Age-related changes in the efficiency of cognitive processing across the life span

Parental education, cognition and functional connectivity of the salience network

The aim was to investigate the association of parental education at birth with cognitive ability in childhood and young adulthood and determine, whether functional connectivity of the salience network underlies this association. We studied participants of the Czech arm of the European Longitudinal Study of Pregnancy and Childhood who underwent assessment of their cognitive ability at age 8 (Wechsler Intelligence Scale for Children) and 28/29 years (Wechsler Adult Intelligence Scale) and measurement with resting state functional MRI at age 23/24. We estimated the associations of parental education with cognitive ability and functional connectivity between the seeds in the salience network and other voxels in the brain. We found that lower education of both mothers and fathers was associated with lower verbal IQ, performance IQ and full-scale IQ of the offspring at age 8. Only mother´s education was associated with performance IQ at age 28/29. Lower mother´s education correlated with greater functional connectivity between the right rostral prefrontal cortex and a cluster of voxels in the occipital cortex, which, in turn, was associated with lower performance IQ at age 28/29. We conclude that the impact of parental education, particularly father´s, on offspring´s cognitive ability weakens during the lifecourse. Functional connectivity between the right rostral prefrontal cortex and occipital cortex may be a biomarker underlying the transmission of mother´s education on performance IQ of their offspring.

Age effect in expert cognitive flexibility in Guinea baboons (Papio papio)

Cognitive flexibility in non-human primates is traditionally measured with the conceptual set shifting task (CSST). In our laboratory, Guinea baboons (N = 24) were continuously tested with a CSST task during approximately 10 years. Our task involved the presentation of three stimuli on a touch screen all made from 3 possible colours and 3 shapes. The subjects had to touch the stimulus containing the stimulus dimension (e.g., green) that was constantly rewarded until the stimulus dimension changed. Analysis of perseveration responses, scores and response times collected during the last two years of testing (approximately 1.6 million trials) indicate (1) that the baboons have developed an "expert" form of cognitive flexibility and (2) that their performance was age-dependent, it was at a developing stage in juveniles, optimal in adults, declining in middle-aged, and strongly impaired in the oldest age group. A direct comparison with the data collected by Bonté , Flemming & Fagot (2011) on some of the same baboons and same task as in the current study indicates that (3) the performance of all age groups has improved after 10 years of training, even for the now old individuals. All these data validate the use of non-human primates as models of human cognitive flexibility and suggest that cognitive flexibility in humans has a long evolutionary history.

Cognitive Control Challenge Task Across the Lifespan

Meeting everyday challenges and responding in a goal-directed manner requires both the ability to maintain the current task set in face of distractors-stable cognitive control, and the ability to flexibly generate or switch to a new task set when environmental requirements change-flexible cognitive control. While studies show that the development varies across individual component processes supporting cognitive control, little is known about changes in complex stable and flexible cognitive control across the lifespan. In the present study, we used the newly developed Cognitive Control Challenge Task (C3T) to examine the development of complex stable and flexible cognitive control across the lifespan and to gain insight into their interdependence. A total of 340 participants (229 women, age range 8-84 years) from two samples participated in the study, in which they were asked to complete the C3T along with a series of standard tests of individual components of cognitive control. The results showed that the development of both stable and flexible complex cognitive control follows the expected inverted U-curve. In contrast, the indeces of task set formation and task set switching cost increase linearly across the lifespan, suggesting that stable and flexible complex cognitive control are subserved by separable cognitive systems with different developmental trajectories. Correlations with standard cognitive tests indicate that complex cognitive control captured by the C3T engages a broad range of cognitive abilities, such as working memory and planning, and reflects global processing speed, jointly suggesting that the C3T is an effective test of complex cognitive control that has both research and diagnostic potential.

Neuro-Behavioral Correlates of Executive Dysfunctions in Dyslexia Over Development From Childhood to Adulthood

Dyslexia is a neurobiological learning disability in the reading domain that has symptoms in early childhood and persists throughout life. Individuals with dyslexia experience difficulties in academia and cognitive and emotional challenges that can affect wellbeing. Early intervention is critical to minimize the long-term difficulties of these individuals. However, the behavioral and neural correlates which predict dyslexia are challenging to depict before reading is acquired. One of the precursors for language and reading acquisition is executive functions (EF). The present review aims to highlight the current atypicality found in individuals with dyslexia in the domain of EF using behavioral measures, brain mapping, functional connectivity, and diffusion tensor imaging along development. Individuals with dyslexia show EF abnormalities in both behavioral and neurobiological domains, starting in early childhood that persist into adulthood. EF impairment precedes reading disability, therefore adding an EF assessment to the neuropsychological testing is recommended for early intervention. EF training should also be considered for the most comprehensive outcomes.

An Adaptable, Open-Access Test Battery to Study the Fractionation of Executive-Functions in Diverse Populations

The umbrella-term 'executive functions' (EF) includes various domain-general, goal-directed cognitive abilities responsible for behavioral self-regulation. The influential unity and diversity model of EF posits the existence of three correlated yet separable executive domains: inhibition, shifting and updating. These domains may be influenced by factors such as socioeconomic status (SES) and culture, possibly due to the way EF tasks are devised and to biased choice of stimuli, focusing on first-world testees. Here, we propose a FREE (Free Research Executive Function Evaluation) test battery that includes two open-access tasks for each of the three abovementioned executive domains to allow latent variables to be obtained. The tasks were selected from those that have been shown to be representative of each domain, that are not copyrighted and do not require special hardware/software to be administered. These tasks were adapted for use in populations with varying SES/schooling levels by simplifying tasks/instructions and using easily recognized stimuli such as pictures. Items are answered verbally and tasks are self-paced to minimize interference from individual differences in psychomotor and perceptual speed, to better isolate executive from other cognitive abilities. We tested these tasks on 146 early adolescents (aged 9-15 years) of both sexes and varying SES, because this is the age group in which the executive domains of interest become distinguishable and in order to confirm that SES effects were minimized. Performance was determined by Rate Correct Scores (correct answers divided by total time taken to complete blocks/trial), which consider speed-accuracy trade-offs. Scores were sensitive to the expected improvement in performance with age and rarely/inconsistently affected by sex and SES, as expected, with no floor or ceiling effects, or skewed distribution, thus suggesting their adequacy for diverse populations in these respects. Using structural equation modeling, evidence based on internal structure was obtained by replicating the three correlated-factor solution proposed by the authors of the model. We conclude that the FREE test battery, which is open access and described in detail, holds promise as a tool for research that can be adapted for a wide range of populations, as well as altered and/or complemented in coming studies.

Executive Functions in Late Adolescence and Early Adulthood and Their Relationship with Risk-Taking Behavior

Executive functions (EF) continue developing throughout adolescence, with immaturity in EF theorized to underlie risk-taking. 129 older adolescents and young adults (aged 17 to 22 years) were assessed using a battery of cool and hot EF tasks, and a behavioral measure of risk-taking propensity. Minimal age-related differences in EF performance were evident, confirming they were largely functionally mature by mid-adolescence. Inconsistent with the predictions of imbalance models of adolescent development, weaker EF was not associated with greater risk-taking propensity. The findings suggest that during later adolescence and early adulthood, not all forms of risk-taking are associated with EF.

Reciprocal Copy Number Variations at 22q11.2 Produce Distinct and Convergent Neurobehavioral Impairments Relevant for Schizophrenia and Autism Spectrum Disorder

BACKGROUND

22q11.2 deletions and duplications are copy number variations (CNVs) that predispose to developmental neuropsychiatric disorders. Both CNVs are associated with autism spectrum disorder (ASD), while the deletion confers disproportionate risk for schizophrenia. Neurobehavioral profiles associated with these reciprocal CNVs in conjunction with brain imaging measures have not been reported.

METHODS

We profiled the impact of 22q11.2 CNVs on neurobehavioral measures relevant to ASD and psychosis in 106 22q11.2 deletion carriers, 38 22q11.2 duplication carriers, and 82 demographically matched healthy control subjects. To determine whether brain-behavior relationships were altered in CNV carriers, we further tested for interactions between group and regional brain structure on neurobehavioral domains.

RESULTS

Cognitive deficits were observed in both CNV groups, with the lowest IQs in deletion carriers. ASD and dimensionally measured ASD traits were elevated in both CNV groups; however, duplication carriers exhibited increased stereotypies compared to deletion carriers. Moreover, discriminant analysis using ASD subdomains distinguished between CNV cases with 76% accuracy. Both psychotic disorder diagnosis and dimensionally measured positive and negative symptoms were elevated in deletion carriers. Finally, healthy control subjects showed an inverse relationship between processing speed and cortical thickness in heteromodal association areas, which was absent in both CNV groups.

CONCLUSIONS

22q11.2 CNVs differentially modulate intellectual functioning and psychosis-related symptomatology but converge on broad ASD-related symptomatology. However, subtle differences in ASD profiles distinguish CNV groups. Processing speed impairments, coupled with the lack of normative relationship between processing speed and cortical thickness in CNV carriers, implicate aberrant development of the cortical mantle in the pathology underlying impaired processing speed ability.

Relations between gross motor skills and executive functions, controlling for the role of information processing and lapses of attention in 8-10 year old children

This study aimed to systematically investigate the relation between gross motor skills and aspects of executive functioning (i.e. verbal working memory, visuospatial working memory, response inhibition and interference control) in 8-10 year old children. Additionally, the role of information processing (speed and variability) and lapses of attention in the relation between gross motor skills and executive functions was investigated. Data of 732 Dutch children from grade 3 and 4 were analyzed (50.0% boys, 50.4% grade 3, age = 9.16 ± 0.64 years). Gross motor skills were assessed using three items of the Körper Koordinationstest für Kinder and one item of the Bruininks-Oseretsky test of Motor Proficiency, Second Edition. Executive functions were assessed using the Wechsler Digit Span task (verbal working memory), the Visuospatial Memory task (visuospatial working memory), the Stop Signal task (response inhibition) and a modified version of the Flanker task (interference control). Information processing and lapses of attention were obtained by applying an ex-Gaussian analysis on go trials of the Stop Signal task. Multilevel regression analysis showed that gross motor skills were significantly related to verbal working memory, visuospatial working memory and response inhibition, but not to interference control. Lapses of attention was a significant predictor for all executive functions, whereas processing speed was not. Variability in processing speed was only predictive for visuospatial working memory. After controlling for information processing and lapses of attention, gross motor skills were only significantly related to visuospatial working memory and response inhibition. The results suggest that after controlling for information processing and lapses of attention, gross motor skills are related to aspects of executive functions that are most directly involved in, and share common underlying processes with, gross motor skills.

A Non-linear Relationship Between Selective Attention and Associated ERP Markers Across the Lifespan

The ability to selectively attend to task-relevant information increases throughout childhood and decreases in older age. Here, we intended to investigate these opposing developmental trajectories, to assess whether gains and losses early and late in life are associated with similar or different electrophysiological changes, and to get a better understanding about the development in middle-adulthood. We (re-)analyzed behavioral and electrophysiological data of 211 participants, who performed a colored Flanker task while their Electroencephalography (EEG) was recorded. Participants were subdivided into six groups depending on their age, ranging from 8 to 83 years. We analyzed response speed and accuracy as well as the event replated potential (ERP) components P1 and N1, associated with visual processing and attention, N2 as marker of interference suppression and cognitive control, and P3 as a marker of cognitive updating and stimulus categorization. Response speed and accuracy were low early and later in life, with peak performance in young adults. Similarly, ERP latencies of all components and P1 and N1 amplitudes followed a u-shape pattern with shortest latencies and smallest amplitudes occurring in middle-age. N2 amplitudes were larger in children, and for incongruent stimuli in adults middle-aged and older. P3 amplitudes showed a parietal-to-frontal shift with age. Further, group-wise regression analyses suggested that children’s performance depended on cognitive processing speed, while older adults’ performance depended on cognitive resources. Together these results imply that different mechanisms restrict performance early and late in life and suggest a non-linear relationship between electrophysiological markers and performance in the Flanker task across the lifespan.

The Structure of Speed of Processing Across Cultures

We examined whether a general processing factor emerges when using response times for cognitive processing tasks and whether such a factor is valid across three different cultural groups (Chinese, Canadian, and Greek). Three hundred twenty university students from Canada (n = 115), China (n = 110), and Cyprus (n = 95) were assessed on an adaptation of the Das-Naglieri Cognitive Assessment System (D-N CAS; Naglieri & Das, 1997). Three alternative models were contrasted: a distinct abilities processing speed model (Model 1) that is dictated by the latent four cognitive factors of planning, attention, simultaneous and successive (PASS) processing, a unitary ability processing speed model (Model 2) that is dictated by the response time nature of all measures, and a bifactor model (Model 3) which included the latent scores of Models 1 and 2 and served as the full model. Results of structural equation modeling showed that (a) the model representing processing speed as a collection of four cognitive processes rather than a unitary processing speed factor was the most parsimonious, and (b) the loadings of the obtained factors were invariant across the three cultural groups. These findings enhance our understanding of the nature of speed of processing across diverse cultures and suggest that even when cognitive processes (i.e., PASS) are operationalized with response time measures, the processing component dominates speed.

Inhibition and Updating, but Not Switching, Predict Developmental Dyslexia and Individual Variation in Reading Ability

To elucidate the core executive function profile (strengths and weaknesses in inhibition, updating, and switching) associated with dyslexia, this study explored executive function in 27 children with dyslexia and 29 age matched controls using sensitive z-mean measures of each ability and controlled for individual differences in processing speed. This study found that developmental dyslexia is associated with inhibition and updating, but not switching impairments, at the error z-mean composite level, whilst controlling for processing speed. Inhibition and updating (but not switching) error composites predicted both dyslexia likelihood and reading ability across the full range of variation from typical to atypical. The predictive relationships were such that those with poorer performance on inhibition and updating measures were significantly more likely to have a diagnosis of developmental dyslexia and also demonstrate poorer reading ability. These findings suggest that inhibition and updating abilities are associated with developmental dyslexia and predict reading ability. Future studies should explore executive function training as an intervention for children with dyslexia as core executive functions appear to be modifiable with training and may transfer to improved reading ability.

How Do Children Deal With Conflict? A Developmental Study of Sequential Conflict Modulation

This study examined age-related differences in sequential conflict modulation (SCM), elicited in three tasks requiring the inhibition of pre-potent responses; a Simon task, an S-R compatibility (SRC) task and a hybrid Choice-reaction/NoGo task. The primary focus was on age-related changes in performance changes following a conflict trial. A secondary aim was to assess whether SCM follows different developmental trajectories depending on the type of conflict elicited by the tasks. The tasks were presented to three different groups of participants with an age range between 7- to 25-years-one group of participants for each task. For each task, the response-to-stimulus interval (RSI) was manipulated (50 vs. 500 ms) across trial blocks to assess time-dependent changes in conflict modulation. The results showed SCM for all three tasks, although the specific patterns differed between tasks and RSIs. Importantly, the magnitude of SCM decreased with advancing age, but this developmental trend did not survive when considering age-group differences in basic response speed. The current results contribute to the emerging evidence suggesting that patterns of SCM are task specific and were interpreted in terms of multiple bottom-up control mechanisms.

Executive Functions in Older Adults With Autism Spectrum Disorder: Objective Performance and Subjective Complaints

Although deficits in Executive Functioning (EF) are reported frequently in young individuals with Autism Spectrum Disorders (ASD), they remain relatively unexplored later in life (>50 years). We studied objective performance on EF measures (Tower of London, Zoo map, phonetic/semantic fluency) as well as subjective complaints (self- and proxy reported BRIEF) in 36 ASD and 36 typically developed individuals (n = 72). High functioning older adults with ASD reported EF-impairments in metacognition, but did not deviate in EF task performance, except for a longer execution time of the Tower of London. The need for additional time to complete daily tasks may contribute to impairments in daily life and may be correlated to a higher level of experienced EF-difficulties in ASD.

Executive dysfunction in patients with chronic primary insomnia treated with clonazepam

Clonazepam (CNZ) is a drug used for insomnia treatment. Our objective was to search CNZ effects on executive functions (EF) in patients with chronic primary insomnia (CPI)-CNZ treated. Ninety participants were studied divided into three groups: a group of patients with CPI only (n = 30), a group of patients with CPI-CNZ treated (n = 30) and a healthy control drug-free subjects group (n = 30). EF were examined by means of E-Prime and by the Tower of London tests. Data of the EF were compared between groups, and correlation calculations between EF and CNZ dose were performed. Patients with CPI-CNZ treated showed more deleterious effects on EF (attention, inhibition, working memory, planning, cognitive flexibility, and monitoring) than patients with CPI only. Attention and cognitive flexibility correlated with CNZ dose. In conclusion, CNZ treatment was associated with deficits in some EF in patients with CPI-CNZ treated compared to CPI only and controls. We found a dose dependency between CNZ and some EF deficits.

Involuntary Capture and Voluntary Reorienting of Attention Decline in Middle-Aged and Old Participants

The main aim of this study was to examine the effects of aging on event-related brain potentials (ERPs) associated with the automatic detection of unattended infrequent deviant and novel auditory stimuli (Mismatch Negativity, MMN) and with the orienting to these stimuli (P3a component), as well as the effects on ERPs associated with reorienting to relevant visual stimuli (Reorienting Negativity, RON). Participants were divided into three age groups: (1) Young: 21-29 years old; (2) Middle-aged: 51-64 years old; and (3) Old: 65-84 years old. They performed an auditory-visual distraction-attention task in which they were asked to attend to visual stimuli (Go, NoGo) and to ignore auditory stimuli (S: standard, D: deviant, N: novel). Reaction times (RTs) to Go visual stimuli were longer in old and middle-aged than in young participants. In addition, in all three age groups, longer RTs were found when Go visual stimuli were preceded by novel relative to deviant and standard auditory stimuli, indicating a distraction effect provoked by novel stimuli. ERP components were identified in the Novel minus Standard (N-S) and Deviant minus Standard (D-S) difference waveforms. In the N-S condition, MMN latency was significantly longer in middle-aged and old participants than in young participants, indicating a slowing of automatic detection of changes. The following results were observed in both difference waveforms: (1) the P3a component comprised two consecutive phases in all three age groups-an early-P3a (e-P3a) that may reflect the orienting response toward the irrelevant stimulation and a late-P3a (l-P3a) that may be a correlate of subsequent evaluation of the infrequent unexpected novel or deviant stimuli; (2) the e-P3a, l-P3a, and RON latencies were significantly longer in the Middle-aged and Old groups than in the Young group, indicating delay in the orienting response to and the subsequent evaluation of unattended auditory stimuli, and in the reorienting of attention to relevant (Go) visual stimuli, respectively; and (3) a significantly smaller e-P3a amplitude in Middle-aged and Old groups, indicating a deficit in the orienting response to irrelevant novel and deviant auditory stimuli.

From junior to senior Pinocchio: A cross-sectional lifespan investigation of deception

We present the first study to map deception across the entire lifespan. Specifically, we investigated age-related difference in lying proficiency and lying frequency. A large community sample (n = 1005) aged between 6 and 77 were surveyed on their lying frequency, and performed a reaction-time (RT) based deception task to assess their lying proficiency. Consistent with the inverted U-shaped pattern of age-related changes in inhibitory control that we observed in a stop signal task, we found that lying proficiency improved during childhood (in accuracy, not RTs), excelled in young adulthood (in accuracy and RTs), and worsened throughout adulthood (in accuracy and RTs). Likewise, lying frequency increased in childhood, peaked in adolescence, and decreased during adulthood. In sum, we observed important age-related difference in deception that generally fit with the U-shaped pattern of age-related changes observed in inhibitory control. Theoretical and practical implications are discussed from a cognitive view of deception.

Impaired acquisition of goal-directed action in healthy aging

According to dual-system theories, instrumental learning is supported by dissociable goal-directed and habitual systems. Previous investigations of the dual-system balance in healthy aging have yielded mixed results. To further investigate this issue, we compared performance of young (17-24 years) and older (69-84 years) adults on an instrumental learning task. Following the initial learning phase, the behavioral autonomy of the motivational significance of the instrumental outcome was assessed with an outcome-devaluation test and slips-of-action test. The present study provides evidence for a disrupted dual-system balance in healthy aging, as reflected in reduced outcome-induced conflict during acquisition, as well as in impaired performance during the test stage, during which participants had to flexibly adjust their actions to changes in the current desirability of the behavioral outcome. These findings will be discussed in relation to previous aging studies into habitual and goal-directed control, as well as other cognitive impairments, challenges that older adults may face in everyday life, and to the neurobiological basis of the developmental pattern of goal-directed action across the lifespan.

The influence of executive functions on spatial biases varies during the lifespan

Many perceptual processes, such as language or face perception, are asymmetrically organised in the hemispheres already in childhood. These asymmetries induce behaviourally observable spatial biases in which the observer perceives stimuli in one of the hemispaces more efficiently or more frequently than in the other one. Another source for spatial biases is spatial attention which is also asymmetrically organised in the hemispheres. The bias induced by attention is directed towards the right side, which is clearly demonstrated by patients with neglect but also in lesser degree by healthy observers in cognitively loading situations. Recent findings indicate that children and older adults show stronger spatial biases than young adults. We discuss how the development of executive functions might contribute to the manifestation of spatial biases during the lifespan. We present a model in which the interaction between the asymmetrical perceptual processes, the age-related development of the lateralised spatial attention and the development of the executive functions influence spatial perceptual performance and in which the development and decline of the executive processes during the lifespan modify the spatial biases.

Functional Network Development During the First Year: Relative Sequence and Socioeconomic Correlations

The first postnatal year is characterized by the most dramatic functional network development of the human lifespan. Yet, the relative sequence of the maturation of different networks and the impact of socioeconomic status (SES) on their development during this critical period remains poorly characterized. Leveraging a large, normally developing infant sample with multiple longitudinal resting-state functional magnetic resonance imaging scans during the first year (N = 65, scanned every 3 months), we aimed to delineate the relative maturation sequence of 9 key brain functional networks and examine their SES correlations. Our results revealed a maturation sequence from primary sensorimotor/auditory to visual to attention/default-mode, and finally to executive control networks. Network-specific critical growth periods were also identified. Finally, marginally significant positive SES-brain correlations were observed at 6 months of age for both the sensorimotor and default-mode networks, indicating interesting SES effects on functional brain maturation. To the best of our knowledge, this is the first study delineating detailed longitudinal growth trajectories of all major functional networks during the first year of life and their SES correlations. Insights from this study not only improve our understanding of early brain development, but may also inform the critical periods for SES expression during infancy.

Superior longitudinal fasciculus and language functioning in healthy aging

Structural deterioration of brain tissue in older adults is thought to be responsible for the majority of age-related cognitive decline. Disruption of widespread cortical networks due to a loss of axonal integrity may also play an important role. Research examining correlations between structural change and functional decline has focused heavily on working memory, processing speed, and executive processes while other aspects of cognition, such as language functioning, have received less attention. The current study aimed to determine whether age-related changes in the superior longitudinal fasciculus (SLF), are responsible for the deterioration in language functioning associated with age. Subjects included 112 right-handed volunteers (ages 19-76). For each subject, the SLF of the left hemisphere was reconstructed from diffusion tensor images (DTI). Mean fractional anisotropy (FA) values were extracted from parietal (SLFp) and temporal (SLFt) bundles. Language functioning was measured using the Peabody Picture Vocabulary Test (PPVT), Boston Naming Test (BNT), Controlled Oral Word Association Test (COWAT), and Semantic Fluency Test (SFT). Regression analyses revealed that males and females showed a different pattern of decline in FA across adulthood. For males, greater SLFt FA was significantly associated with increased COWAT performance, and there was a positive relationship between both age and SLFp FA with BNT scores. In females, greater SLFp FA was related to lower COWAT performance. Taken together, the results suggest that white matter integrity of the SLF follows a different pattern of decline in adulthood for males and females, and this decline differentially affects language functioning.

Gaining control: changing relations between executive control and processing speed and their relevance for mathematics achievement over course of the preschool period

Early executive control (EC) predicts a range of academic outcomes and shows particularly strong associations with children's mathematics achievement. Nonetheless, a major challenge for EC research lies in distinguishing EC from related cognitive constructs that also are linked to achievement outcomes. Developmental cascade models suggest that children's information processing speed is a driving mechanism in cognitive development that supports gains in working memory, inhibitory control and associated cognitive abilities. Accordingly, individual differences in early executive task performance and their relation to mathematics may reflect, at least in part, underlying variation in children's processing speed. The aims of this study were to: (1) examine the degree of overlap between EC and processing speed at different preschool age points; and (2) determine whether EC uniquely predicts children's mathematics achievement after accounting for individual differences in processing speed. As part of a longitudinal, cohort-sequential study, 388 children (50% boys; 44% from low income households) completed the same battery of EC tasks at ages 3, 3.75, 4.5, and 5.25 years. Several of the tasks incorporated baseline speeded naming conditions with minimal EC demands. Multidimensional latent models were used to isolate the variance in executive task performance that did not overlap with baseline processing speed, covarying for child language proficiency. Models for separate age points showed that, while EC did not form a coherent latent factor independent of processing speed at age 3 years, it did emerge as a distinct factor by age 5.25. Although EC at age 3 showed no distinct relation with mathematics achievement independent of processing speed, EC at ages 3.75, 4.5, and 5.25 showed independent, prospective links with mathematics achievement. Findings suggest that EC and processing speed are tightly intertwined in early childhood. As EC becomes progressively decoupled from processing speed with age, it begins to take on unique, discriminative importance for children's mathematics achievement.

Effects of normal aging and SCN1A risk-gene expression on brain metabolites: evidence for an association between SCN1A and myo-inositol

Previously reported MRS findings in the aging brain include lower N-acetylaspartate (NAA) and higher myo-inositol (mI), total creatine (Cr) and choline-containing compound (Cho) concentrations. Alterations in the sodium channel voltage gated type I, alpha subunit SCN1A variant rs10930201 have been reported to be associated with several neurological disorders with cognitive deficits. MRS studies in SCN1A-related diseases have reported striking differences in the mI concentrations between patients and controls. In a study on 'healthy aging', we investigated metabolite spectra in a sample of 83 healthy volunteers and determined their age dependence. We also investigated a potential link between SCN1A and mI. We observed a significantly negative association of NAA (p = 0.004) and significantly positive associations of mI (p ≤ 0.001), Cr (p ≤ 0.001) and Cho (p = 0.034) with age in frontal white matter. The linear association of Cho ends at the age of about 50 years and is followed by an inverted 'U'-shaped curve. Further, mI was higher in C allele carriers of the SCN1A variant rs10930201. Our results corroborated the age-related changes in metabolite concentrations, and found evidence for a link between SCN1A and frontal white matter mI in healthy subjects.

Task difficulty and response complexity modulate affective priming by emotional facial expressions

In this study we used an affective priming task to address the issue of whether the processing of emotional facial expressions occurs automatically independent of attention or attentional resources. Participants had to attend to the emotion expression of the prime face, or to a nonemotional feature of the prime face, the glasses. When participants attended to glasses (emotion unattended), they had to report whether the face wore glasses or not (the glasses easy condition) or whether the glasses were rounded or squared (the shape difficult condition). Affective priming, measured on valence decisions on target words, was mainly defined as interference from incongruent rather than facilitation from congruent trials. Significant priming effects were observed just in the emotion and glasses tasks but not in the shape task. When the key-response mapping increased in complexity, taxing working memory load, affective priming effects were reduced equally for the three types of tasks. Thus, attentional load and working memory load affected additively to the observed reduction in affective priming. These results cast some doubts on the automaticity of processing emotional facial expressions.

Executive deficits in early onset bipolar disorder versus ADHD: impact of processing speed and lifetime psychosis

Executive deficits are reported in both early onset bipolar disorder (BD) and attention-deficit hyperactivity disorder (ADHD), and controversies regarding comorbidity and symptom overlap have complicated the research on executive function in BD. Reports of the negative impact of executive difficulties on academic functioning indicate a need for a greater focus on executive difficulties in early onset psychiatric disorders. Executive function and processing speed in youths with BD (n = 4), ADHD (n = 26) and BD + ADHD (n = 13) were compared with controls (n = 69). All clinical groups demonstrated executive impairment. The combined group was most impaired. There were no significant differences between the groups. Executive deficit in the BD group was associated with a history of psychotic symptoms. The BD-nonpsychotic group was impaired only with regard to processing speed. Processing speed adjustment improved working memory and normalized interference control in both BD and ADHD.

CONCLUSION

executive deficits in BD may be determined by a history of psychotic symptoms rather than by comorbid ADHD. Some aspects of executive problems appear speed-related.

A review of intentional and cognitive control in autism

Different clinical studies have provided empirical evidence for impairments in cognitive control in individuals with autism spectrum disorders (ASD). The challenge arises, however, when trying to specify the neurocognitive mechanisms behind the reported observations of deviant patterns of goal-directed behavior in ASD. Studies trying to test specific assumptions by applying designs that are based on a more controlled experimental conditions often fail in providing strong evidence for an impairment in specific cognitive functions. In this review, we summarize and critically reflect on behavioral findings and their theoretical explanations regarding cognitive control processing in autism, also from a developmental perspective. The specific focus of this review is the recent evidence of deficits in intentional control – a specific subset of cognitive control processes that biases the choice of our behavioral goals – coming from different research fields. We relate this evidence to the cognitive rigidity observed in ASD and argue that individuals with ASD experience problems at the intentional level rather than at the level of implementation of intentions. Both these processes are related to cognitive control mechanisms but in different ways. Finally, we discuss new directions in studying cognitive control in ASD and how these relate to adaptive cognition.

Online games training aging brains: limited transfer to cognitive control functions

The prevalence of age-related cognitive decline will increase due to graying of the global population. The goal of the present study was to test whether playing online cognitive training games can improve cognitive control (CC) in healthy older adults. Fifty-four older adults (age 60–77) played five different cognitive training games online for 30 min a day over a period of seven weeks (game group). Another group of 20 older adults (age 61–73) instead answered quiz questions about documentaries online (documentary group). Transfer was assessed by means of a cognitive test battery administered before and after the intervention. The test battery included measures of working memory updating, set shifting, response inhibition, attention, and inductive reasoning. Compared with the documentary group, the game group showed larger improvement of inhibition (Stop-Signal task) and inductive reasoning (Raven-SPM), whereas the documentary group showed more improvement in selective attention (UFoV-3). These effects qualify as transfer effects, because response inhibition, inductive reasoning and selective attention were not targeted by the interventions. However, because seven other indicators of CC did not show benefits of game training and some of those that did suffered from potential baseline differences, the study as a whole provides only modest support for the potential of videogame training to improve CC in healthy older adults.

Extension of the Contingency Naming Test to adult assessment: psychometric analysis in a college student sample

The Contingency Naming Test (CNT; Taylor, Albo, Phebus, Sachs, & Bierl, 1987) was initially designed to assess aspects of executive functioning, such as processing speed and response inhibition, in children. The measure has shown initial utility in identifying differences in executive function among child clinical groups; however, there is an absence of adequate psychometric data for use with adults. The current study expanded psychometric data upward for use with a college student sample and explored the measure's test-retest reliability and factor structure. Performance in the adult sample showed continued improvement above child norms, consistent with theories of executive function development. Exploratory factor analysis showed that the CNT is most closely related to measures of processing speed, as well as elements of response inhibition within the latter trials. Overall, results from the current study provide added support for the utility of the CNT as a measure of executive functioning in young adults. However, more research is needed to determine patterns of performance among adult clinical groups, as well as to better understand how performance patterns may change in a broader age range, including middle and older adulthood.

Movement skills of younger versus older adults with and without Down syndrome

Adults with Down syndrome (DS) are often physically inactive, which may accelerate the onset of disease and aging symptoms. Eight older persons with DS (aged 54-61), and 10 younger persons with DS (aged 26-35) living in a residential care center were examined. Eighteen age- and gender-matched individuals without DS served as control groups. Sensory-motor tasks and Posture Scale Analyzer (PSA) were used to examine coordination and standing stability. The isokinetic muscle strength test was used for muscle strength investigation. The functional performance, coordination, and leg muscle strength of the older adults with DS were more impaired than both the younger DS and the control groups. The older DS group showed lower sway rate and more symmetrical weight-bearing distribution during quiet standing than both the younger DS and the control groups. Our observations may have significant implications for understanding movement dysfunction in older adults with DS.

Mapping the development of response inhibition in young children using a modified day-night task

Response inhibition was examined in 40 children 3½ to 8 years of age using a modified day-night task. Performance in a neutral condition explained variance in congruent and incongruent conditions, indicating that age-related improvements in these latter conditions were partly mediated by working memory and processing speed. After controlling for neutral performance, age did not explain variance in congruent performance but explained variance in incongruent performance. These findings indicate that the associative strength between pictures and labels used in the task is age invariant and that older children are better than younger children at inhibiting responses to these associations.

Differential contribution of cognitive and psychomotor functions to the age-related slowing of speech production

Healthy elderly adults are slower to initiate and produce speech. However, the sources of the slowing remain poorly understood. The present study evaluates to which extent psychomotor and cognitive changes influence age-related slowing in speech generation. Four verbal tasks varying in degree of difficulty and cognitive demands were used to evaluate 30 young and 30 healthy elderly. Speed of word production was measured by reaction times and pronunciation durations. Stroop test and Digits backwards were used as cognitive predictors while the Purdue Pegboard and Finger Tapping were used as psychomotor predictors. The relative contribution of cognitive and psychomotor functioning was evaluated by hierarchical regression analyses and based on the processing speed hypothesis. Results showed that Vocabulary and psychomotor execution significantly explained a portion of the variance in RTs depending on type of verbal task. These variables explained 36% of the total variance in reading, 26% in naming, 31% in phonemic fluency and 47% in semantic fluency. Also, Vocabulary and psychomotor functions strongly predicted pronunciation speed. Conversely, tests related to executive functions and working memory were not significant predictors. These data demonstrate the importance of the interplay between Vocabulary and psychomotor decline on speed of language production among healthy elderly adults.

Longitudinal attentional engagement rescues mice from age-related cognitive declines and cognitive inflexibility

Learning, attentional, and perseverative deficits are characteristic of cognitive aging. In this study, genetically diverse CD-1 mice underwent longitudinal training in a task asserted to tax working memory capacity and its dependence on selective attention. Beginning at 3 mo of age, animals were trained for 12 d to perform in a dual radial-arm maze task that required the mice to remember and operate on two sets of overlapping guidance (spatial) cues. As previously reported, this training resulted in an immediate (at 4 mo of age) improvement in the animals' aggregate performance across a battery of five learning tasks. Subsequently, these animals received an additional 3 d of working memory training at 3-wk intervals for 15 mo (totaling 66 training sessions), and at 18 mo of age were assessed on a selective attention task, a second set of learning tasks, and variations of those tasks that required the animals to modify the previously learned response. Both attentional and learning abilities (on passive avoidance, active avoidance, and reinforced alternation tasks) were impaired in aged animals that had not received working memory training. Likewise, these aged animals exhibited consistent deficits when required to modify a previously instantiated learned response (in reinforced alternation, active avoidance, and spatial water maze). In contrast, these attentional, learning, and perseverative deficits were attenuated in aged animals that had undergone lifelong working memory exercise. These results suggest that general impairments of learning, attention, and cognitive flexibility may be mitigated by a cognitive exercise regimen that requires chronic attentional engagement.

Preparatory processes and compensatory effort in older and younger participants in a driving-like dual task

OBJECTIVE

The nature of increased-age-related dual-task interference was examined during a driving-like dual task in the laboratory.

BACKGROUND

Previous research revealed age-related deficits in dual tasks especially when cognitive and motor demands are involved. The specific contributions of sensory input, working memory demands, and/or coordination of motor responses to dual-task interference are not clear and should be clarified in the present study.

METHOD

Younger and older participants performed a driving-like tracking task and a visually cued attention task within a dual task. Behavioral and electrophysiological data were recorded during task performance.

RESULTS

Overall tracking performance was lower for the older versus younger participants. This age-related decline was particularly pronounced in the time interval after the stimulus when the attention task demanded a motor response. In contrast, older participants tracked relatively better than the younger participants in the time interval preceding the stimulus. In the attention task, the older versus younger participants showed increased responses times and rates of false alarms and misses, suggesting a deficit in retaining the context in the cue-stimulus interval. The electroencephalogram data suggest that the older participants invested more resources than the younger participants in dual-task management during the cue-stimulus interval.

CONCLUSION

Evidence was found for increased motor interference and a deficient context processing as well as for an increased investment of processing resources in the older compared with the younger group.

APPLICATION

The results suggest that in-vehicle information systems for older drivers should be designed to support cue maintenance and that simultaneous motor demands should not be required.

A latent variables examination of processing speed, response inhibition, and working memory during typical development

This study addressed three related aims: (a) to replicate and extend previous work regarding the nonunitary nature of processing speed, response inhibition, and working memory during development; (b) to quantify the rate at which processing speed, response inhibition, and working memory develop and the extent to which the development of these latter abilities reflect general changes in processing speed; and (c) to evaluate whether commonly used tasks of processing speed, response inhibition, and working memory are valid and reliable when used with a developmentally diverse group. To address these aims, a latent variables approach was used to analyze data from 147 participants 6-24years of age. Results showed that processing speed, response inhibition, and working memory were separable abilities and that the extent of this separability was stable across the age range of participants. All three constructs improved as a function of age; however, only the effect of age on working memory remained significant after processing speed was controlled. The psychometric properties of tasks used to assess the constructs were age invariant, thereby validating their use in studies of executive development.

The development of inhibitory control: an averaged and single-trial Lateralized Readiness Potential study

Inhibitory control (IC) is an important contributor to educational performance, and undergoes rapid development in childhood. Age-related changes in IC were assessed using an in-depth analysis of reaction time, the Lateralized Readiness Potential (LRP), and other event-related potential (ERP) measures to control for speed of processing. Five-year-olds, 8-year-olds and adults completed an adapted Stroop task. Both reaction time and ERP results suggest that IC does develop in this age range, over and above changes in speed of processing. The LRP identified two processes that contribute to IC. These processes develop at different rates--an early process, involving how the conflict is initially responded to is mature by age 5, while a later process, involving how the conflict is overcome is still developing after 8 years of age. We propose that these early and late processes reflect interference suppression and response inhibition, respectively. Further, a single-trial analysis of the LRP in the incongruent condition provides evidence that the LRP is consistent across trials and functionally similar in each age group. These results corroborate previous findings regarding the development of IC, and present a new and useful tool for assessing IC across development.

Understanding genetic, neurophysiological, and experiential influences on the development of executive functioning: the need for developmental models

Flexibility is a cornerstone of adaptive behavior and is made possible by a family of processes referred to collectively as executive functions. Executive functions vary in efficacy from individual to individual and also across developmental time. Infants and young children, for example, have difficulty flexibly adapting their behavior, and often repeat actions that are no longer appropriate. And although older children do not typically make such striking errors, they have more difficulty exercising control than adolescents and adults. Such developmental variability parallels (at least in some respects) inter-individual variability in executive functions. Individuals who suffer damage or dysfunction in regions of the prefrontal cortex, for example, often experience difficulty in flexibly adapting their behavior to changes in context. As well, genetic differences between individuals are strongly associated with differences in executive control. Parallels between developmental and inter-individual variability suggest hypotheses about possible mechanisms underlying the development of executive functions but carry risks when interpreted improperly. Overcoming these pitfalls will require mechanistic characterizations of executive functioning that are more deeply rooted in developmental principles. Copyright © 2010 John Wiley & Sons, Ltd. For further resources related to this article, please visit the WIREs website.

Cognitive screening for children and adolescents: general limits or ceiling effects?

Cognitive screening tools designed for children can also be used with adolescents. However, early studies suggest that scores can approach a maximum at about age 10 or 11 years. The initial hypothesis was this apparent ''ceiling effect'' is due to limits in the materials, where items can be insufficiently challenging for some adolescents. The alternative hypothesis is that general cognitive screening has a true limit by early adolescence. Participants (N = 85) were 10 to 15-year-old girls and boys, with a database (N = 1249) of 4 to 12-year-old children. The School-Years Screening Test for the Evaluation of Mental Status (SYSTEMS) cognitive screening was extended by more difficult items. Results show that scores increase rapidly for young children and tend toward a maximum in early adolescence. This characteristic asymptotic curve explained a substantial proportion of the variance. We can conclude that, although specific functions continue to develop, there is an upper limit in early adolescence for such general cognitive functioning. The findings support cognitive screening across a broad age range and suggest worthwhile research and clinical applications.

Modulation of decision-making in a gambling task in older adults with transcranial direct current stimulation

Cognitive performance usually declines in older adults as a result of neurodegenerative processes. One of the cognitive domains usually affected is decision-making. Based on our recent findings suggesting that non-invasive brain stimulation can improve decision-making in young participants, we studied whether bifrontal transcranial direct current stimulation (tDCS) applied over the right and left prefrontal cortex of older adult subjects can change balance of risky and safe responses as it can in younger individuals. Twenty-eight subjects (age range from 50 to 85 years) performed a gambling risk task while receiving either anodal tDCS over the right and cathodal tDCS over the left dorsolateral prefrontal cortex (DLPFC), anodal tDCS over the left with cathodal tDCS over the right DLPFC, or sham stimulation. Our main finding was a significant group effect showing that participants receiving left anodal/right cathodal stimulation chose more often high-risk prospects as compared with participants receiving sham or those receiving right anodal/left cathodal stimulation. This result is contrary to previous findings in young subjects, suggesting that modulation of cortical activity in young and elderly results in opposite behavioral effects; thus supporting fundamental changes in cognitive processing in the elderly.

Some guidelines for structural equation modelling in cognitive neuroscience: the case of Charlton et al.'s study on white matter integrity and cognitive ageing

Charlton et al. (2008) (Charlton, R.A., Landua, S., Schiavone, F., Barrick, T.R., Clark, C.A., Markus, H.S., Morris, R.G.A., 2008. Structural equation modelling investigation of age-related variance in executive function and DTI-measured white matter change. Neurobiol. Aging 29, 1547-1555) presented a model that suggests a specific age-related effect of white matter integrity on working memory. We illustrate potential pitfalls of structural equation modelling by criticizing their model for (a) its neglect of latent variables, (b) its complexity, (c) its questionable causal assumptions, (d) the use of empirical model reduction, (e) the mix-up of theoretical perspectives, and (f) the failure to compare alternative models. We show that a more parsimonious model, based solely on the well-established general factor of cognitive ability, fits their data at least as well. Importantly, when modelled this way there is no support for a role of white matter integrity in cognitive aging in this sample, indicating that their conclusion is strongly dependent on how the data are analysed. We suggest that evidence from more conclusive study designs is needed.

CROSS-CULTURAL ASSESSMENT OF NEUROPSYCHOLOGICAL PERFORMANCE AND ELECTRICAL BRAIN FUNCTION MEASURES: ADDITIONAL VALIDATION OF AN INTERNATIONAL BRAIN DATABASE

Previous studies have revealed significant differences in performance on nonlanguage dependent cognitive tests across international settings among younger individuals, with less pronounced differences evident among older individuals (>54 years of age). The present study examined a broad range of cognitive performance as well as electrophysiological indices of brain function in a multisite and international context. A total of 200 individuals in the United States, 233 individuals in Europe, and 829 individuals in Australia were administered a standardized computerized neuropsychological battery, and complementary electroencephalogram (EEG) recordings were completed. Results revealed no significant differences in cognitive function or electrophysiology across the three continents. Similarly, although there was a main effect for age, the interaction between age and continent was not significant in any of the omnibus analyses. These findings indicate a high degree of similarity in neurocognitive and electrophysiological function among individuals residing in developed Western cultures, consistent with a traitlike status and the high heritability of the EEG.

A structural equation modeling investigation of age-related variance in executive function and DTI measured white matter damage

Cognitive changes in normal aging have been explained by the frontal-executive hypothesis, but the assumptions made by this hypothesis concerning the neurobiological causes are still a matter of debate. Executive functions (EF) may activate neural networks that include disparate grey matter regions, and rely on the integrity of white matter connections. In 118 adults (50-90 years old) from the GENIE study, white matter integrity was measured using diffusion tensor imaging, and information processing speed, fluid intelligence and EF were assessed. A theory-driven structural equation model was developed to test associations between variables. The model was revised, removing non-significant paths. The adjusted model explained well the covariance in our data; and suggested that the reduction in white matter integrity associated with age directly affected only working memory. Fluid intelligence was mediated by all measured cognitive variables. The results suggest that white matter integrity may be particularly important for abilities activating complex neural networks, as occurs in working memory. Integration of the information processing speed and frontal-executive hypotheses may provide important information regarding common, unique, and mediating factors in cognitive aging.

Perceptual-motor coordination in persons with mild intellectual disability

BACKGROUND

There is limited experimental evidence to support the view that individuals with intellectual disabilities (ID) have a deficit in motor control. This work is a first attempt to evaluate their motor coordination.

PURPOSE

The study assessed the relationship between cognitive ability and sensorimotor integration. The clinical hypothesis is that adults with ID fall below non-ID adults in motor skills that involve hand-eye coordination.

METHOD

A group of 42 adults with ID (ID group) was compared to 48 age-matched typical adults (TA) using a mixed experimental design ('Task' as the within-subjects factor and 'Group' as the between-subjects factor). Participants performed the following tests twice: Box-and-Blocks, 25-Grooved-Pegboard, Stick Catching and overhead Beanbag-Throw. Pearson correlations and ANOVAs were used to test the hypothesis (p < or = 0.05).

RESULTS

As expected, TA outperformed the ID group in all tests regardless of the hand used during for the assessment. However, TA individuals scored significantly better with one hand (i.e., the preferred and dominant hand) as opposed to persons with ID, who exhibited no hand preference. Test-retest correlations among the first and second assessment scores yielded moderate-strong coefficients, depending on the type of test (Box-and-Blocks = 0.92 and 0.96, 25-Grooved-Pegboard = 0.69 and 0.83, Stick-Catching = 0.88 and 0.94, Beanbag-Throw = 0.58 and 0.91 for ID and TA, respectively).

DISCUSSION

Difficulties in the integration of perceptual information into motor action may result in inadequate solutions to daily motor problems. As it stems from our results, intellectual disability relates to inability to integrate visual inputs and hand movements. In people with mild ID such inability is observed using both hands (i.e., they show no hand preferences). Poor perceptual-motor coordination might have a functional significance in that it may lead to exclusion from vocational and recreational activities, and a decreasing competence of ADL. Assessing coordination in adults with ID may contribute to understanding the nature of the ID condition and may encourage an early rehabilitation.