Working memory and inhibitory control across the life span: Intrusion errors in the Reading Span Test

Good-enough processing, home language proficiency, cognitive skills, and task effects for Korean heritage speakers' sentence comprehension

The present study investigates how heritage speakers conduct good-enough processing at the interface of home-language proficiency, cognitive skills (inhibitory control; working memory), and task types (acceptability judgement; self-paced reading). For this purpose, we employ two word-order patterns (verb-final vs. verb-initial) of two clausal constructions in Korean-suffixal passive and morphological causative-which contrast pertaining to the mapping between thematic roles and case-marking and the interpretive procedures driven by verbal morphology. We find that, while Korean heritage speakers demonstrate the same kind of acceptability-rating behaviour as monolingual Korean speakers do, their reading-time patterns are notably modulated by construction-specific properties, cognitive skills, and proficiency. This suggests a heritage speaker's ability and willingness to conduct both parsing routes, induced by linguistic cues in a non-dominant language, which are proportional to the computational complexity involving these cues. Implications of this study are expected to advance our understanding of a learner's mind for underrepresented languages and populations in the field.

Unicorn, Hare, or Tortoise? Using Machine Learning to Predict Working Memory Training Performance

People differ considerably in the extent to which they benefit from working memory (WM) training. Although there is increasing research focusing on individual differences associated with WM training outcomes, we still lack an understanding of which specific individual differences, and in what combination, contribute to inter-individual variations in training trajectories. In the current study, 568 undergraduates completed one of several N-back intervention variants over the course of two weeks. Participants' training trajectories were clustered into three distinct training patterns (high performers, intermediate performers, and low performers). We applied machine-learning algorithms to train a binary tree model to predict individuals' training patterns relying on several individual difference variables that have been identified as relevant in previous literature. These individual difference variables included pre-existing cognitive abilities, personality characteristics, motivational factors, video game experience, health status, bilingualism, and socioeconomic status. We found that our classification model showed good predictive power in distinguishing between high performers and relatively lower performers. Furthermore, we found that openness and pre-existing WM capacity to be the two most important factors in distinguishing between high and low performers. However, among low performers, openness and video game background were the most significant predictors of their learning persistence. In conclusion, it is possible to predict individual training performance using participant characteristics before training, which could inform the development of personalized interventions.

Wechsler Intelligence Scale for Adults - Fourth Edition profiles of adults with autism spectrum disorder

AIM

In this study, we have compared 229 Wechsler Adults Intelligence Scale - Fourth Edition (WAIS-IV) cognitive profiles of different severity adults with autism spectrum disorder to verify the impact of several variables including sex, age, level of education and autism severity level in an Italian sample. Moreover, we wanted to find out the optimal cut points for the major intelligence quotients in order to discriminate autism severity levels.

METHODS

Participants were recruited from two National Health System Center in two different Italian regions and were assessed with gold-standard instruments as a part of their clinical evaluation. According to DSM-5, cognitive domains were also measured with multi-componential tests. We used the Italian adaptation of WAIS-IV. We checked our hypotheses using linear regression models and receiver operating characteristics (ROC) curves.

RESULTS

Our results showed that age and level of education have a strong impact on Verbal Comprehension (VCI) and Working Memory Indexes (WMI). Gender differences are relevant when considering the VCI and Processing Speed index (PSI) in which women obtained the best performance. These differences are still relevant when considering cut points of ROC because 69 resulted to be the optimal cut point for women, 65 for men.

CONCLUSIONS

Few conclusions can be assumed only examining Full Scale Intelligence Quotient (FSIQ) scores as it includes many different information about broader cognitive abilities. Looking deeper at main indexes and their subtests findings are consistent with previous research on the disorder (moderate correlations of FSIQ, Perceptual Reasoning index, WMI and PSI with the participants' age), while other results are unforeseen (no effect of sex found on FSIQ score) or novel (significant effect of education on VCI and WMI). Using an algorithm predicting optimal cut point for discriminating through autism severity levels can help clinicians to better label and quantify the required help a person may need, a test cannot replace diagnostic and clinical evaluation by experienced clinicians.

Working Memory Training and Cortical Arousal in Healthy Older Adults: A Resting-State EEG Pilot Study

The current pilot study aimed to test the gains of working memory (WM) training, both at the short- and long-term, at a behavioral level, and by examining the electrophysiological changes induced by training in resting-state EEG activity among older adults. The study group included 24 older adults (from 64 to 75 years old) who were randomly assigned to a training group (TG) or an active control group (ACG) in a double-blind, repeated-measures experimental design in which open eyes, resting-state EEG recording, followed by a WM task, i.e., the Categorization Working Memory Span (CWMS) task, were collected before and after training, as well as at a 6-month follow-up session. At the behavioral level, medium to large Cohen's d effect sizes was found for the TG in immediate and long-term gains in the WM criterion task, as compared with small gains for the ACG. Regarding intrusion errors committed in the CWMS, an index of inhibitory control representing a transfer effect, results showed that medium to large effect sizes for immediate and long-term gains emerged for the TG, as compared to small effect sizes for the ACG. Spontaneous high-beta/alpha ratio analyses in four regions of interest (ROIs) revealed no pre-training group differences. Significantly greater TG anterior rates, particularly in the left ROI, were found after training, with frontal oscillatory responses being correlated with better post-training CWMS performance in only the TG. The follow-up analysis showed similar results, with greater anterior left high-beta/alpha rates among TG participants. Follow-up frontal high-beta/alpha rates in the right ROI were correlated with lower CWMS follow-up intrusion errors in only the TG. The present findings are further evidence of the efficacy of WM training in enhancing the cognitive functioning of older adults and their frontal oscillatory activity. Overall, these results suggested that WM training also can be a promising approach toward fostering the so-called functional cortical plasticity in aging.

Failing to forget? Evidence for both impaired and preserved working memory control in older adults

Voluntary forgetting is accomplished via top-down control over memory contents. Age-related declines in cognitive control may compromise voluntary forgetting. Using a working-memory variant of a directed forgetting task, we examined age differences in forgetting efficacy by analyzing direct measures of memory accuracy and two indirect measures of retention: proactive interference and semantic distortions. The directed forgetting effect in long-term memory was virtually absent in older adults. Further, compared to young adults, older adults recognized fewer to-be-remembered and more to-be-forgotten items in working memory. However, indirect measures of forgetting efficacy suggest some spared ability to control working memory contents in older adults: Both young and older adult participants exhibited reduced proactive interference for to-be-forgotten words (Experiment 1) and reduced semantic errors to to-be-forgotten list associates (Experiment 2) in working memory. Indirect memory measures of forgetting efficacy can provide a fuller understanding of spared and impaired control processes in older adults.

Effect of one-session focused attention meditation on the working memory capacity of meditation novices: A functional near-infrared spectroscopy study

INTRODUCTION

Previous studies have revealed that one-session focused attention meditation (FAM) can improve top-down attention control, which is one of the factors of working memory capacity (WMC). In addition, FAM shares various neural substrates, including the dorsolateral prefrontal cortex (DLPFC), with WMC. Thus, we hypothesized that one-session FAM would improve WMC by activating the DLPFC evoked by the top-down attention control. In this study, we examined whether FAM modified WMC in individuals with little to no meditation experience.

METHODS

The participants were randomly assigned to either the FAM group (N = 13) or the control group (N = 17) who engaged in random thinking (i.e., mind-wandering). Before and after each 15-min intervention, the participants' WMC was measured according to the total number of correct answers in the Reading Span Test. During each intervention, functional near-infrared spectroscopy was employed to measure the blood flow in the participants' DLPFC and determine the top-down attention control effect.

RESULTS

In the FAM group, WMC increased, and the bilateral DLPFC was activated during the intervention. As for the control group, WMC decreased after the intervention, and the bilateral DLPFC was not activated during the intervention. A correlation was also found among all participants between the increase in WMC and the activation of the bilateral DLPFC.

CONCLUSION

The study findings suggest that top-down attention control during FAM can activate the bilateral DLPFC and increase WMC among meditation novices.

Cognitive and non-cognitive variables influencing age-related effect of mind wandering across the adult life span

This study aimed to assess the effects of aging on mind wandering (MW) using a sustained attention to response task (SART) with a low cognitive demand. All task-unrelated thoughts (TUTs) and the subcategory of stimulus-independent thoughts (SITUTs) were examined across the adult life span. The relationship between MW, cognitive variables (attention, inhibition, working memory), and non-cognitive variables (mindfulness, psychological well-being, and anxiety) was investigated. The sample included 210 healthy participants from 20 to 89 years old. The overall results showed few or no age-related changes in both TUTs and SITUTs. Path analyses revealed that the effect of age on both TUTs and SITUTs was only indirect and mediated by attentional resources, as well as by some aspects of psychological well-being (i.e., emotional competence), which had a direct effect, however. These findings raise doubts about any age-related differences between young and older adults’ MW. Changes in MW across the adult life span are thus discussed along with the method and tasks used to assess it and different variables affecting it.

Age Differences in the Subcomponents of Executive Functioning

OBJECTIVES

Across the life span, deficits in executive functioning (EF) are associated with poor behavioral control and failure to achieve goals. Though EF is often discussed as one broad construct, a prominent model of EF suggests that it is composed of three subdomains: inhibition, set shifting, and updating. These subdomains are seen in both younger (YA) and older adults (OA), with performance deficits across subdomains in OA. Therefore, our goal was to investigate whether subdomains of EF might be differentially affected by age, and how these differences may relate to broader global age differences in EF.

METHODS

To assess these age differences, we conducted a meta-analysis at multiple levels, including task level, subdomain level, and of global EF. Based on previous work, we hypothesized that there would be overall differences in EF in OA.

RESULTS

Using 1,268 effect sizes from 401 articles, we found overall differences in EF with age. Results suggested that differences in performance are not uniform, such that variability in age effects emerged at the task level, and updating was not as affected by age as other subdomains.

DISCUSSION

These findings advance our understanding of age differences in EF, and stand to inform early detection of EF decline.

The role of inhibitory control in the development of analogical reasoning: From general to specific

This study examined the role of inhibitory control in the development of analogical reasoning using inter-task priming paradigms. In Experiment 1, 25 seven-year-olds, 27 nine-year-olds, and 27 adults completed Stroop tasks, which activated general inhibitory control ability, before analogical reasoning tasks. Children and adults performed faster on analogical reasoning tasks when they were primed by Stroop tasks. This priming effect was found to be stronger in children than in adults. In Experiment 2, 25 seven-year-olds, 28 nine-year-olds, and 28 adults completed relative number matching tasks, a more task-relevant inhibitory control task, before analogical reasoning tasks. The children and adults performed faster on analogical reasoning tasks when primed by relative number matching tasks. The priming effect was greater in seven-year-olds than in nine-year-olds and was greater in nine-year-olds than in adults. Thus, inhibitory control, whether assessed with general or specific tasks, played a priming role in analogical reasoning.

Working Memory Training for Older Adults After Major Surgery: Benefits to Cognitive and Emotional Functioning

OBJECTIVES

Cognitive and mood changes can affect postoperative recovery in hospitalized older adults undergoing major surgical procedures, but few studies have considered postoperative cognitive interventions to sustain such patients' cognitive functioning and mood. The aim of this pilot study was to assess the efficacy of working memory training in improving cognitive functioning and mood, or emotional functioning, in older adults undergoing major surgery.

METHODS

Thirty-four older adults (from 64 to 75 years of age) hospitalized for partial or total arthroplasty of the knee were randomly assigned to either a trained group (N = 18) or an active control group (N = 16). The former received working memory training during the postoperative period, while the latter engaged in alternative activities. In addition to specific training gains in a working memory task similar to the one used in the training (criterion task), transfer effects to cognitive abilities (short- and long-term memory, and cognitive inhibition), and mood or emotional functioning (signs of depression or anxiety) were investigated.

RESULTS

Immediately after the training, results showed a main effect of group (in favor of the trained group) in the criterion task, in one of the short-term memory measures, and in cognitive inhibition. In addition, only the trained group showed a decrease in depression and anxiety scores.

CONCLUSION

The results of this pilot study suggest that cognitive training targeting working memory administered in the postoperative period after major surgery can sustain older adults' cognitive and emotional functioning, and especially their mood.

Cognitive response to fish oil, blueberry, and combined supplementation in older adults with subjective cognitive impairment

Given evidence that eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and anthocyanin-rich blueberries provide neurocognitive benefit, we investigated long-term supplementation in older adults with cognitive complaints. In a 24-week randomized, double-blind, placebo-controlled trial, elderly men and women received daily fish oil (FO) or blueberry (BB) or both. Diet records confirmed that participants reduced background consumption of EPA, DHA, and anthocyanins as prescribed. Erythrocyte EPA + DHA composition increased in the FO groups (p = 0.0001). Total urinary anthocyanins did not differ between the groups after supplementation but glycoside and native (food) forms increased only in the BB-supplemented groups. The FO (p = 0.03) and BB (p = 0.05) groups reported fewer cognitive symptoms, and the BB group showed improved memory discrimination (p = 0.04), indicating that supplementation improved cognition. Cognitive benefit in the BB group was associated with the presence of urinary anthocyanins reflecting recent BB intake but not with anthocyanin metabolites. However, combined FO + BB treatment was not associated with cognitive enhancement as expected.

Intra-Individual Variability from a Lifespan Perspective: A Comparison of Latency and Accuracy Measures

Within-task variability across trials (intra-individual variability (IIV)) has been mainly studied using latency measures but rarely with accuracy measures. The aim of the Geneva Variability Study was to examine IIV in both latency and accuracy measures of cognitive performance across the lifespan, administering the same tasks to children, younger adults, and older adults. Six processing speed tasks (Response Time (RT) tasks, 8 conditions) and two working memory tasks scored in terms of the number of correct responses (Working Memory (WM)—verbal and visuo-spatial, 6 conditions), as well as control tasks, were administered to over 500 individuals distributed across the three age periods. The main questions were whether age differences in IIV would vary throughout the lifespan according (i) to the type of measure used (RTs vs. accuracy); and (ii) to task complexity. The objective of this paper was to present the general experimental design and to provide an essentially descriptive picture of the results. For all experimental tasks, IIV was estimated using intra-individual standard deviation (iSDr), controlling for the individual level (mean) of performance and for potential practice effects. As concerns RTs, and in conformity with a majority of the literature, younger adults were less variable than both children and older adults, and the young children were often the most variable. In contrast, IIV in the WM accuracy scores pointed to different age trends—age effects were either not observed or, when found, they indicated that younger adults were the more variable group. Overall, the findings suggest that IIV provides complementary information to that based on a mean performance, and that the relation of IIV to cognitive development depends on the type of measure used.

Auditory and cognitive performance in elderly musicians and nonmusicians

Musicians represent a model for examining brain and behavioral plasticity in terms of cognitive and auditory profile, but few studies have investigated whether elderly musicians have better auditory and cognitive abilities than nonmusicians. The aim of the present study was to examine whether being a professional musician attenuates the normal age-related changes in hearing and cognition. Elderly musicians still active in their profession were compared with nonmusicians on auditory performance (absolute threshold, frequency intensity, duration and spectral shape discrimination, gap and sinusoidal amplitude-modulation detection), and on simple (short-term memory) and more complex and higher-order (working memory [WM] and visuospatial abilities) cognitive tasks. The sample consisted of adults at least 65 years of age. The results showed that older musicians had similar absolute thresholds but better supra-threshold discrimination abilities than nonmusicians in four of the six auditory tasks administered. They also had a better WM performance, and stronger visuospatial abilities than nonmusicians. No differences were found between the two groups' short-term memory. Frequency discrimination and gap detection for the auditory measures, and WM complex span tasks and one of the visuospatial tasks for the cognitive ones proved to be very good classifiers of the musicians. These findings suggest that life-long music training may be associated with enhanced auditory and cognitive performance, including complex cognitive skills, in advanced age. However, whether this music training represents a protective factor or not needs further investigation.

Working Memory Training for Healthy Older Adults: The Role of Individual Characteristics in Explaining Short- and Long-Term Gains

Objective: The aim of the present study was to explore whether individual characteristics such as age, education, vocabulary, and baseline performance in a working memory (WM) task-similar to the one used in the training (criterion task)-predict the short- and long-term specific gains and transfer effects of a verbal WM training for older adults. Method: Four studies that adopted the Borella et al. (2010) verbal WM training procedure were found eligible for our analysis as they included: healthy older adults who attended either the training sessions (WM training group), or alternative activities (active control group); the same measures for assessing specific gains (on the criterion WM task), and transfer effects (nearest on a visuo-spatial WM task, near on short-term memory tasks and far on a measure of fluid intelligence, a measure of processing speed and two inhibitory measures); and a follow-up session. Results: Linear mixed models confirmed the overall efficacy of the training, in the short-term at least, and some maintenance effects. In the trained group, the individual characteristics considered were found to contribute (albeit only modestly in some cases) to explaining the effects of the training. Conclusions: Overall, our findings suggest the importance of taking individual characteristics and individual differences into account when examining WM training gains in older adults.

Age differences in behavioral and neural correlates of proactive interference: Disentangling the role of overall working memory performance

Reliable performance in working memory (WM) critically depends on the ability to resist proactive interference (PI) from previously relevant WM contents. Both WM performance and PI susceptibility are subject to cognitive decline at older adult age. However, the behavioral and neural processes underlying these co-evolving developmental changes and their potential interdependencies are not yet understood. Here, we investigated PI using a recent-probes WM paradigm and functional MRI in a cross-sectional sample of younger (n=18, 10 female, 23.4 ± 2.7 years) and older adults (n=18, 10 female, 70.2 ± 2.7 years). As expected, older adults showed lower WM performance and higher PI susceptibility than younger adults. Resolution of PI activated a mainly bilateral frontal network across all participants. Significant interactions with age indicated reduced neural activation in older adults for PI resolution. A second analysis in a selection of younger and older adults (n=12 each) with matched WM performance also revealed significant differences in PI between both age groups and - on a descriptive level - again a hypo-activation of the older adults' PI network. But the differential effect of age on the neural PI effects did not reach significance in this smaller sample most likely to the reduced statistical power. However, given the highly similar patterns in both the overall and the WM-matched samples, we propose that the hypo-activation of the PI network in the older adults may not be attributable to age-related differences in overall WM performance, hence suggesting that higher PI susceptibility in older adult age does not directly depend on their lower WM performance.

Attentional flexibility and memory capacity in conductors and pianists

Individuals with high working memory (WM) capacity also tend to have better selective and divided attention. Although both capacities are essential for skilled performance in many areas, evidence for potential training and expertise effects is scarce. We investigated the attentional flexibility of musical conductors by comparing them to equivalently trained pianists. Conductors must focus their attention both on individual instruments and on larger sections of different instruments. We studied students and professionals in both domains to assess the contributions of age and training to these skills. Participants completed WM span tests for auditory and visual (notated) pitches and timing durations, as well as long-term memory tests. In three dichotic attention tasks, they were asked to detect small pitch and timing deviations from two melodic streams presented in baseline (separate streams), selective-attention (concentrating on only one stream), and divided-attention (concentrating on targets in both streams simultaneously) conditions. Conductors were better than pianists in detecting timing deviations in divided attention, and experts detected more targets than students. We found no group differences for WM capacity or for pitch deviations in the attention tasks, even after controlling for the older age of the experts. Musicians' WM spans across multimodal conditions were positively related to selective and divided attention. High-WM participants also had shorter reaction times in selective attention. Taken together, conductors showed higher attentional flexibility in successfully switching between different foci of attention.

Subcortical glutamate mediates the reduction of short-range functional connectivity with age in a developmental cohort

Marked changes in brain physiology and structure take place between childhood and adulthood, including changes in functional connectivity and changes in the balance between main excitatory and inhibitory neurotransmitters glutamate (Glu) and GABA. The balance of these neurotransmitters is thought to underlie neural activity in general and functional connectivity networks in particular, but so far no studies have investigated the relationship between human development related differences in these neurotransmitters and concomitant changes in functional connectivity. GABA+/H2O and Glu/H2O levels were acquired in a group of healthy children, adolescents, and adults in a subcortical (basal ganglia) region, as well as in a frontal region in adolescents and adults. Our results showed higher GABA+/Glu with age in both the subcortical and the frontal voxel, which were differentially associated with significantly lower Glu/H2O with age in the subcortical voxel and by significantly higher GABA+/H2O with age in the frontal voxel. Using a seed-to-voxel analysis, we were further able to show that functional connectivity between the putamen (seed) and other subcortical structures was lower with age. Lower subcortical Glu/H2O with age mediated the lower connectivity in the dorsal putamen. Based on these results, and the potential role of Glu in synaptic pruning, we suggest that lower Glu mediates a reduction of local connectivity during human development.

The effect of orthographic neighborhood in the reading span task

This study aimed at examining whether and to what extent orthographic neighborhood of words influences performance in a working memory span task. Twenty-five participants performed a reading span task in which final words to be memorized had either no higher frequency orthographic neighbor or at least one. In both neighborhood conditions, each participant completed three series of two, three, four, or five sentences. Results indicated an interaction between orthographic neighborhood and list length. In particular, an inhibitory effect of orthographic neighborhood on recall appeared in list length 5. A view is presented suggesting that words with higher frequency neighbors require more resources to be memorized than words with no such neighbors. The implications of the results are discussed with regard to memory processes and current models of visual word recognition.

Relationships between mind-wandering and attentional control abilities in young adults and adolescents

Recent findings suggest that mind-wandering-the occurrence of thoughts that are both stimulus-independent and task-unrelated-corresponds to temporary failures in attentional control processes involved in maintaining constant task-focused attention. Studies supporting this proposal are, however, limited by a possible confound between mind-wandering episodes and other kinds of conscious experiences, such as external distractions (i.e., interoceptive sensations and exteroceptive perceptions). In the present study, we addressed this issue by examining, in adolescents and young adults, the relations between tasks measuring attentional control abilities and a measure of mind-wandering that is distinct from external distractions. We observed (1) that adolescents experienced more frequent external distractions, but not more mind-wandering, than young adults during the Sustained Attention to Response Task (SART) and (2) that, in young adults, the influence of external distractions on SART performance was fully accounted for by attentional control abilities, whereas mind-wandering was associated with decreases in SART performance above and beyond what was explained by attentional control abilities. These results show that mind-wandering cannot be entirely reduced to failures in the ability to maintain one's attention focused on task, and suggest that external distractions rather than mind-wandering are due to attentional control failures.

Information processing and proactive interference in children with and without specific language impairment

PURPOSE

Increasing evidence suggests that children with specific language impairment (SLI) have a deficit in inhibition control, but research isolating specific abilities is scarce. The goal of this study was to examine whether children with SLI differ from their peers in resistance to proactive interference under different conditions.

METHOD

An information processing battery with manipulations in interference was administered to 66 children (SLI, age matched peers, and language-matched controls). In Experiment 1, previously relevant targets were used as distractors to create conflict. Experiment 2 used item repetitions to examine how practice strengthens word representations and how the strength of a response impacts performance on the following item.

RESULTS

Children with SLI performed similarly to their peers in the baseline condition but were more susceptible to proactive interference than the controls in both experimental conditions. Children with SLI demonstrated difficulty suppressing irrelevant information, made significantly more interference errors than their peers, and showed a slower rate of implicit learning.

CONCLUSION

Children with SLI show weaker resistance to proactive interference than their peers, and this deficit impacts their information processing abilities. The coordination of activation and inhibition is less efficient in these children, but future research is needed to further examine the interaction between these two processes.

When the mind wanders: age-related differences between young and older adults

Interest in mind wandering (MW) has grown in recent years, but few studies have assessed this phenomenon in older adults. The aim of this study was to assess age-related differences between young, young-old and old-old adults in MW using two versions of the sustained attention to response task (SART), one perceptual and one semantic. Different indicators were examined (i.e., reported MW episodes and behavioral indices of MW such as response time latency and variability, incorrect response and omission errors). The relationship between MW, certain basic mechanisms of cognition (working memory, inhibition and processing speed), cognitive failures and intrusive thoughts in everyday life was also explored. Findings in both versions of the SART indicated that older adults reported a lower frequency of MW episodes than young adults, but some of the behavioral indices of MW (response time variability, incorrect response and omission errors) were higher in old-old adults. This seems to suggest that MW becomes less frequent with aging, but more pervasive and detrimental to performance. Our results also indicated that the role of age and cognitive mechanisms in explaining MW depends on the demands of the SART task considered.

The decline of verbal and visuospatial working memory across the adult life span

It has been well established that working memory abilities decrease with advancing age; however, the specific time point in the adult life span at which this deficit begins and the rate at which it advances are still controversial. There is no agreement on whether working memory declines equally for visuospatial and verbal information, and the literature disagrees on how task difficulty may influence this decay. We addressed these questions in a lifespan sample of 1,500 participants between 21 and 80 years old. The n-back task was used, with letters and circles presented at different positions around an imaginary circle, to evaluate working memory in the verbal and visuospatial domains, respectively. The participants' task was to judge whether the current stimulus matched a stimulus that was shown n trials prior. Both domains were evaluated in two levels of difficulty: 1-back and 2-back. The comparison across decades showed that discrimination in the visuospatial and 1-back tasks started to decline earlier in women than in men; however, discrimination was equal between the sexes in the verbal and 2-back tasks. Performance on tasks in the visuospatial domain exhibited more pronounced decline than in those in the verbal domain. The rate of decline in working memory accuracy was superior in 2-back tasks than in 1-back tasks, independent of the domain. These results revealed that the effects of aging on working memory are less dependent on the type of information and more reliant on the resources demanded by the task.

The role of auditory abilities in basic mechanisms of cognition in older adults

The aim of this study was to assess age-related differences between young and older adults in auditory abilities and to investigate the relationship between auditory abilities and basic mechanisms of cognition in older adults. Although there is a certain consensus that the participant’s sensitivity to the absolute intensity of sounds (such as that measured via pure tone audiometry) explains his/her cognitive performance, there is not yet much evidence that the participant’s auditory ability (i.e., the whole supra-threshold processing of sounds) explains his/her cognitive performance. Twenty-eight young adults (age <35), 26 young–old adults (65 í age í 75), and 28 old–old adults (age >75) were presented with a set of tasks estimating several auditory abilities (i.e., frequency discrimination, intensity discrimination, duration discrimination, timbre discrimination, gap detection, amplitude modulation detection, and the absolute threshold for a 1 kHz pure tone) and the participant’s working memory, cognitive inhibition, and processing speed. Results showed an age-related decline in both auditory and cognitive performance. Moreover, regression analyses showed that a subset of the auditory abilities (i.e., the ability to discriminate frequency, duration, timbre, and the ability to detect amplitude modulation) explained a significant part of the variance observed in the processing speed of older adults. Overall, the present results highlight the relationship between auditory abilities and basic mechanisms of cognition.

Age-related differences in working memory: ERPs reveal age-related delays in selection- and inhibition-related processes

Faulty inhibition is implicated in age-related working memory decline. ERP signs of selection and inhibition of items in working memory (WM) are, respectively, a cue-locked parietal positivity (∼ 350 ms) and a probe-locked frontal negativity (∼ 520 ms). To determine when in the older age range differences in selective and inhibitory processes might occur, ERPs were recorded in a WM task from 20 young (20-28), 20 young-old (60-70), and 20 old-old (71-82) adults. A 4-digit display was followed by a cue indicating which 2 of 4 digits were relevant. Proactive interference (PI), the reaction time difference between a matching and non-matching to-be-ignored digit was larger, relative to the young, in both older groups. Compared to the young, both the cue- and probe-locked activities were prolonged in the older groups. Although there were no topographic differences among the age groups, the prolonged PI and associated ERPs suggest a relative age-related deficit in inhibition.

Remembering the past and imagining the future: age-related differences between young, young-old and old-old

BACKGROUND AND AIMS

Few studies have analyzed the ability to remember past events and imagine future events in older adults. The present study examines age-related differences between young, young-old, and old-old adults in creating mental images of autobiographic episodes from the past and from the future.

METHODS

Cue words were presented, and for each of these, participants had to remember an autobiographic past event or imagine a future event. Performance was analyzed in terms of type of autobiographical images created (specific or general) and their vividness. Moreover, individual differences in temporal perspective were analyzed as a mediator of performance.

RESULTS

Old-old adults produced less specific, but more general events compared to young adults and young-old in the future condition. Moreover, only old-old produced more general images in the future than in the past. In contrast, young-old showed intermediate performance, more similar to that of young adults for both specific and autobiographical images. A similar pattern was found with regard to vividness of images produced. Regression analyses showed that the proportion of images produced in the past and the future was interdependent and was accounted by age and individual differences in temporal perspective.

CONCLUSIONS

Taken together, these results indicate that the ability to recall specific autobiographical past events and imagined future events is maintained in young-old, but is impaired when old-old adults are considered. Results are discussed in terms of the more accentuated cognitive decline that occurs in late adulthood.

Inhibitory mechanisms in Down syndrome: is there a specific or general deficit?

The cognitive profile of individuals with Down syndrome (DS) is known to be characterized by an impaired executive functioning, but inhibition-related processes have not been extensively examined in this setting. The aim of the present study was to investigate whether individuals with DS have any specific or general deficit in inhibitory processes. Tasks measuring prepotent response inhibition (the animal Stroop test), proactive interference (proactive interference task and intrusion errors), and response to distracters (directed forgetting task) were administered together with a working memory test to 19 individuals with DS and 19 typically developing (TD) children matched for mental age. Confirming previous findings, our results showed that the DS group performed less well in a verbal working memory task than the TD children. Analyzing our findings for the three inhibitory tasks yielded a picture of the DS children having a generalized difficulty in suppressing information that is irrelevant, or no longer relevant, to the goals of the task. These results suggest that DS is related not to specific, but rather to generalized inhibitory difficulties.

Concord grape juice supplementation and neurocognitive function in human aging

Polyphenol compounds found in berry fruits, in particular flavonoids, have been associated with health benefits including improvement in cognition and neuronal function with aging. Concord grape juice contains polyphenols, including anthocyanins and flavanols, and previous research has shown improvement in a number of human health conditions with grape juice supplementation. In the current study, older adult subjects with mild cognitive impairment consumed Concord grape juice or placebo for 16 weeks and were administered assessments of memory function and brain activation pre- and postintervention. Participants who consumed grape juice showed reduced semantic interference on memory tasks. Relatively greater activation in anterior and posterior regions of the right hemisphere was also observed with functional magnetic resonance imaging in the grape juice treated subjects. These findings provide further evidence that Concord grape juice can enhance neurocognitive function in older adults with mild memory decline.

Similarity-Based Interference in a Working Memory Numerical Updating Task

Similarity among representations held simultaneously in working memory (WM) is a factor which increases interference and hinders performance. The aim of the current study was to investigate age-related differences between younger and older adults in a working memory numerical updating task, in which the similarity between information held in WM was manipulated. Results showed a higher susceptibility of older adults to similarity-based interference when accuracy, and not response times, was considered. It was concluded that older adults’ WM difficulties appear to be due to the availability of stored information, which, in turn, might be related to the ability to generate distinctive representations and to the process of binding such representations to their context when similar information has to be processed in WM.

Effect of Cognitive Load on Working Memory Forgetting in Aging

Functional approaches to working memory (WM) have been proposed recently to better investigate “maintenance” and “processing” mechanisms. The cognitive load (CL) hypothesis presented in the “Time-Based Resource-Sharing” model (Barrouillet & Camos, 2007) suggests that forgetting from WM (maintenance) can be investigated by varying the presentation rate and processing speed (processing). In this study, young and elderly participants were compared on WM tasks in which the difference in processing speed was controlled by CL manipulations. Two main results were found. First, when time constraints (CL) were matched for the two groups, no aging effect was observed. Second, whereas a large variation in CL affected WM performance, a small CL manipulation had no effect on the elderly. This suggests that WM forgetting cannot be completely accounted for by the CL hypothesis. Rather, it highlights the need to explore restoration times in particular, and the nature of the refreshment mechanisms within maintenance.

Attentional control constrains visual short-term memory: insights from developmental and individual differences

The mechanisms by which attentional control biases mnemonic representations have attracted much interest but remain poorly understood. As attention and memory develop gradually over childhood and variably across individuals, assessing how participants of different ages and ability attend to mnemonic contents can elucidate their interplay. In Experiment 1, 7-year-olds, 10-year-olds, and adults were asked to report whether a probe item had been part of a previously presented four-item array. The initial array could either be uncued, be preceded ("precued"), or followed ("retrocued") by a spatial cue orienting attention to one of the potential item locations. Performance across groups was significantly improved by both cue types, and individual differences in children's retrospective attentional control predicted their visual short-term and working memory span, whereas their basic ability to remember in the absence of cues did not. Experiment 2 imposed a variable delay between the array and the subsequent orienting cue. Cueing benefits were greater in adults than in 10-year-olds, but they persisted even when cues followed the array by nearly 3 seconds, suggesting that orienting operated on durable short-term representations for both age groups. The findings indicate that there are substantial developmental and individual differences in the ability to control attention to memory and that in turn these differences constrain visual short-term memory capacity.

Improved cognitive-cerebral function in older adults with chromium supplementation

Insulin resistance is implicated in the pathophysiological changes associated with Alzheimer's disease, and pharmaceutical treatments that overcome insulin resistance improve memory function in subjects with mild cognitive impairment (MCI) and early Alzheimer's disease. Chromium (Cr) supplementation improves glucose disposal in patients with insulin resistance and diabetes. We sought to assess whether supplementation with Cr might improve memory and neural function in older adults with cognitive decline. In a placebo-controlled, double-blind trial, we randomly assigned 26 older adults to receive either chromium picolinate (CrPic) or placebo for 12 weeks. Memory and depression were assessed prior to treatment initiation and during the final week of treatment. We also performed functional magnetic resonance imaging (fMRI) scans on a subset of subjects. Although learning rate and retention were not enhanced by CrPic supplementation, we observed reduced semantic interference on learning, recall, and recognition memory tasks. In addition, fMRI indicated comparatively increased activation for the CrPic subjects in right thalamic, right temporal, right posterior parietal, and bifrontal regions. These findings suggest that supplementation with CrPic can enhance cognitive inhibitory control and cerebral function in older adults at risk for neurodegeneration.