn-structure. The effect of an applied magnetic field on the martensitic transition has also been studied. The entropy change between the $\beta$- and $M$-phases shows negligible dependence on the magnetic field but it decreases significantly with annealing time within the miscibility gap. Such a decrease is due to the increasing amount of Cu$_2$MnAl-rich domains that do not transform martensitically.

http://uf.catalog.fcla.edu/uf.jsp?st=UF025784781&ix=nu&I=0&V=D&pm=1

We observe non-monotonic aging and memory effects, two hallmarks of glassy dynamics, in two disordered mechanical systems: crumpled thin sheets and elastic foams. Under fixed compression, both systems exhibit monotonic non-exponential relaxation. However, when after a certain waiting time the compression is partially reduced, both systems exhibit a non-monotonic response: the normal force first increases over many minutes or even hours until reaching a peak value, and only then relaxation is resumed. The peak-time scales linearly with the waiting time, indicating that these systems retain long-lasting memory of previous conditions. Our results and the measured scaling relations are in good agreement with a theoretical model recently used to describe observations of monotonic aging in several glassy systems, suggesting that the non-monotonic behavior may be generic and that a-thermal systems can show genuine glassy behavior.

Non-equilibrium aging dynamics in 3D Ising spin glass Cu$_{0.5}$Co$_{0.5}$Cl$_{2}$-FeCl$_{3}$ GBIC has been studied by zero-field cooled (ZFC) magnetization and low frequency AC magnetic susceptibility ($f = 0.05$ Hz), where $T_{g} = 3.92 \pm 0.11$ K. The time dependence of the relaxation rate $S(t) = (1/H)$d$M_{ZFC}/$d$\ln t$ for the ZFC magnetization after the ZFC aging protocol, shows a peak at a characteristic time $t_{cr}$ near a wait time $t_{w}$ (aging behavior), corresponding to a crossover from quasi equilibrium dynamics to non-equilibrium. The time $t_{cr}$ strongly depends on $t_{w}$, temperature ($T$), magnetic field ($H$), and the temperature shift ($\Delta T$). The rejuvenation effect is observed in both $\chi^{\prime}$ and $\chi^{\prime\prime}$ under the $T$-shift and $H$-shift procedures. The memory of the specific spin configurations imprinted during the ZFC aging protocol can be recalled when the system is re-heated at a constant heating rate. The aging, rejuvenation, and memory effects observed in the present system are discussed in terms of the scaling concepts derived from numerical studies on 3D Edwards-Anderson spin glass model.

There is mounting experimental evidence that strong off-equilibrium phenomena, such as ``memory'' or ``aging'' effects, play a crucial role in the physics of vortices in type II superconductors. We give a short review, based on a recently introduced schematic vortex model, of current progresses in understanding out of equilibrium vortex behaviours. We develop a unified description of ``memory'' phenomena in magnetic and transport properties, such as magnetisation loops and their ``anomalous'' 2nd peak, logarithmic creep, ``anomalous'' finite creep rate in the limit of vanishing temperature, ``memory'' and ``irreversibility'' in I-V characteristics, time dependent critical currents, ``rejuvenation'' and ``aging'' of the system response.

We have compared aging phenomena in the Fe_{0.5}Mn_{0.5}TiO_3 Ising spin glass and in the CdCr_{1.7}In_{0.3}S_4 Heisenberg-like spin glass by means of low-frequency ac susceptibility measurements. At constant temperature, aging obeys the same `$\omega t$ scaling' in both samples as in other systems. Investigating the effect of temperature variations, we find that the Ising sample exhibits rejuvenation and memory effects which are qualitatively similar to those found in other spin glasses, indicating that the existence of these phenomena does not depend on the dimensionality of the spins. However, systematic temperature cycling experiments on both samples show important quantitative differences. In the Ising sample, the contribution of aging at low temperature to aging at a slightly higher temperature is much larger than expected from thermal slowing down. This is at variance with the behaviour observed until now in other spin glasses, which show the opposite trend of a free-energy barrier growth as the temperature is decreased. We discuss these results in terms of a strongly renormalized microscopic attempt time for thermal activation, and estimate the corresponding values of the barrier exponent $\psi$ introduced in the scaling theories.

We have compared aging phenomena in the Fe_{0.5}Mn_{0.5}TiO_3 Ising spin glass and in the CdCr_{1.7}In_{0.3}S_4 Heisenberg-like spin glass by means of low-frequency ac susceptibility measurements. At constant temperature, aging obeys the same `$\omega t$ scaling' in both samples as in other systems. Investigating the effect of temperature variations, we find that the Ising sample exhibits rejuvenation and memory effects which are qualitatively similar to those found in other spin glasses, indicating that the existence of these phenomena does not depend on the dimensionality of the spins. However, systematic temperature cycling experiments on both samples show important quantitative differences. In the Ising sample, the contribution of aging at low temperature to aging at a slightly higher temperature is much larger than expected from thermal slowing down. This is at variance with the behaviour observed until now in other spin glasses, which show the opposite trend of a free-energy barrier growth as the temperature is decreased. We discuss these results in terms of a strongly renormalized microscopic attempt time for thermal activation, and estimate the corresponding values of the barrier exponent $\psi$ introduced in the scaling theories.

Curiosity is a form of intrinsic motivation, suggested to afford cognitive and neural engagement to explore and fill information gaps (Berlyne, 1978; Gruber, Valji, & Ranganath, 2019). While there is some evidence that curiosity decreases with age (Robinson, Demetre, & Litman, 2017), curiosity has also been suggested to act as cognitive enhancer to counteract cognitive deficits in older age (Sakaki, Yagi, & Murayama, 2018). In the present study, we aim to investigate the effects of state curiosity on recall of face-name associations in older age, and individual differences in the relationship between state curiosity and memory performance.

OLLI - Memory, Aging and Alzheimer's

This article is from Brain Sciences , volume 3 . Abstract This paper examines the intricate relationship between working memory (WM) capacity and inhibitory control as a function of both L2 proficiency and age. In both its design and research questions, this study closely follows Gass & Lee’s work, where both L1 and L2 Reading Span Tasks (as measures of WM capacity) and L1 and L2 Stroop interference tasks (to measure inhibitory control) were administered. In this study, the test battery is augmented by both an L1 and L2 C-test of overall language proficiency. Participants were 63 L1 Dutch speakers of L2 English, who had been immersed in an L2 environment for a considerable amount of time. Their data were set off against those of 54 monolingual Dutch speakers and 56 monolingual English speakers. At the time of testing, all the bilingual participants had a near-native command of English and their L1 and L2 WM scores were not found to be significantly different. However, discrepancies did occur in Stroop test scores of inhibition, where the bilinguals performed better in their L2 English than L1 Dutch. These main effects often contradicted the results found in Gass & Lee’s study, who examined less proficient L2 learners. An aging effect was furthermore found: older subjects consistently performed more poorly on WM and inhibition tasks than their younger peers. These results can shed light on how individual factors like WM capacity and inhibitory control interact in successful late bilinguals and how these dynamics shift with advanced age.

Includes bibliographical references (p. [321]-334)

Presented April 11, 2013

Presented April 11, 2013

450 pages ; 23 cm

This article is from Dialogues in Clinical Neuroscience , volume 2 . Abstract An increasing level of N-methyl-D-aspartate (NMDA) receptor hypofunction within the brain is associated with memory and learning impairments, with psychosis, and ultimately with excitotoxic brain injury. As the brain ages, the NMDA receptor system becomes progressively hypofunctional, contributing to decreases in memory and learning performance. In those individuals destined to develop Alzheimer's disease, other abnormalities (eg, amyloidopathy and oxidative stress) interact to increase the NMDA receptor hypofunction (NRHypo) burden. In these vulnerable individuals, the brain then enters into a severe and persistent NRHypo state, which can lead to widespread neurodegeneration with accompanying mental symptoms and further cognitive deterioration. If the hypotheses described herein prove correct, treatment implications may be considerable. Pharmacological methods for preventing the overstimulation of vulnerable corticolimbic pyramidal neurons developed in an animal model may be applicable to the prevention and treatment of Alzheimer's disease.

Many dense magnetic nanoparticle systems exhibit slow dynamics which is qualitatively indistinguishable from that observed in atomic spin glasses and its origin is attributed to dipole interactions among particle moments (or superspins). However, even in dilute nanoparticle systems where the dipole interactions are vanishingly small, slow dynamics is observed and is attributed solely to a broad distribution of relaxation times which in turn comes from that of the anisotropy energy barriers. To clarify characteristic differences between the two types of slow dynamics, we study a simple model of a non-interacting nanoparticle system (a superparamagnet) analytically as well as ferritin (a superparamagnet) and a dense Fe-N nanoparticle system (a superspin glass) experimentally. It is found that superparamagnets in fact show aging (a waiting time dependence) of the thermoremanent-magnetization as well as various memory effects. We also find some dynamical phenomena peculiar only to superspin glasses such as the flatness of the field-cooled magnetization below the critical temperature and memory effects in the zero-field-cooled magnetization. These dynamical phenomena are qualitatively reproduced by the random energy model, and are well interpreted by the so-called droplet theory in the field of the spin-glass study.

Aging dynamics in thin films of poly(methyl methacrylate) (PMMA) have been investigated through dielectric measurements for different types of aging processes. The dielectric constant was found to decrease with increasing aging time at an aging temperature in many cases. An increase in the dielectric constant was also observed in the long time region ($\ge$11h) near the glass transition temperature for thin films with thickness less than 26nm. In the constant rate mode including a temporary stop at a temperature $T_a$, the memory of the aging at $T_a$ was found to be kept and then to be recalled during the subsequent heating process. In the negative temperature cycling process, a strong rejuvenation effect has been observed after the temperature shift from the initial temperature $T_1$ to the second temperature $T_2$($=T_1+\Delta T$) when $\Delta T\approx -20$K. Furthermore, a full memory effect has also been observed for the temperature shift from $T_2$ to $T_1$. This suggests that the aging at $T_1$ is totally independent of that at $T_2$ for $\Delta T\approx -20$K. As $|\Delta T|$ decreases, the independence of the aging between the two temperatures was found to be weaken, $i.e.,$ the effective time, which is a measure of the contribution of the aging at $T_1$ to that at $T_2$, is a decreasing function of $|\Delta T|$ in the negative region of $\Delta T$. As the film thickness decreases from 514nm to 26nm, the $|\Delta T|$ dependence of the effective time was found to become much stronger. The contribution of the aging at $T_2$ to that at $T_1$ disappears more rapidly with increasing $|\Delta T|$ in thin film geometry than in the bulk state.

The temperature ($T$)-shift protcol of aging in the 3 dimensional (3D) Edwards- Anderson (EA) spin-glass (SG) model is studied through the out-of-phase component of the ac susceptibility simulated by the Monte Carlo method. For processes with a small magnitude of the $T$-shift, $\Delta T$, the memory imprinted before the $T$-shift is preserved under the $T$-change and the SG short-range order continuously grows after the $T$-shift, which we call the cumulative memory scenario. For a negative $T$-shift process with a large $\Delta T$ the deviation from the cumulative memory scenario has been observed for the first time in the numerical simulation. We attribute the phenomenon to the `chaos effect' which, we argue, is qualitatively different from the so-called rejuvenation effect observed just after the $T$-shift.

The temperature ($T$)-shift protcol of aging in the 3 dimensional (3D) Edwards- Anderson (EA) spin-glass (SG) model is studied through the out-of-phase component of the ac susceptibility simulated by the Monte Carlo method. For processes with a small magnitude of the $T$-shift, $\Delta T$, the memory imprinted before the $T$-shift is preserved under the $T$-change and the SG short-range order continuously grows after the $T$-shift, which we call the cumulative memory scenario. For a negative $T$-shift process with a large $\Delta T$ the deviation from the cumulative memory scenario has been observed for the first time in the numerical simulation. We attribute the phenomenon to the `chaos effect' which, we argue, is qualitatively different from the so-called rejuvenation effect observed just after the $T$-shift.

The temperature ($T$)-shift protcol of aging in the 3 dimensional (3D) Edwards- Anderson (EA) spin-glass (SG) model is studied through the out-of-phase component of the ac susceptibility simulated by the Monte Carlo method. For processes with a small magnitude of the $T$-shift, $\Delta T$, the memory imprinted before the $T$-shift is preserved under the $T$-change and the SG short-range order continuously grows after the $T$-shift, which we call the cumulative memory scenario. For a negative $T$-shift process with a large $\Delta T$ the deviation from the cumulative memory scenario has been observed for the first time in the numerical simulation. We attribute the phenomenon to the `chaos effect' which, we argue, is qualitatively different from the so-called rejuvenation effect observed just after the $T$-shift.

The temperature ($T$)-shift protcol of aging in the 3 dimensional (3D) Edwards- Anderson (EA) spin-glass (SG) model is studied through the out-of-phase component of the ac susceptibility simulated by the Monte Carlo method. For processes with a small magnitude of the $T$-shift, $\Delta T$, the memory imprinted before the $T$-shift is preserved under the $T$-change and the SG short-range order continuously grows after the $T$-shift, which we call the cumulative memory scenario. For a negative $T$-shift process with a large $\Delta T$ the deviation from the cumulative memory scenario has been observed for the first time in the numerical simulation. We attribute the phenomenon to the `chaos effect' which, we argue, is qualitatively different from the so-called rejuvenation effect observed just after the $T$-shift.

Using a nonequilibrium Monte Carlo method suitable to nanomagnetism, we investigate representative systems of interacting sub-10nm grained nanomagnets with large uniaxial anisotropy. Various magnetization memory and aging effects are found in such systems. We explain these dynamical effects using the distributed relaxation times of the interacting nanomagnets due to their large anisotropy energies.

This article is from PLoS ONE , volume 9 . Abstract Lymphopenia-induced proliferation (LIP), a mechanism to maintain a constant number of T cells in circulation, occurs in both normal aging and autoimmune disease. The incidence of most autoimmune diseases increases with age, and premature CD4+ T cell aging has been reported in several autoimmune diseases. In this study, we tested the hypothesis that premature CD4+ T cell aging can cause autoimmune disease by examining whether premature CD4+ T cell aging exists and causes LIP in our mouse model. Non-obese diabetic (NOD) mice were used because, in addition to Treg defects, the LIP of T cells has been shown to plays a causative role in the development of insulin-dependent diabetes mellitus (IDDM) in these mice. We found that with advancing age, NOD mice exhibited an accelerated decrease in the number of CD4+ T cells due to the loss of naïve cells. This was accompanied by an increase in the percentage of memory cells, leading to a reduced naïve/memory ratio. In addition, both the percentage of CD28+ cells in CD4+ T cells and IL-2 production decreased, while the percentage of FAS+CD44+ increased, suggesting that NOD mice exhibit premature CD4+ T cell aging. This process preferentially contributed to LIP of memory cells. Therefore, our results suggest that premature CD4+ T cell aging underlies the development of IDDM in NOD mice. Given that CD28 and IL-2 play important roles in Treg function, the relationships between premature CD4+ T cell aging and lymphopenia as well as Treg defects in autoimmune-prone NOD mice are proposed.