Higher Working Memory Performance Research Articles

Variations in Theta/Beta Ratio and Cognitive Performance in Subpopulations of Subjects with ADHD Symptoms: Towards Neuropsychological Profiling for Patient Subgrouping.

ADHD is a neurodevelopmental disorder appearing in childhood but remaining in many cases in adults. There are both pharmacological and non-pharmacological approaches to treating ADHD, but they do not have the same efficacy in all subjects. Better knowledge of the neurophysiological basis of this disorder will allow for the design of more effective treatments. Studies performing qEEG analysis in children suggest the existence of subgroups of ADHD patients with different neurophysiological traits. There are fewer studies in adults, who might have undergone plastic changes allowing them to cope with ADHD symptoms along with brain maturation. Herein, we study cognitive performance and the theta/beta ratio in young adults with ADHD symptoms. We found that subjects with ADHD symptoms and low working memory performance (n = 30) present higher theta/beta ratios than controls (n = 40) at O2 and T6 in the eyes-closed condition, as well as a tendency toward a higher theta/beta ratio at O1 and Cz. Subjects with ADHD and high working memory performance (n = 50) do not differ from the controls in their theta/beta ratios at any derivation. Our results suggest that neuropsychological profiling could be useful for patient subgrouping. Further research will allow for the distinction of neuropsychological profiles and their neurophysiological correlates, leading to a better classification of ADHD subtypes, thus improving treatment selection.

Effects of nature on restorative and cognitive benefits in indoor environment

This study investigates the effects of natural exposure in an indoor environment on restorative quality and cognitive ability. Thirty participants were shown nature at three different indoor sites: baseline, indoor (some vegetation), and semi-indoor (a large amount of vegetation and view to sky) for five minutes. After viewing, they completed an assessment of restoration and a cognitive task, and their electroencephalography (EEG) was recorded. Compared to the baseline, the sites with nature resulted in restorative (higher perceived restoration scores) and cognitive (higher working memory performance and lower delta-to-theta ratio (DTR), delta-to-alpha ratio (DAR), theta-to-beta ratio (TBR), and alpha-to-beta ratio (ABR) responses) benefits. These findings further our understanding of the effects of exposure to nature on restorative and cognitive benefits in an indoor environment, and help to build guidance for future research on the effects of nature indoors and designing restorative- and cognitive-enhancing indoor spaces.

BEHAVIORAL AND SOCIAL IMPACTS ON DAILY VARIABILITY IN HEALTH AND FUNCTIONING IN OLD AND VERY OLD AGE

Abstract In recent years, research has shown that people experience substantial variability in domains such as cognition, health, or social interactions from day-to-day or even moment-to-moment. This variability carries relevant information above and beyond an individual’s mean levels of functioning, revealing, for instance, potential risk factors for healthy aging. Thus, aging research increasingly examined such variations in older adults’ daily lives, aiming to further the understanding of aging processes with insights into short- and long-term predictors of daily health and functioning. In this symposium, we introduce research using repeated daily life assessments from older participants to elucidate behavioral and social impacts on variations in working memory performance, pain and self-rated health, as well as social interaction quality. Luo et al. show that diverse daily activities were linked with higher working memory performance one the same day. Regarding long-term prediction, Schilling et al. found that patterns of alcohol consumption across two decades were only weakly predictive of subsequent short-term variability in daily working memory performance. Turning from cognitive functioning to health, Lücke et al. observed bidirectional links of variations in daily sleep quality with variations in daily pain and health perceptions across several days. Finally, Hülür et al. addressed the role of communication technologies for older persons’ social interactions and found that daily social interaction quality differs with the interaction modalities. Scott Hofer will discuss the implications of the presented findings for our understanding of variability in everyday functioning in old age, considering challenges and opportunities for future research in this field.

Fine motor skill automatization and working memory in children with and without potential fine motor impairments: An explorative study.

The present study explored fine motor skill automatization and working memory in kindergarten children with and without potential fine motor impairments. For both groups, lower performance was expected in a cognitive-motor dual-task compared to single-tasks. Children with potential fine motor impairments were expected to show higher dual-task costs (indicating lower automatization) and lower working memory performance compared to children without potential fine motor impairments. The sample included 18 kindergarten children (mean age M=67.17months, SD=4.34months) with potential fine motor impairments (scoring at or below the 9th percentile of the manual dexterity scale of the Movement ABC-2; Petermann, 2011) and 36 children scoring above the 9th percentile of the manual dexterity scale of the Movement ABC-2 (mean age M=67.56months; SD=3.74). All children completed a fine motor task (trail drawing) and a working memory task (digit span backwards) in single- and dual-task conditions. Results showed an overall lower cognitive but not fine motor performance in the dual-task condition compared to the single-task condition. Overall, the group scoring above the 9th percentile showed a lower error-to-length ratio and higher working memory performance than the group with potential fine motor impairments. The dual-task costs did not differ between the groups. Although the potential fine motor impaired children did not show an automatization deficit, they might be at risk of academic problems due to their lower fine motor and working memory performance. Implications for school and interventions are discussed.

Multimodal Correlates of Cannabis Use among U.S. Veterans with Bipolar Disorder: An Integrated Study of Clinical, Cognitive, and Functional Outcomes

Objective: Cannabis use (CU) is common among persons with bipolar disorder (BD). Evidence suggests that CU is associated with poorer outcomes among persons with BD; however, these findings remain inconsistent. The present exploratory study aims to examine clinical, functional, and cognitive correlates of CU among persons with BD. Methods: U.S. veterans with BD type I who participated in a large-scale, nationwide study were categorized into four groups: current CU, past CU, past other drug use, and no drug use. Bivariate analyses, univariate analyses of covariance, and Levene’s Test for Equality of Variance were used to compare groups on clinical, cognitive, and functional measures. Results: Of 254 (84.6% male) veterans with BD type I included in the analyses, 13 (5.1%) had current CU, 37 (14.5%) past CU, 77 (30.3%) past other drug use, and 127 (50%) reported no drug use. BD with CU was associated with post-traumatic stress disorder (PTSD) and experiencing lifetime suicidal ideation. Notably, current CU was associated with higher working memory performance, compared to both past CU and no drug use. Likewise, current CU was associated with higher functional capacity, compared to past CU as well as no drug use. Conclusions: These findings contribute to the growing literature on the complex effects of cannabis on BD. As the commercialization and legalization of cannabis increases, further research in this area is warranted to quantify posed risks to this population, and thereby guide clinical decision-making.

Investigation of Working Memory Performances of Children with Low Early Mathematics Achievement

This study examined the working memory performance of children with low early mathematics achievement in comparison with their peers and analyzed the relationships between these skill areas. The distribution of children with low, average and high early mathematics achievement according to their working memory levels was also examined. The participants consisted of 100 kindergarten children with typical development and average and above-average intelligence. The Colored Progressive Matrices Test (CPM) was used to determine nonverbal intelligence levels, the Test of Early Mathematics Ability, Third Edition (TEMA-3) to evaluate early math skills and the Working Memory Scale (WMS) to determine working memory performances of the children. Children were divided into three groups of low, average and high achievement according to their early mathematics achievement assessed by the TEMA-3. It was found that the working memory performances of children with low, average and high achievement in early mathematics differed significantly. The working memory performance of children with low early mathematics achievement was significantly lower than their peers with average and high achievement. The results of the relationships between early math skills and working memory showed that early math skills and working memory components, except for visual short-term memory, were correlated to a small and medium degree. The distributions of working memory levels of the groups were examined and the results showed that children with low early mathematics achievement had low and average working memory performance, while children with high early mathematics achievement mostly had average and high working memory performance. However, none of the children with low early mathematics achievement showed high working memory performance. The results are discussed within the framework of the literature.

Deactivation of the attention-shifting ventromedial prefrontal cortex during the encoding and hold phases predicts working memory performance.

Recent neuroimaging studies have suggested that the deactivation of the ventromedial prefrontal cortex (VMPFC) works with the attention shifting area to facilitate the encoding of behaviorally relevant inputs. These findings have led to the notion that the deactivation of VMPFC substantially contributes to the cognitive control of emotions. Although VMPFC deactivation during working memory tasks is established, whether it contributes to performance in emotionally distracted working memory tasks remains unclear. This study aimed to investigate whether the magnitude of VMPFC deactivation predicts better performance in emotionally distracted working memory tasks. Twenty-nine female participants performed delayed-response working memory tasks with emotional distracters presented during the hold phase of working memory while undergoing functional MRI. A GLM and a paired t-test were used to observe brain responses to emotional distracters. The correlation between brain response and working memory performance was also computed to investigate brain areas that predict working memory performance in emotionally distracted tasks. Three trends in brain activity were strongly correlated with high working memory performance: (1) increased activity in cognitive control areas (dorsolateral prefrontal cortex), (2) lower activity in emotional reactivity areas (fusiform gyrus), and (3) deactivation of the attention shifting area, mainly VMPFC. In addition, all three trends correlated with high working memory performance during the hold phase of working memory, whereas only (2) and (3) correlated with high working memory performance during the encoding phase. These results provide further evidence of the functional importance of VMPFC and demonstrate that VMPFC deactivation is particularly important during the encoding and hold phases of working memory.

Development of cardiorespiratory fitness standards for working memory using receiver operating curves in 15-year-old adolescents

BackgroundWorking memory performance is associated with better academic achievements in children and adolescents, and it is positively related to CRF. However, what level of cardiorespiratory fitness (CRF) discriminates higher working memory performance is not known. The purpose of this study was to identify CRF thresholds linked to working memory in adolescents.MethodsData of 141 adolescents (53.2 % girls) were collected (14.9 years) from a cross-sectional study during the year 2019. CRF was assessed by the 20-m shuttle run test, and maximal oxygen uptake was calculated using the Mahar´s equation. Working memory was evaluated by the Corsi blocks test and performance was classified by percentiles. Receiver operating characteristic (ROC) curve analysis was used to identify CRF thresholds.ResultsThe ROC analysis indicated that CRF could be used to discriminate working memory in adolescents. CRF thresholds of ≥45.03 ml.kg− 1.min− 1for boys and ≥36.63 ml.kg− 1.min− 1for girls were found to be indicative of “normal” working memory performance.ConclusionsCRF could discriminate low and normal working memory performance in 14-16- year-old adolescents. These thresholds could allow for earlier identification and intervention of low working memory performance using CRF.

Working memory modulation using multifocal transcranial direct current stimulation in stable and decliner older adults

AbstractBackgroundThe combination of transcranial direct current stimulation (tDCS) with functional magnetic resonance imaging (fMRI) is able to provide original data about how brain change in aging. Furthermore, tDCS procedures might moderate age‐related brain functional changes associated to cognitive decline. In the present study, we aimed to investigate in which manner two multifocal tDCS procedures based on two distinct working memory (WM) patterns entail capability to modulate neural activity in older adults showing cognitive stability or decline.MethodTwo multifocal tDCS montages were designed to generate two distinct electric field distributions fitting either ‘compensatory’ or ‘maintenance’ fMRI patterns underlying high WM performance, described in a previous publication from our group (Fernández‐Cabello et al., Neurobiol Aging, 2016). A sham‐controlled crossover study was undertaken on three separate experimental sessions, where 24 healthy elders (mean age: 71.73±2.65 years, 14 females) performed a verbal N‐back task while fMRI data was acquired. During the fMRI acquisitions, tDCS was applied using ‘compensatory’, ‘maintenance’ or sham stimulation in a randomized counter‐balanced order. Each subject was retrospectively classified as showing WM stability (N=12) or decline (N=12) at baseline (i.e. during sham condition) based on the WM scores obtained 4 years before. We studied differences in fMRI between group’ trajectories and across the different tDCS montages.ResultThere was a significant time*group interaction, where the decliners evidenced a longitudinal progression marked by an over‐activation of non‐related WM areas. Focusing on the stimulation intervention, we identified a significant interaction group (stables vs. decliners) * condition (‘compensatory’ vs. sham). Regarding the specific effects for each group and montage, only in the decliner group, the ‘compensatory’ tDCS induced an activity reduction overlapping posterior cortical regions, whose longitudinal hyperactivation was characteristic of this group.ConclusionThe present results reinforce the notion that tDCS effects depend on the underlying age‐related functional organization and that these effects might be larger as more compromised is a system. Moreover, our findings are also in accordance with the hypothesis that tDCS is able to normalize functional patterns subtending cognitive decline in aging.

Prefrontal haemodynamics based classification of inter‐individual working memory difference

This Letter illustrates prefrontal haemodynamics as a neurovascular basis of inter-personal working memory differences. A functional near-infrared spectroscopy with sampling frequency ∼2 Hz is used to record the blood oxyhaemoglobin and deoxyhaemoglobin signals from 19 subjects engaged in working memory task of encoding and retrieval of ten symbol-meaning association learning. The individual difference in working memory performance is classified by supervised learning-based linear discriminant analysis and ensemble classifiers. Prior to the classification approach, individual performance is labelled as high, moderate and low on the basis of the performance index. The spontaneous haemodynamic activity and task-evoked responses are marked as background and foreground signals, respectively, which are scaled by means of stream-independent and stream-dependent models. The classifiers' performance shows that the stream-dependent model-based feature construction-classification improves classification accuracy to a major extent compared to the stream-independent model and no gain model. To understand the neurovascular basis of the inter-individual performance difference, diffused voxel plots are constructed. The voxel plots showed that concurrent activation of orbitofrontal and dorsolateral prefrontal cortex could have a possible association with persons' higher working memory performance.

Economical Assessment of Working Memory and Response Inhibition in ADHD Using a Combined n-back/Nogo Paradigm: An ERP Study

The development of cognitive interventions in attention-deficit/hyperactivity disorder (ADHD) often requires the assessment of multiple cognitive functions. However, experimental settings consisting of various tasks are particularly strenuous for patients and can thus result in poor data quality. For the economical assessment of working memory and response inhibition, this study aims to validate a combined n-back/nogo paradigm by comparing it to single task versions and to demonstrate its applicability for ADHD research. Twenty-five healthy individuals and 34 ADHD patients between 9 and 16 years participated in this event-related potential (ERP) study. Healthy controls underwent single task versions of a 2-back working memory task and a go/nogo response inhibition task as well as the introduced combined 2-back/nogo task. This combined task demonstrated a comparable ERP structure for working memory and response inhibition aspects as single task versions. Behaviorally, higher working memory performance during the combined paradigm indicated lower task difficulty, while high correlations between combined and single task versions still indicated valid working memory measures. For response inhibition performance, different task versions resulted in similar outcomes. The application of the combined n-back/nogo paradigm in ADHD patients revealed the expected working memory and response inhibition deficits, increased omission errors, reaction times, and standard deviation of reaction time, as well as diminished n-back P3 and nogo P3 amplitudes. We conclude that the combined n-back/nogo task is an effective paradigm for the economical assessment of working memory and response inhibition deficits in ADHD on a behavioral and neurophysiological level.

0119 The Role of Aging and Working Memory in Emotional-Long Term Memory Formation

Abstract Introduction It is widely accepted that “offline” processes during sleep contributes to memory. Working Memory (WM) capacity, which reflects “online” memory processing, is an important factor influencing cognitive functioning, which declines with age. In younger individuals, a positive association is reported between WM-capacity and declarative memory improvement. Methods We examined the relation between WM and long-term memory consolidation, among younger [N=105, 18-25yr] and older adults (N=119, 60-85yr). Subjects completed an OSPAN WM task, encoded a Word-Paired Association (WPA) task in the morning (Test1), and were tested on the WPA in the afternoon (Test2) after a 90-minute polysomnographically-recorded nap or wake. Half of the subjects were exposed to negatively valenced word-pairs (EWPA) while the other half were exposed to neutral word-pairs (NWPA). Subjects rated valence of the word-pairs at Test1 and Test2. We compared the four groups (young-EWPA, young-NWPA, old-EWPA and old-NWPA) on WM and WPA in both wake and sleep. Results In both wake and sleep, in the WPA, ageXword-condition interaction was found (p=.004). Post-hoc analysis revealed that in wake, younger-EWPA had higher performance (p=.03) than younger-NWPA, however, older-EWPA had lower performance (p=.03) than older-NWPA. Additionally, we found an ageXword-condition interaction whereby youngers showed no change in ratings, while older adults rated word-pairs more positively both in wake (p=.03) and sleep (p=.002) at Test 2. Youngers had higher WM performance (p=.007), also their WM performance was positively associated with WPA both for Neutral (p=.03) and Emotional (p=.01). WM and WPA among older adults was not related. In younger-EWPA, Stage2-sleep-minutes was positively associated to WPA improvement (p=.03) where this association was negative among older-EWPA (p=.02). In older-NWPA, Stage2-sleep-minutes was positively associated with WPA (p=.004). Conclusion Our findings indicate an association between WM and emotionally-salient memory formation that is modulated by age. Older adults, but not younger, showed the emotional bias previously reported. WM was higher in younger adults related to memory improvement. Stage2-sleep was related to memory improvement in both groups, but in opposite directions. In sum, the role of sleep in memory consolidation changes with aging and WM may play a role in this process. Support Fenn et al.,2012

Functional and structural correlates of working memory performance and stability in healthy older adults.

Despite the well-described deleterious effects of aging on cognition, some individuals are able to show stability. Here, we aimed to describe the functional and structural brain characteristics of older individuals, particularly focusing on those with stable working memory (WM) performance, as measured with a verbal N-back task across a 2-year follow-up interval. Forty-seven subjects were categorized as stables or decliners based on their WM change. Stables were further subdivided into high performers (SHP) and low performers (SLP), based on their baseline scores. At both time points, magnetic resonance imaging (MRI) data were acquired, including task-based functional MRI (fMRI) and structural T1-MRI. Although there was no significant interaction between overall stables and decliners as regards fMRI patterns, decliners exhibited over-activation in the right superior parietal lobule at follow-up as compared to baseline, while SHP showed reduced the activity in this region. Further, at follow-up, decliners exhibited more activity than SHP but in left temporo-parietal cortex and posterior cingulate (i.e., non-task-related areas). Also, at the cross-sectional level, SLP showed lower activity than SHP at both time points and less activity than decliners at follow-up. Concerning brain structure, a generalized significant cortical thinning over time was identified for the whole sample. Notwithstanding, the decliners evidenced a greater rate of atrophy comprising the posterior middle and inferior temporal gyrus as compared to the stable group. Overall, fMRI data suggest unsuccessful compensation in the case of decliners, shown as increases in functional recruitment during the task in the context of a loss in WM performance and brain atrophy. On the other hand, among older individuals with WM cognitive stability, differences in baseline performance might determine dissimilar fMRI trajectories. In this vein, the findings in the SHP subgroup support the brain maintenance hypothesis, suggesting that stable and high WM performance in aging is sustained by functional efficiency and maintained brain structure rather than compensatory changes.

Development of dopaminergic genetic associations with visuospatial, verbal and social working memory.

Dopamine transmission in the prefrontal cortex (PFC) supports working memory (WM), the temporary holding, processing and manipulation of information in one's mind. The gene coding the catechol‐O‐methyltransferase (COMT) enzyme, which degrades dopamine, in particular in the PFC, has a common single nucleotide polymorphism leading to two versions of the COMT enzyme which vary in their enzymatic activity. The methionine (Met) allele has been associated with higher WM performance and lower activation of the PFC in executive function tasks than the valine (Val) allele. In a previous study, COMT genotype was associated with performance on verbal and visuospatial WM tasks in adults, as well as with performance on a novel social WM paradigm that requires participants to maintain and manipulate information about the traits of their friends or family over a delay. Here, data collected in children and adolescents (N = 202) were compared to data from the adult sample (N = 131) to investigate possible age differences in genetic associations. Our results replicate and extend previous work showing that the pattern of superior WM performance observed in Met/Met adults emerges during development. These findings are consistent with a decrease in prefrontal dopamine levels during adolescence. Developmentally moderated genetic effects were observed for both visuospatial and social WM, even when controlling for non‐social WM performance, suggesting that the maintenance and manipulation of social information may also recruit the dopamine neurotransmitter system. These findings show that development should be considered when trying to understand the impact of genetic polymorphisms on cognitive function.

Transcranial direct current stimulation over the right and left VLPFC leads to differential effects on working and episodic memory

Previous research suggests that the left VLPFC is involved in working memory, whereas right VLPFC is involved with subsequent episodic memory. High-Definition Transcranial Direct Current Stimulation (HD-tDCS) was used to test whether excitation of the left or right VLPFC would show differential effects of negative and neutral stimuli on working memory and episodic memory tasks. While receiving HD-tDCS over the left or right VLPFC or sham stimulation, participants completed a working memory task with negative and neutral distractors followed by a surprise recognition test for the distractors. HD-tDCS over the left VLPFC led to improved working memory performance compared to sham for both negative and neutral distractors. However, for trials that were subsequently remembered, a greater proportion of working memory trials were correct for both the right and left VLPFC group compared to the sham group, for both negative and neutral distractors. Whereas the results from the left VLPFC group can be attributed to overall higher working memory performance, findings from the right VLPFC suggest a role of the right VLPFC in coping with distracting stimuli. Taken together, these results indicate causal roles for the left VLPFC in working memory and the right VLPFC in working memory and episodic memory.

The influence of working memory performance on event-related potentials in young and older adults

ABSTRACTVariations in brain activation may lead to individual differences in working memory (WM) performance. Such differences may account for contradictory findings in the literature relating to age-related changes in neural activation during WM tasks. In the present study, 39 young adults (aged 18–30) and 34 older adults (aged 65+) completed an n-back task while their electroencephalography, accuracy, and reaction time was recorded. They were then categorized as high or low performers. High performers had larger P3b and parietal P200 amplitudes and smaller parietal N200 amplitudes than low performers. High-performing older adults exhibited larger parietal P200 amplitudes than low-performing older adults, and similar P3bs to young adults during the 2-back. Low-performing older adults, in contrast, exhibited smaller parietal P3bs than young adults during the 2-back. These findings suggest that brain activity during a WM task is influenced by individual differences in performance level. Moreover, some older adults can maintain high WM performance and capacity through recruitment of additional brain regions.

Do Learned Alarm Sounds Interfere With Working Memory?

To assess whether identifying (or ignoring) learned alarm sounds interferes with performance on a task involving working memory. A number of researchers have suggested that auditory alarms could interfere with working memory in complex task environments, and this could serve as a caution against their use. Changing auditory information has been shown to interfere with serial recall, even when the auditory information is to be ignored. However, previous researchers have not examined well-learned patterns, such as familiar alarms. One group of participants learned a set of alarms (either a melody, a rhythmic pulse, or a spoken nonword phrase) and subsequently undertook a digits-forward task in three conditions (no alarms, identify the alarm, or ignore the alarm). A comparison group undertook the baseline and ignore conditions but had no prior exposure to the alarms. All alarms interfered with serial recall when participants were asked to identify them; however, only the nonword phrase interfered with recall when ignored. Moreover, there was no difference between trained and untrained participants in terms of recall performance when ignoring the alarms, suggesting that previous training does not make alarms less ignorable. Identifying any alarm sound may interfere with immediate working memory; however, spoken alarms may interfere even when ignored. It is worth considering the importance of alarms in environments requiring high working memory performance and in particular avoiding spoken alarms in such environments.

Examining factors involved in stress-related working memory impairments: Independent or conditional effects?

A large and growing body of research demonstrates the impact of psychological stress on working memory. However, the typical study approach tests the effects of a single biological or psychological factor on changes in working memory. The current study attempted to move beyond the standard single-factor assessment by examining the impact of 2 possible factors in stress-related working memory impairments. To this end, 60 participants completed a working memory task before and after either a psychological stressor writing task or a control writing task and completed measures of both cortisol and mind wandering. We also included a measure of state anxiety to examine the direct and indirect effect on working memory. We found that mind wandering mediated the relationship between state anxiety and working memory at the baseline measurement. This indirect relationship was moderated by cortisol, such that the impact of mind wandering on working memory increased as cortisol levels increased. No overall working memory impairment was observed following the stress manipulation, but increases in state anxiety and mind wandering were observed. State anxiety and mind wandering independently mediated the relationship between change in working memory and threat perception. The indirect paths resulted in opposing effects on working memory. Combined, the findings from this study suggest that cortisol enhances the impact of mind wandering on working memory, that state anxiety may not always result in stress-related working memory impairments, and that high working memory performance can protect against mind wandering.

DRD2/ANKK1 polymorphism modulates the effect of ventral striatal activation on working memory performance.

Motivation is important for learning and cognition. Although dopaminergic (D2) transmission in the ventral striatum (VS) is associated with motivation, learning, and cognition are more strongly associated with function of the dorsal striatum, including activation in the caudate nucleus. A recent study found an interaction between intrinsic motivation and the DRD2/ANKK1 polymorphism (rs1800497), suggesting that A-carriers of rs1800497 are significantly more sensitive to motivation in order to improve during working memory (WM) training. Using data from the two large-scale imaging genetic data sets, IMAGEN (n=1080, age 13-15 years) and BrainChild (n∼300, age 6-27), we investigated whether rs1800497 is associated with WM. In the IMAGEN data set, we tested whether VS/caudate activation during reward anticipation was associated with WM performance and whether rs1800497 and VS/caudate activation interact to affect WM performance. We found that rs1800497 was associated with WM performance in IMAGEN and BrainChild. Higher VS and caudate activation during reward processing were significantly associated with higher WM performance (p<0.0001). An interaction was found between the DRD2/ANKK1 polymorphism rs1800497 and VS activation during reward anticipation on WM (p<0.01), such that carriers of the minor allele (A) showed a significant correlation between VS activation and WM, whereas the GG-homozygotes did not, suggesting that the effect of VS BOLD on WM is modified by inter-individual genetic differences related to D2 dopaminergic transmission.

Developmental change in proactive interference across the life span: Evidence from two working memory tasks.

Working memory (WM) as the ability to temporarily maintain and manipulate various kinds of information is known to be affected by proactive interference (PI) from previously relevant contents, but studies on developmental changes in the susceptibility to PI are scarce. In the present study, we investigated life span development of item-specific PI. To this end, 92 individuals between the ages of 8 and 74 years completed a recent-probes task and an n-back task that both composed experimental manipulations of PI. Regarding global WM development, young adults had higher WM performance than children and older adults in both tasks. Significant PI × Age interactions revealed that susceptibility to PI changed over the life span in both tasks, whereas the developmental course of PI differed between the tasks: Children committed more PI-related errors than young adults in the recent-probes task but showed marginally less PI in the n-back task. Regarding reaction time costs, children did not differ from adults in the recent-probes task and were less affected than adults in the n-back. Older adults showed more PI-related errors than young adults in both tasks. Therefore, as expected, item-specific PI changed over the life span with the young adults being less susceptible to PI than children and older adults. The diverging developmental effects of PI across both tasks, especially in the children, are supposed to reflect different causes for the difficulties regarding resisting PI in children and older adults. These might concern differently developed underlying cognitive processes such as inhibition or recollection, or different responses to task demands across both tasks.