Use it or lose it? SES mitigates age-related decline in a recency/recognition task

Childhood engagement in cognitively stimulating activities moderates relationships between brain structure and cognitive function in adulthood

Greater engagement in cognitively stimulating activities (CSA) during adulthood has been shown to protect against neurocognitive decline, but no studies have investigated whether CSA during childhood protects against effects of brain changes on cognition later in life. The current study tested the moderating role of childhood CSA in the relationships between brain structure and cognitive performance during adulthood. At baseline (N=250) and 5-year follow-up (N=204) healthy adults aged 20-80 underwent MRI to assess four structural brain measures and completed neuropsychological tests to measure three cognitive domains. Participants were categorized into low and high childhood CSA based on self-report questionnaires. Results of multivariable linear regressions analyzing interactions between CSA, brain structure, and cognition showed that higher childhood CSA was associated with a weaker relationship between cortical thickness and memory at baseline, and attenuated the effects of change in cortical thickness and brain volume on decline in processing speed over time. These findings suggest higher CSA during childhood may mitigate the effects of brain structure changes on cognitive function later in life.

The Neurobiology of Life Course Socioeconomic Conditions and Associated Cognitive Performance in Middle to Late Adulthood

Despite major advances, our understanding of the neurobiology of life course socioeconomic conditions is still scarce. This study aimed to provide insight into the pathways linking socioeconomic exposures-household income, last known occupational position, and life course socioeconomic trajectories-with brain microstructure and cognitive performance in middle to late adulthood. We assessed socioeconomic conditions alongside quantitative relaxometry and diffusion-weighted magnetic resonance imaging indicators of brain tissue microstructure and cognitive performance in a sample of community-dwelling men and women (N = 751, aged 50-91 years). We adjusted the applied regression analyses and structural equation models for the linear and nonlinear effects of age, sex, education, cardiovascular risk factors, and the presence of depression, anxiety, and substance use disorders. Individuals from lower-income households showed signs of advanced brain white matter (WM) aging with greater mean diffusivity (MD), lower neurite density, lower myelination, and lower iron content. The association between household income and MD was mediated by neurite density (B = 0.084, p = 0.003) and myelination (B = 0.019, p = 0.009); MD partially mediated the association between household income and cognitive performance (B = 0.017, p < 0.05). Household income moderated the relation between WM microstructure and cognitive performance, such that greater MD, lower myelination, or lower neurite density was only associated with poorer cognitive performance among individuals from lower-income households. Individuals from higher-income households showed preserved cognitive performance even with greater MD, lower myelination, or lower neurite density. These findings provide novel mechanistic insights into the associations between socioeconomic conditions, brain anatomy, and cognitive performance in middle to late adulthood.

Order, please! Explicit sequence learning in hybrid search in younger and older age

Sequence learning effects in simple perceptual and motor tasks are largely unaffected by normal aging. However, less is known about sequence learning in more complex cognitive tasks that involve attention and memory processes and how this changes with age. In this study, we examined whether incidental and intentional sequence learning would facilitate hybrid visual and memory search in younger and older adults. Observers performed a hybrid search task, in which they memorized four or 16 target objects and searched for any of those target objects in displays with four or 16 objects. The memorized targets appeared either in a repeating sequential order or in random order. In the first experiment, observers were not told about the sequence before the experiment. Only a subset of younger adults and none of the older adults incidentally learned the sequence. The "learners" acquired explicit knowledge about the sequence and searched faster in the sequence compared to random condition. In the second experiment, observers were told about the sequence before the search task. Both younger and older adults searched faster in sequence blocks than random blocks. Older adults, however, showed this sequence-learning effect only in blocks with smaller target sets. Our findings indicate that explicit sequence knowledge can facilitate hybrid search, as it allows observers to predict the next target and restrict their visual and memory search. In older age, the sequence-learning effect is constrained by load, presumably due to age-related decline in executive functions.

Associations between life course marital biography and late-life memory decline

Late-life marital status is associated with cognitive aging; however, the influence of life course marital biography (i.e., changes in marital status) on late-life cognitive trajectories, as well as gender differences in the effects of marital biography, remain to be explored. Associations between (a) marital status at study baseline (currently married, previously married, never married) and (b) retrospectively reported life course marital biography (i.e., age at first marriage, time spent unmarried following initial marriage, history of divorce, history of widowhood) and up to 20 years of subsequent episodic memory trajectories were examined using latent growth curve models in 3,061 participants aged 51 + in the Health and Retirement Study 2017 Life History Mail Survey. Gender differences were examined with multiplicative interaction terms and stratified models. Participants who were married at study baseline demonstrated higher initial memory than previously and never married individuals. Older age at first marriage and shorter duration spent unmarried were each associated with better initial episodic memory among previously married individuals only; longer duration spent unmarried was associated with slower memory decline. Stratified models suggested that these associations may be driven by women. These results highlight the importance of considering multiple aspects of marital biography, not just current marital status, in cognitive aging research. Marital biography may have an enduring influence on cognitive aging, particularly among previously married older women. Future work is needed to identify mechanisms (e.g., socioeconomic resources, cognitive stimulation, self and spousal health, emotional support) through which marital histories influence cognitive aging. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

The Relationship Between Socioeconomic Status and Scalp Event-Related Potentials: A Systematic Review

Several decades of behavioral research have established that variations in socioeconomic status (SES) are related to differences in cognitive performance. Neuroimaging and psychophysiological techniques have recently emerged as a method of choice to better understand the neurobiological processes underlying this phenomenon. Here we present a systematic review of a particular sub-domain of this field. Specifically, we used the PICOS approach to review studies investigating potential relationships between SES and scalp event-related brain potentials (ERP). This review found evidence that SES is related to amplitude variations in a diverse range of ERPs: P1, N1, N2, Error-Related Negativities (ERN), N400, auditory evoked potentials, negative difference waves (Nd), P3 and slow waves (SW). These ERPs include early, mid-latency and late potentials that reflect a broad range of cognitive processes (e.g., automatic attentional processes, overt attention, language, executive function, etc.). In this review, all SES effects on ERPs appeared to reflect an impairment or a less efficient form of task-related neural activity for low-SES compared to high-SES individuals. Overall, these results confirm that a wide variety of distinct neural processes with different functional meanings are sensitive to SES differences. The findings of this review also suggest that the relationship between SES and some ERP components may depend on the developmental stage of study participants. Results are further discussed in terms of the current limitations of this field and future avenues of research.

Neural correlates of episodic memory change in increasing age: a longitudinal event-related potential study

Using a longitudinal design, we examined whether event-related brain potentials (ERPs) correlates of successful episodic memory retrieval varied over a 4-year period according to the level of memory change. ERPs were recorded while participants performed a word-stem cued-recall task, and this procedure was repeated 4 years later. We compared the ERP old/new effect patterns of participants whose memory performance remained stable over time (stable group) with those of participants experiencing episodic memory decline (decline group). The pattern of change of the old/new effect differed between groups. At T1, the two groups exhibited the same pattern, with a positive frontal and parietal old/new effect. For the decline group, the old/new effect pattern did not change between T1 and T2. By contrast, for the stable group, the positive parietal old/new effect at T1 no longer appeared at T2, but a negative old/new effect was exhibited at frontal sites. This brain reorganization pattern could be a compensatory mechanism supporting strategic processes and allowing memory abilities to be maintained over time.

The Mozart Effect on the Episodic Memory of Healthy Adults Is Null, but Low-Functioning Older Adults May Be an Exception

Literature on the effects of passive music listening on cognitive performance is mixed, showing negative, null or positive results depending on cognitive domain, age group, temporal relation between music and task (background music vs. music before task, the latter known as Mozart effect), or listener-dependent variables such as musical preference. Positive effects of background music on the two components of episodic memory – item and source memory - for verbal materials seem robust and age-independent, and thus deserve further attention. In the current study, we investigated two potential enhancers of music effects on episodic memory: stopping music before task performance (Mozart effect) to eliminate music-related distraction and using preferred music to maximize reward. We ran a main study on a sample of 51 healthy younger adults, along with a pilot study with 12 older adults, divided into low- vs. high functioning according to cognitive performance in a screening test. Against our expectations, Bayesian analyses showed strong evidence that music had no advantage over silence or environmental sounds in younger adults. Preferred music had no advantage either, consistent with the possibility that music-related reward had no impact on episodic memory. Among older adults, low- but not high-functioning participants’ item memory was improved by music – especially by non-preferred music - compared to silence. Our findings suggest that, in healthy adults, prior-to-task music may be less effective than background music in episodic memory enhancement despite decreased distraction, possibly because reward becomes irrelevant when music is stopped before the task begins. Our pilot findings on older adults raise the hypothesis that low-functioning older participants relate to prior-to-task auditory stimulation in deviant ways when it comes to episodic memory enhancement.

The Association between Neighborhood Amenities and Cognitive Function: Role of Lifestyle Activities

Many of the modifiable risk factors for dementia are lifestyle-related, and multidomain interventions tailored to individual lifestyles are recommended to prevent cognitive decline and dementia. However, studies of the relationship between the environment and cognitive function have shown that cognitive disorders and dementia are more prevalent in rural areas than in urban areas. The purpose of this study was to clarify the role of lifestyle activities on the association between neighborhood amenities and cognitive function. Our data were measured between August 2011 and February 2012. Participants comprised 3786 older adults (mean age: 71.5 years, standard deviation (SD) = ±5.2). We categorized neighborhood amenities as institutional resources that promote cognitively beneficial activities such as physical activity. We calculated the Walk Score^® for all participants using their home address and divided them into three groups. We assessed their 12 lifestyle activities performed outdoors. Cognitive function was measured via Mini-Mental Status Exam, word list memory, attention, executive function, and processing speed. We found that participants who were more likely to report many lifestyle activities were more likely to have normal cognition, even in areas where neighborhood amenities were scarce. The clinical significance of this study is that increased lifestyle activity contributes to the prevention of cognitive decline.

The Role of Cognitive Reserve in Alzheimer's Disease and Aging: A Multi-Modal Imaging Review

Comforts in modern society have generally been associated with longer survival rates, enabling individuals to reach advanced age as never before in history. With the increase in longevity, however, the incidence of neurodegenerative diseases, especially Alzheimer's disease, has also doubled. Nevertheless, most of the observed variance, in terms of time of clinical diagnosis and progression, often remains striking. Only recently, differences in the social, educational and occupational background of the individual, as proxies of cognitive reserve (CR), have been hypothesized to play a role in accounting for such discrepancies. CR is a well-established concept in literature; lots of studies have been conducted in trying to better understand its underlying neural substrates and associated biomarkers, resulting in an incredible amount of data being produced. Here, we aimed to summarize recent relevant published work addressing the issue, gathering evidence for the existence of a common path across research efforts that might ease future investigations by providing a general perspective on the actual state of the arts. An innovative model is hereby proposed, addressing the role of CR across structural and functional evidences, as well as the potential implementation of non-invasive brain stimulation techniques in the causal validation of such theoretical frame.

Episodic memory boosting in older adults: exploring the association of encoding strategies and physical activity

Background: Contextual memory is susceptible to the effects of aging and its impairment compromises episodic memories and quality of life in older adults. Objective: Compare the effects of cognitive support on incidental contextual memory free recall and recognition with a naturalistic experimental paradigm and explore the association of encoding strategies and physical activity on memory improvement. Methods: Subjects (≥60 years, n = 52) were assigned to one of two encoding conditions for the contextual memory task: with or without an incidental associative instruction to encourage association of an item to its spatial context. Immediate free recall and recognition tests were run to assess the encoding instruction efficiency. The association of memory performance and physical activity was analyzed using the scores on the International Physical Activity Questionnaire (IPAQ) to subdivide each experimental group into Low IPAQ (below median) and High IPAQ (above median) subgroups. Results: The associative encoding instruction increased contextual memory free recall and recognition, with greater effects on free recall. The most robust associations between physical activity and contextual memory were also seen on free recall, in which higher levels of physical activity corresponded to increased baseline performance (non-associative encoding condition) and greater improvement of memory by the encoding support (associative encoding condition). Conclusion: Cognitive support at encoding can improve contextual memory free recall and recognition, suggesting they are prone to rehabilitation. Moreover, higher physical activity levels were positively associated with encoding strategies on contextual memory improvement, increasing the availability of latent process-based components of the cognitive reserve.

Motivational Influences on Performance Monitoring and Cognitive Control Across the Adult Lifespan

Cognitive control refers to the ability to regulate cognitive processing according to the tasks at hand, especially when these are demanding. It includes maintaining and updating relevant information in working memory, inhibiting irrelevant information, and flexibly switching between tasks. Performance monitoring denotes the processing of feedback from the environment and the detection of errors or other unexpected events and signals when cognitive control needs to be exerted. These two aspects of behavioral adaptation critically rely on the integrity of the frontal lobes, which are known to show pronounced age-related performance decrements. By contrast, there is evidence that processing of rewards remains relatively intact across the adult lifespan. Hence, motivation may play an important role in modulating or even counteracting age-related changes in cognitive control functions. To answer this question, neuroscientific data can be particularly useful to uncover potential underlying mechanisms beyond behavioral outcome. The aims of this article are twofold: First, to review and systematize the extant literature on how motivational incentives can modulate performance monitoring and cognitive control in young and older adults. Second, to demonstrate that important pieces of empirical data are currently missing for the evaluation of this central question, specifically in old age. Hence, we would like to stimulate further research uncovering potential mechanisms underlying motivation-cognition interactions in young and in particular in older adults and investigating whether or not those can help to ameliorate age-related impairments.

Neurocognitive development in socioeconomic context: Multiple mechanisms and implications for measuring socioeconomic status

Socioeconomic status (SES) has been linked to functioning across a variety of neurocognitive domains including language, memory, executive functioning, and social-emotional processing. We review these findings and discuss the ways in which socioeconomic context may shape neural processes such that these skills are supported by different neurobiological pathways in children from lower versus higher SES backgrounds. Moreover, we consider the mechanisms by which SES may be related to specific neurocognitive functions. Specifically, we focus on linguistic exposure and stress as two main pathways through which SES could influence neurocognitive processes and shape relations between the neural and behavioral levels of functioning. Finally, suggestions for conceptualizing and measuring SES in future work are offered.

Socioeconomic status, white matter, and executive function in children

BACKGROUND

A growing body of evidence links socioeconomic status (SES) to children's brain structure. Few studies, however, have specifically investigated relations of SES to white matter structure. Further, although several studies have demonstrated that family SES is related to development of brain areas that support executive functions (EF), less is known about the role that white matter structure plays in the relation of SES to EF. One possibility is that white matter differences may partially explain SES disparities in EF (i.e., a mediating relationship). Alternatively, SES may differentially shape brain-behavior relations such that the relation of white matter structure to EF may differ as a function of SES (i.e., a moderating relationship).

METHOD

In a diverse sample of 1082 children and adolescents aged 3-21 years, we examined socioeconomic disparities in white matter macrostructure and microstructure. We further investigated relations between family SES, children's white matter volume and integrity in tracts supporting EF, and performance on EF tasks.

RESULTS

Socioeconomic status was associated with fractional anisotropy (FA) and volume in multiple white matter tracts. Additionally, family income moderated the relation between white matter structure and cognitive flexibility. Specifically, across multiple tracts of interest, lower FA or lower volume was associated with reduced cognitive flexibility among children from lower income families. In contrast, children from higher income families showed preserved cognitive flexibility in the face of low white matter FA or volume. SES factors did not mediate or moderate links between white matter and either working memory or inhibitory control.

CONCLUSIONS

This work adds to a growing body of literature suggesting that the socioeconomic contexts in which children develop not only shape cognitive functioning and its underlying neurobiology, but may also shape the relations between brain and behavior.

Cognitive Decline in Patients with Chronic Hydrocephalus and Normal Aging: 'Growing into Deficits'

BACKGROUND/AIM

To explore the theory of 'growing into deficits', a concept known from developmental neurology, in a series of cases with chronic hydrocephalus (CH).

METHODS

Patients were selected from the Amsterdam Dementia Cohort and underwent extensive dementia screening.

RESULTS

Twelve patients with CH were selected, in whom Alzheimer's disease was considered unlikely, based on biomarker information and follow-up. Mean Mini-Mental State Examination score was 24 (range 7-30). Most patients were functioning on a level of mild dementia [Clinical Dementia Rating score of 0.5 in 8/11 (66.7%) patients]. On neuropsychological examination, memory and executive functions, as well as processing speed were most frequently impaired.

CONCLUSION

In our opinion, the theory of 'growing into deficits' shows a parallel with the clinical course of CH and normal aging when Alzheimer's disease was considered very unlikely, because most of these patients were functioning well for a very large part of their lives. The altered cerebrospinal fluid dynamics might make the brain more vulnerable to aging-related changes, leading to a faster cognitive decline in CH patients compared to healthy subjects, especially in case of concomitant brain damage such as traumatic brain injury or meningitis.

Functional neuroimaging of normal aging: Declining brain, adapting brain

Early functional neuroimaging research on normal aging brain has been dominated by the interest in cognitive decline. In this framework the age-related compensatory recruitment of prefrontal cortex, in terms of executive system or reduced lateralization, has been established. Further details on these compensatory mechanisms and the findings reflecting cognitive decline, however, remain the matter of intensive investigations. Studies in another framework where age-related neural alteration is considered adaptation to the environmental change are recently burgeoning and appear largely categorized into three domains. The age-related increase in activation of the sensorimotor network may reflect the alteration of the peripheral sensorimotor systems. The increased susceptibility of the network for the mental-state inference to the socioemotional significance may be explained by the age-related motivational shift due to the altered social perception. The age-related change in activation of the self-referential network may be relevant to the focused positive self-concept of elderly driven by a similar motivational shift. Across the domains, the concept of the self and internal model may provide the theoretical bases of this adaptation framework. These two frameworks complement each other to provide a comprehensive view of the normal aging brain.

Environment as 'Brain Training': A review of geographical and physical environmental influences on cognitive ageing

Global ageing demographics coupled with increased urbanisation pose major challenges to the provision of optimal living environments for older persons, particularly in relation to cognitive health. Although animal studies emphasize the benefits of enriched environments for cognition, and brain training interventions have shown that maintaining or improving cognitive vitality in older age is possible, our knowledge of the characteristics of our physical environment which are protective for cognitive ageing is lacking. The present review analyses different environmental characteristics (e.g. urban vs. rural settings, presence of green) in relation to cognitive performance in ageing. Studies of direct and indirect associations between physical environment and cognitive performance are reviewed in order to describe the evidence that our living contexts constitute a measurable factor in determining cognitive ageing.

Relationship of medial temporal lobe atrophy, APOE genotype, and cognitive reserve in preclinical Alzheimer's disease

This study evaluated the utility of baseline and longitudinal magnetic resonance imaging (MRI) measures of medial temporal lobe brain regions collected when participants were cognitively normal and largely in middle age (mean age 57 years) to predict the time to onset of clinical symptoms associated with mild cognitive impairment (MCI). Furthermore, we examined whether the relationship between MRI measures and clinical symptom onset was modified by apolipoprotein E (ApoE) genotype and level of cognitive reserve (CR). MRI scans and measures of CR were obtained at baseline from 245 participants who had been followed for up to 18 years (mean follow-up 11 years). A composite score based on reading, vocabulary, and years of education was used as an index of CR. Cox regression models showed that lower baseline volume of the right hippocampus and smaller baseline thickness of the right entorhinal cortex predicted the time to symptom onset independently of CR and ApoE-ɛ4 genotype, which also predicted the onset of symptoms. The atrophy rates of bilateral entorhinal cortex and amygdala volumes were also associated with time to symptom onset, independent of CR, ApoE genotype, and baseline volume. Only one measure, the left entorhinal cortex baseline volume, interacted with CR, such that smaller volumes predicted symptom onset only in individuals with lower CR. These results suggest that MRI measures of medial temporal atrophy, ApoE-ɛ4 genotype, and the protective effects of higher CR all predict the time to onset of symptoms associated with MCI in a largely independent, additive manner during the preclinical phase of Alzheimer's disease.

Conflict Monitoring Across the Life Span

Errors can play a major role for optimizing subsequent performance: Response conflict associated with (near) errors signals the need to recruit additional control resources to minimize future conflict. However, so far it remains open whether children and older adults also adjust their performance as a function of preceding response conflict. To examine the life span development of conflict detection and resolution, response conflict was elicited during a task-switching paradigm. Electrophysiological correlates of conflict detection for correct and incorrect responses and behavioral indices of post-error adjustments were assessed while participants in four age groups were asked to focus on either speed or accuracy. Despite difficulties in resolving response conflict, the ability to detect response conflict as indexed by the Ne/ERN component was expected to mature early and be preserved in older adults. As predicted, reliable Ne/ERN peaks were detected across age groups. However, only for adults Ne/ERN amplitudes associated with errors were larger compared to Nc/CRN amplitudes for correct trials under accuracy instructions, suggesting an ongoing maturation in the ability to differentiate levels of response conflict. Behavioral interference costs were considerable in both children and older adults. Performance for children and older adults deteriorated rather than improved following errors, in line with intact conflict detection, but impaired conflict resolution. Thus, participants in all age groups were able to detect response conflict, but only young adults successfully avoided subsequent conflict by up-regulating control.

Relating education, brain structure, and cognition: the role of cardiovascular disease risk factors

The protective effect of education on cognitive and brain health is well established. While the direct effects of individual cardiovascular disease (CVD) risk factors (i.e., hypertension, smoking, diabetes, and obesity) on cerebral structure have been investigated, little is understood about the possible interaction between the protective effect of education and the deleterious effects of CVD risk factors in predicting brain ageing and cognition. Using data from the PATH Through Life study (N = 266), we investigated the protective effect of education on cerebral structure and function and tested a possible mediating role of CVD risk factors. Higher education was associated with larger regional grey/white matter volumes in the prefrontal cortex in men only. The association between education and cognition was mediated by brain volumes but only for grey matter and only in relation to information processing speed. CVD risk factors did not mediate the association between regional volumes and cognition. This study provides additional evidence in support for a protective effect of education on cerebral structures and cognition. However, it does not provide support for a mediating role of CVD risk factors in these associations.

Efficiency, capacity, compensation, maintenance, plasticity: emerging concepts in cognitive reserve

Cognitive reserve (CR) is a concept meant to account for the frequent discrepancy between an individual's measured level of brain pathology and her expected cognitive performance. It is particularly important within the context of aging and dementia, but has wider applicability to all forms of brain damage. As such, it has intimate links to related compensatory and neuroprotective concepts, as well as to the related notion of brain reserve. In this article, we introduce the concept of cognitive reserve and explicate its potential cognitive and neural implementation. We conclude that cognitive reserve is compatible and complementary with many related concepts, but that each much draw sharper conceptual boundaries in order to truly explain preserved cognitive function in the face of aging or brain damage.

The cognitive aging of episodic memory: a view based on the event-related brain potential

A cardinal feature of older-adult cognition is a decline, relative to the young, in the encoding and retrieval of personally relevant events, i.e., episodic memory (EM). A consensus holds that familiarity, a relatively automatic feeling of knowing that can support recognition-memory judgments, is preserved with aging. By contrast, recollection, which requires the effortful, strategic recovery of contextual detail, declines as we age. Over the last decade, event-related brain potential (ERPs) have become increasingly important tools in the study of the aging of EM, because a few, well-researched EM effects have been associated with the cognitive processes thought to underlie successful EM performance. EM effects are operationalized by subtracting the ERPs elicited by correctly rejected, new items from those to correctly recognized, old items. Although highly controversial, the mid-frontal effect (a positive component between ∼300 and 500 ms, maximal at fronto-central scalp sites) is thought to reflect familiarity-based recognition. A positivity between ∼500 and 800 ms, maximal at left-parietal scalp, has been labeled the left-parietal EM effect. A wealth of evidence suggests that this brain activity reflects recollection-based retrieval. Here, I review the ERP evidence in support of the hypothesis that familiarity is maintained while recollection is compromised in older relative to young adults. I consider the possibility that the inconsistency in findings may be due to individual differences in performance, executive function, and quality of life indices, such as socio-economic status.

A dynamic auditory-cognitive system supports speech-in-noise perception in older adults

Understanding speech in noise is one of the most complex activities encountered in everyday life, relying on peripheral hearing, central auditory processing, and cognition. These abilities decline with age, and so older adults are often frustrated by a reduced ability to communicate effectively in noisy environments. Many studies have examined these factors independently; in the last decade, however, the idea of an auditory-cognitive system has emerged, recognizing the need to consider the processing of complex sounds in the context of dynamic neural circuits. Here, we used structural equation modeling to evaluate the interacting contributions of peripheral hearing, central processing, cognitive ability, and life experiences to understanding speech in noise. We recruited 120 older adults (ages 55-79) and evaluated their peripheral hearing status, cognitive skills, and central processing. We also collected demographic measures of life experiences, such as physical activity, intellectual engagement, and musical training. In our model, central processing and cognitive function predicted a significant proportion of variance in the ability to understand speech in noise. To a lesser extent, life experience predicted hearing-in-noise ability through modulation of brainstem function. Peripheral hearing levels did not significantly contribute to the model. Previous musical experience modulated the relative contributions of cognitive ability and lifestyle factors to hearing in noise. Our models demonstrate the complex interactions required to hear in noise and the importance of targeting cognitive function, lifestyle, and central auditory processing in the management of individuals who are having difficulty hearing in noise.

ERP Evidence for Scarce Rule Representation in Older Adults Following Short, but Not Long Preparatory Intervals

The focus of the present study was to examine the cognitive processes comprising advance preparation – rule representation, task-set updating, and task-set reconfiguration – in young (20–25 years) and older adults (61–83 years). Specifically, this study aimed at further characterizing age-related differences in advance preparation, and evaluating how additional time to prepare might reduce behavioral costs in older adults. In line with previous findings, reaction time mixing costs were slightly larger for older compared to young adults, whereas behavioral switch costs were age-invariant. Following short preparation (600 ms), smaller antero-frontal event-related potential (ERP) correlates of rule representation were associated with pronounced congruency costs in older adults. Centro-parietal ERP correlates of task-set updating and task-set reconfiguration were not delayed, but smaller in magnitude for older compared to young adults. Longer preparation (1200 ms) enabled older adults to re-activate relevant task rules, as evident in reduced congruency costs, and temporally sustained ERP correlates of task-set updating and rule representation well beyond 600 ms. Age-invariant switch costs appear related to additional, potentially compensatory frontal activity recruited by older adults to overcome difficulties in task-set reconfiguration.

The brain's orienting response (novelty P3) in patients with unilateral temporal lobe resections

The brain's orienting response is a biologically primitive, yet critical cognitive function necessary for survival. Though based on a wide network of brain regions, the lateral prefrontal cortex and posterior hippocampus are thought to play essential roles. Indeed, damage to these regions results in abnormalities of the novelty P3 or P3a, an event-related potential (ERP) sign of the orienting response. Like other ubiquitous markers of orienting, such as the galvanic skin response, the P3a habituates when novel events are repeated. Here, we assessed habituation of the P3a in patients who had undergone unilateral anteromedial resection of the medial temporal lobe (AMTL), including the entire hippocampus, for relief of pharmacologically intractable epilepsy. Eight left- and 8 right-AMTL patients and 16 age- and education-matched controls heard frequent standard tones, infrequent targets (requiring reaction times) and equally infrequent, unique novel, environmental sounds. The novel sounds repeated 2 blocks after their first presentation. In controls, novel repetition engendered a reduction in P3a amplitude, but this was not the case in either left- or right-AMTL patients. We conclude that bilaterally intact hippocampi are necessary for the brain to appreciate that a repetition of a novel sound has occurred, perhaps due to disruptions in ipsilateral hippocampal-prefrontal pathways and/or between the left and right hippocampi.

Age-related changes in electrophysiological and neuropsychological indices of working memory, attention control, and cognitive flexibility

Older adults exhibit great variability in their cognitive abilities, with some maintaining high levels of performance on executive control tasks and others showing significant deficits. Previous event-related potential (ERP) work has shown that some of these performance differences are correlated with persistence of the novelty/frontal P3 in older adults elicited by task-relevant events, presumably reflecting variability in the capacity to suppress orienting to unexpected but no longer novel events. In recent ERP work in young adults, we showed that the operation-span (OSPAN) task (a measure of attention control) is predictive of the ability of individuals to keep track of stimulus sequencing and to maintain running mental representations of task stimuli, as indexed by the parietally distributed P300 (or P3b). Both of these phenomena reflect aspects of frontal function (cognitive flexibility and attention control, respectively). To investigate these phenomena we sorted both younger and older adults into low- and high-working memory spans and low- and high-cognitive flexibility subgroups, and examined ERPs during an equal-probability choice reaction time task. For both age groups (a) participants with high OSPAN scores were better able to keep track of stimulus sequencing, as indicated by their smaller P3b to sequential changes; and (b) participants with lower cognitive flexibility had larger P3a than their high-scoring counterparts. However, these two phenomena did not interact suggesting that they manifest dissociable control mechanisms. Further, the fact that both effects are already visible in younger adults suggests that at least some of the brain mechanisms underlying individual differences in cognitive aging may already operate early in life.

Effects of socioeconomic status on brain development, and how cognitive neuroscience may contribute to levelling the playing field

The study of socioeconomic status (SES) and the brain finds itself in a circumstance unusual for Cognitive Neuroscience: large numbers of questions with both practical and scientific importance exist, but they are currently under-researched and ripe for investigation. This review aims to highlight these questions, to outline their potential significance, and to suggest routes by which they might be approached. Although remarkably few neural studies have been carried out so far, there exists a large literature of previous behavioural work. This behavioural research provides an invaluable guide for future neuroimaging work, but also poses an important challenge for it: how can we ensure that the neural data contributes predictive or diagnostic power over and above what can be derived from behaviour alone? We discuss some of the open mechanistic questions which Cognitive Neuroscience may have the power to illuminate, spanning areas including language, numerical cognition, stress, memory, and social influences on learning. These questions have obvious practical and societal significance, but they also bear directly on a set of longstanding questions in basic science: what are the environmental and neural factors which affect the acquisition and retention of declarative and nondeclarative skills? Perhaps the best opportunity for practical and theoretical interests to converge is in the study of interventions. Many interventions aimed at improving the cognitive development of low SES children are currently underway, but almost all are operating without either input from, or study by, the Cognitive Neuroscience community. Given that longitudinal intervention studies are very hard to set up, but can, with proper designs, be ideal tests of causal mechanisms, this area promises exciting opportunities for future research.

Changes in familiarity and recollection across the lifespan: an ERP perspective

The ability to recognize previous experience depends on two neurocognitive processes, familiarity, fast-acting and relatively automatic, and recollection, slower-acting and more effortful. Familiarity appears to mature relatively early in development and is maintained with aging, whereas recollection shows protracted development and deteriorates with aging. To assess this model, ERP and behavioral data were recorded in children (9-10 years), adolescents (13-14), young (20-30) and older (65-85) adults during a recognition memory task in which the same items were studied and tested over four cycles. Participants decided whether each item was old or new and then whether the decision was associated with (Remember, R) or without (Know, K) contextual detail. Memory sensitivity was greatest in young adults, although all groups showed increases in memory sensitivity and R judgments with repetition. Familiarity-based processes (mid-frontal episodic memory, EM, effect) appeared to be used by adolescents, young and older adults, but apparently not to the same extent by children. Recollection-based processes (parietal EM effect) were recruited by children, adolescents and young adults, but to a much lesser extent by older adults. Repetition enhanced the parietal effect in all but older adults. However, post-hoc analyses indicated that reduced recollective processing was confined to poor-performing older adults. By contrast, children appeared to rely mainly on recollection concordant with their conservative decision criteria across tests. We conclude that episodic-memory development reflects the increasingly flexible and interchangeable use of familiarity and recollection with a breakdown in the latter at older ages, perhaps limited to poor-performing older adults.

Socioeconomic status and the developing brain

Childhood socioeconomic status (SES) is associated with cognitive achievement throughout life. How does SES relate to brain development, and what are the mechanisms by which SES might exert its influence? We review studies in which behavioral, electrophysiological and neuroimaging methods have been used to characterize SES disparities in neurocognitive function. These studies indicate that SES is an important predictor of neurocognitive performance, particularly of language and executive function, and that SES differences are found in neural processing even when performance levels are equal. Implications for basic cognitive neuroscience and for understanding and ameliorating the problems related to childhood poverty are discussed.

Neuroanatomical correlates of aging, cardiopulmonary fitness level, and education

Fitness and education may protect against cognitive impairments in aging. They may also counteract age-related structural changes within the brain. Here we analyzed volumetric differences in cerebrospinal fluid and gray and white matter, along with neuropsychological data, in adults differing in age, fitness, and education. Cognitive performance was correlated with fitness and education. Voxel-based morphometry was used for a whole-brain analysis of structural magnetic resonance images. We found age-related losses in gray and white matter in medial-temporal, parietal, and frontal areas. As in previous work, fitness within the old correlated with preserved gray matter in the same areas. In contrast, higher education predicted preserved white matter in inferior frontal areas. These data suggest that fitness and education may both be predictive of preserved cognitive function in aging through separable effects on brain structure.