Search

Task representations are critical for cognitive control and adaptive behavior. The hierarchical organization of task representations allows humans to maintain goals, integrate information across varying contexts, and select potential responses. In this study we characterized the structure and interactive dynamics of task representations that facilitate cognitive control. Human participants (both males and females) performed a hierarchical task that required them to select a response rule while considering the contingencies from different contextual inputs. By applying time- and frequency-resolved representational similarity analysis to human electroencephalography data, we characterized properties of task representations that are otherwise difficult to observe. We found that participants formed multiple representations of task-relevant contexts and features from the presented stimuli, beyond simple stimulus–response mappings. These disparate representations were hierarchically structured, with higher-order contextual representations dominantly influencing subordinate representations of task features and response rules. Furthermore, this cascade of top-down interactions facilitated faster responses. Our results describe key properties of task representations that support hierarchical cognitive control. [ABSTRACT FROM AUTHOR]

One of the proposed neural mechanisms involved in working memory is coupling between the theta phase and gamma amplitude. For example, evidence from intracranial recordings shows that coupling between hippocampal theta and cortical gamma oscillations increases selectively during working memory tasks. Theta-gamma phase-amplitude coupling can also be measured non-invasively through scalp EEG; however, EEG can only assess coupling within cortical areas, and it is not yet clear if this cortical-only coupling is truly memory-specific, or a more general phenomenon. We tested this directly by measuring cortical coupling during three different conditions: a working memory task, an attention task, and a passive perception condition. We find similar levels of theta-gamma coupling in all three conditions, suggesting that cortical theta-gamma phase-amplitude coupling is not a memory-specific signal, but instead reflects some other attentional or perceptual processes. Implications for understanding the brain dynamics of visual working memory are discussed. [ABSTRACT FROM AUTHOR]

The present studies investigated how three core aspects of executive functioning may be influenced by the presence of depth information. Specifically, participants were assigned to one of three executive functioning tasks: working memory (i.e., a change detection task), selective attention (i.e., a visual search task), or inhibitory control (i.e., a flanker task). For all three tasks, participants completed trials where the items in the display were presented either all in one depth plane or the target item was isolated in depth. For the working memory and selective attention tasks, there was an additional condition where items were evenly distributed across two depth planes. Each task also had multiple levels of difficulty to explore if task conditions influence the effect of depth information. Results indicated that although depth information can improve both working memory and selective attention performance, this benefit is specific to the task difficulty and depth information can even hinder performance under certain circumstances. Depth information did not appear to influence inhibitory control performance. Future work is required to investigate if depth can improve inhibitory control performance, and how/what task conditions influence the benefit of depth information. Until further research is completed, researchers and designers should be cautious when implementing multidimensional (3D) displays, as it remains unclear if the performance benefits of including depth information outweigh the present costs. [ABSTRACT FROM AUTHOR]

As more and more people stay inside the building for a long time, the indoor environment has a great effect on their health, mood, and work efficiency. Electroencephalography (EEG) signals reflect electrical activity originating from neuronal firing when a task or activity is performed. Since there was no study on the effect of indoor air on nerves, this study utilized EEG to preliminarily explore the brain functions of subjects during working memory tasks with different difficulties. The subjects were divided into two groups according to the volatile organic compounds (VOCs) as odor irritants in the air. We expected to find the difference in subjects' EEG signals between VOCs and low‐VOCs. The EEG signals from 60 electrodes were analyzed by event‐related potential (ERP), event‐related spectral power (ERSP), and correlation network methods to describe the brain activity. We compared the results of subjects in VOCs and low‐VOCs and found significant differences between ERP and ERSP in the alpha band during a simple working memory task. Subjects were more sensitive to the VOCs in simple tasks than in complex tasks. Our work provided evidence of odor effects on brain functions and could be used to guide the design of indoor odor in home, offices, and classrooms. [ABSTRACT FROM AUTHOR]

The working memory Stroop task is to name the color of a rectangular patch with keypress while holding a color word in working memory. Previous studies using this variant of the Stroop task have shown that congruency between the color patch and the color word significantly affects both color naming and working memory, with the worsening of task performance when the color patch is semantically incongruent rather than congruent with the color word. However, it remains unclear with regard to cognitive mechanisms underlying such congruency effects in the working memory Stroop task. By including a control condition among the congruent and incongruent conditions in a working memory Stroop task, the present study showed that nearly all of the working memory Stroop effect can be facilitation, and that interference, if present, is markedly smaller than facilitation in this form of the Stroop effect. There was also a critical contrast between the working memory and classic Stroop effects in terms of facilitation and interference, with larger facilitation and smaller interference in the working memory Stroop effect than in the classic Stroop effect. Moreover, working memory for a color word can be either facilitated or interfered with by the perceptual judgment (color naming) of an interposed color patch during the retention interval, depending on whether the color patch is semantically congruent or incongruent with the color word. Together, these results suggest that both facilitation and interference mechanisms can contribute to the overall congruency effects in the working memory Stroop task. [ABSTRACT FROM AUTHOR]

Value-driven attention capture (VDAC) occurs when previously rewarded stimuli capture attention and impair goal-directed behavior. In a working memory (WM) task with VDAC-related distractors, we observe behavioral variability both within and across individuals. Individuals differ in their ability to maintain relevant information and ignore distractions. These cognitive components shift over time with changes in motivation and attention, making it difficult to identify underlying neural mechanisms of individual differences. In this study, we develop the first participant-specific feedforward neural network models of reaction time from neural data during a VDAC WM task. We used short epochs of electroencephalography (EEG) data from 16 participants to develop the feedforward neural network (NN) models of RT aimed at understanding both WM and VDAC. Using general linear models (GLM), we identified 20 EEG features to predict RT across participants ( r = 0.53 ± 0.08 ). The linear model was compared to the NN model, which improved the predicted trial-by-trial RT for all participants ( r = 0.87 ± 0.04 ). We found that right frontal gamma-band activity and fronto-posterior functional connectivity in the alpha, beta, and gamma bands explain individual differences. Our study shows that NN models can link neural activity to highly variable behavior and can identify potential new targets for neuromodulation interventions. [ABSTRACT FROM AUTHOR]

Previous examinations of working memory impairments in children with attention-deficit/hyperactivity disorder (ADHD) have predominantly focused on discreet visuospatial and phonological subsystem processes, as well as the domain-general central executive. The episodic buffer component of working memory, a neurocognitive process that allows for temporary storage and maintenance of bound episodes/features of information, is understudied in ADHD and initial findings have been equivocal. Heterogeneity in previous findings may reflect between-study methodological variability, floor effects unrelated to episodic buffer processes (i.e., excessive central executive demands), and limitations associated with previous investigations' use of novel paradigms. This study examined ADHD-related episodic buffer processing via an established paradigm (Allen et al., 2006) in well-defined groups of children with attention-deficit/hyperactivity disorder (ADHD) and typically developing peers (TD). Seventy-one children (ADHD n = 34, TD n = 37) aged 8–12 years (M = 9.81, SD = 1.50; 32% female) completed two conditions of a computerized working memory task that presented single feature stimuli (color and shape), and a third condition that presented dual-feature stimuli (color/shape binding). Overall, the ADHD group exhibited a large-magnitude deficit during the color/shape binding condition (d =.77), and both groups evinced worse performance accuracy in the color/shape binding condition compared to the single feature color and shape conditions. Collectively, these findings appear to provide evidence that children with ADHD exhibit large magnitude episodic buffer deficits that are not attributable to visuospatial subsystem or domain-general central executive processes. [ABSTRACT FROM AUTHOR]

This study applies a neutrosophic-entropy-based clustering algorithm (NEBCA) to analyze the fMRI signals. We consider the data obtained from four different working memory tasks and the brain's resting state for the experimental purpose. Three non-overlapping clusters of data related to temporal brain activity are determined and statistically analyzed. Moreover, we used the Uniform Manifold Approximation and Projection (UMAP) method to reduce system dimensionality and present the effectiveness of NEBCA. The results show that using NEBCA, we are able to distinguish between different working memory tasks and resting-state and identify subtle differences in the related activity of brain regions. By analyzing the statistical properties of the entropy inside the clusters, the various regions of interest (ROIs), according to Automated Anatomical Labeling (AAL) atlas crucial for clustering procedure, are determined. The inferior occipital gyrus is established as an important brain region in distinguishing the resting state from the tasks. Moreover, the inferior occipital gyrus and superior parietal lobule are identified as necessary to correct the data discrimination related to the different memory tasks. We verified the statistical significance of the results through the two-sample t-test and analysis of surrogates performed by randomization of the cluster elements. The presented methodology is also appropriate to determine the influence of time of day on brain activity patterns. The differences between working memory tasks and resting-state in the morning are related to a lower index of small-worldness and sleep inertia in the first hours after waking. We also compared the performance of NEBCA to two existing algorithms, KMCA and FKMCA. We showed the advantage of the NEBCA over these algorithms that could not effectively accumulate fMRI signals with higher variability. [ABSTRACT FROM AUTHOR]

Routine action sequences can share a great deal of similarity in terms of their stimulus response mappings. As a consequence, their correct execution relies crucially on the ability to preserve contextual and temporal information. However, there are few empirical studies on the neural mechanism and the brain areas maintaining such information. To address this gap in the literature, we recently recorded the blood‐oxygen level dependent (BOLD) response in a newly developed coffee–tea making task. The task involves the execution of four action sequences that each comprise six consecutive decision states, which allows for examining the maintenance of contextual and temporal information. Here, we report a reanalysis of this dataset using a data‐driven approach, namely multivariate pattern analysis, that examines context‐dependent neural activity across several predefined regions of interest. Results highlight involvement of the inferior‐temporal gyrus and lateral prefrontal cortex in maintaining temporal and contextual information for the execution of hierarchically organized action sequences. Furthermore, temporal information seems to be more strongly encoded in areas over the left hemisphere. Routine action sequences critically rely on neural mechanisms maintaining contextual and temporal information to disambiguate similar tasks (e.g. making coffee or tea). In this study we show the involvement of areas in temporal and lateral prefrontal cortices in maintaining temporal and contextual information for the execution of hierarchically‐organized action sequences. [ABSTRACT FROM AUTHOR]

An individualized model that predicts trial‐by‐trial working memory performance is instrumental for personalized interventions. Here, we propose a single‐trial electroencephalography (EEG) classification process predicting individuals' responses, that is, target correct versus target non‐correct during a working memory task, N‐back. We used event‐related (de‐)synchronization (ERD and ERS) prior to an anticipatory cue as features. The proposed comprehensive process addresses single‐trial EEG classification challenges such as temporal overlap between training and testing datasets, feature selection's stability, and significance of the classification accuracy which have been often overlooked. Our model identified for the first time a few (ranged between 4 and 10) brain regions and oscillations where ERD and ERS predicted an individual's performance. Mean (SD) prediction accuracy across 50 participants (mean age [SD] = 28.56 [7.55]) was 69.51% (8.41). Accuracy was significantly above chance in 34 participants. This machine learning‐based approach provides a proof of principle for individualizing EEG targets for potential interventions. [ABSTRACT FROM AUTHOR]

Some theories propose that human cumulative culture is dependent on explicit, system-2, metacognitive processes. To test this, we investigated whether access to working memory is required for cumulative cultural evolution. We restricted access to adults' working-memory (WM) via a dual-task paradigm, to assess whether this reduced performance in a cultural evolution task, and a metacognitive monitoring task. In total, 247 participants completed either a grid search task or a metacognitive monitoring task in conjunction with a WM task and a matched control. Participants' behaviour in the grid search task was then used to simulate the outcome of iterating the task over multiple generations. Participants in the grid search task scored higher after observing higher-scoring examples, but could only beat the scores of low-scoring example trials. Scores did not differ significantly between the control and WM distractor blocks, although more errors were made when under WM load. The simulation showed similar levels of cumulative score improvement across conditions. However, scores plateaued without reaching the maximum. Metacognitive efficiency was low in both blocks, with no indication of dual-task interference. Overall, we found that taxing working-memory resources did not prevent cumulative score improvement on this task, but impeded it slightly relative to a control distractor task. However, we found no evidence that the dual-task manipulation impacted participants' ability to use explicit metacognition. Although we found minimal evidence in support of the explicit metacognition theory of cumulative culture, our results provide valuable insights into empirical approaches that could be used to further test predictions arising from this account. [ABSTRACT FROM AUTHOR]

Little is known about how dopamine (DA) neuron firing rates behave in cognitively demanding decision-making tasks. Here, we investigated midbrain DA activity in monkeys performing a discrimination task in which the animal had to use working memory (WM) to report which of two sequentially applied vibrotactile stimuli had the higher frequency. We found that perception was altered by an internal bias, likely generated by deterioration of the representation of the first frequency during the WM period. This bias greatly controlled the DA phasic response during the two stimulation periods, confirming that DA reward prediction errors reflected stimulus perception. In contrast, tonic dopamine activity during WM was not affected by the bias and did not encode the stored frequency. More interestingly, both delay-period activity and phasic responses before the second stimulus negatively correlated with reaction times of the animals after the trial start cue and thus represented motivated behavior on a trial-by-trial basis. During WM, this motivation signal underwent a ramp-like increase. At the same time, motivation positively correlated with accuracy, especially in difficult trials, probably by decreasing the effect of the bias. Overall, our results indicate that DA activity, in addition to encoding reward prediction errors, could at the same time be involved in motivation and WM. In particular, the ramping activity during the delay period suggests a possible DA role in stabilizing sustained cortical activity, hypothetically by increasing the gain communicated to prefrontal neurons in a motivation-dependent way. [ABSTRACT FROM AUTHOR]

Working memory is a subcategory of short‐term memory that voluntarily maintains behaviourally relevant information to prepare for a subsequent action. An established theory is that working memory is supported by the prefrontal cortex (PFC) for executive control, while the hippocampus (HPC) is largely involved in long‐term episodic memory. Recent studies suggest that the HPC is also involved in perception and short‐term storage. However, it remains unclear whether the HPC supports active maintenance of short‐term memory as working memory. To address this question, we devised a new delayed matching‐to‐sample task in which two visual items were presented at different locations one by one as samples. The sequential presentations of sample stimuli allowed us to dissociate the contents of working memory (i.e., identities and locations of two samples) from the constituent perceived information of single samples. By applying representational similarity analysis (RSA) to the blood‐oxygen‐level‐dependent (BOLD) signals of human participants, we investigated the delay activity after the two sample presentations. The results of the RSA showed that the right HPC signalled only the second sample as a conjunctional representation of its item identity and location. In contrast, the right PFC, including both lateral and medial parts, represented the conjunctional information of both samples. These results suggested that the HPC may support short‐term memory for retrospective coding to retain information of the last event rather than for prospective coding coupled with working memory. [ABSTRACT FROM AUTHOR]

Introduction: Cigarette smoking is known to modulate brain metabolism and brain function. How the dynamics of these metabolic alterations influence the active performance of higher order cognitive tasks in smokers, compared to non-smokers, is still unclear. The present exploratory study sought to examine the impact of smoking on the "complete" metabolic profile while the participants performed a working memory (N-back) task. Methods: The study sample consisted of 40 young male healthy participants (smokers [n = 20] and non-smokers [n = 20]). Functional magnetic resonance spectroscopy data were acquired using a 3 T whole-body MR system. Data analysis was performed using Java-based Magnetic Resonance User Interface software, and metabolite ratios with respect to creatine (Cr) were calculated. Results: On a behavioural level, smokers showed worse performance (measured by d') than non-smokers. However, we observed significant differences in the metabolite concentrations in smokers compared to non-smokers, which also changed over the course of the N-back task. A significant effect of the group was observed with smokers showing lower glutamate/Cr (Glx/Cr) and choline/Cr (Cho/Cr) ratios than non-smokers. Further, N-acetyl aspartate (NAA/Cr) and Cho/Cr ratios were significantly different during the rest and the task conditions. In addition, our results demonstrated the metabolite interactions (NAA and Cho, Glx and myo-inositol [mI], and Cho and mI). Conclusion: Further studies are necessary to shed more light on the association between smoking behaviours and metabolic alterations. However, our preliminary findings would assist in this future research to have a complete understanding of the metabolite interactions not only in smoking but also in addiction research. [ABSTRACT FROM AUTHOR]

Judgments of liking and beauty appear to be expressions of a common hedonic state, but they differ in how they engage cognitive processes. We hypothesised that beauty judgments place greater demands on limited executive resources than judgments of liking. We tested this hypothesis by asking two groups of participants to judge works of visual art for their beauty or liking while having to remember the location of 1, 3, or 5 dots in a 4 by 4 matrix. We also examined the effect of individual differences in working memory capacity. Our results show that holding information about the location of the dots in working memory delayed judgments of beauty but not of liking. Also, the greater participants' working memory capacity, the faster they completed the working memory task when judging liking, but not when judging beauty. Our study provides evidence that judging beauty draws more on working memory resources than judging liking. [ABSTRACT FROM AUTHOR]

Task‐based functional magnetic resonance imaging (MRI) neuroimaging for the study of cognitive neuroscience provides insight into how the brain responds to increasing cognitive demands. Theoretical models of neural–cognitive relationships define neural efficiency and neural capacity as two parameters to describe the rate of gain of brain activity and the upper limits of the increases, respectively. Although qualitatively well described, there are limited discussions and demonstrations of estimating these parameters from data. The current work presents a method using a quadratic equation model of cognitive demands. The methods were applied to 21 healthy young adults while engaging in four levels of the verbal n‐back working memory task (0, 1, 2 and 3‐back). Measures of the area under the curve captured both linear and curvilinear responses to quantify the locations and amounts of task‐related increases in brain activity. In addition, we calculated voxel‐wise maps of neural efficiency and neural capacity. Results showed increases in brain activation in regions typically involved in working memory. The relationships between increasing cognitive demands and brain activity also differed across the brain within and between individuals, as indicated by differential neural efficiency and neural capacity values. This approach provides tools for evaluating current theories about the relationships between brain activity and cognition. Neural efficiency and neural capacity provide physiological measures of brain activity, which will help evaluate how age, disease and intervention processes affect brain activity. Finally, all presented methods are readily applicable using standard current software packages for neuroimaging. [ABSTRACT FROM AUTHOR]

An animals' ability to learn how to make decisions based on sensory evidence is often well described by Reinforcement Learning (RL) frameworks. These frameworks, however, typically apply to event-based representations and lack the explicit and fine-grained notion of time needed to study psychophysically relevant measures like reaction times and psychometric curves. Here, we develop and use a biologically plausible continuous-time RL scheme of CT-AuGMEnT (Continuous-Time Attention-Gated MEmory Tagging) to study these behavioural quantities. We show how CT-AuGMEnT implements on-policy SARSA learning as a biologically plausible form of reinforcement learning with working memory units using 'attentional' feedback. We show that the CT-AuGMEnT model efficiently learns tasks in continuous time and can learn to accumulate relevant evidence through time. This allows the model to link task difficulty to psychophysical measurements such as accuracy and reaction-times. We further show how the implementation of a separate accessory network for feedback allows the model to learn continuously, also in case of significant transmission delays between the network's feedforward and feedback layers and even when the accessory network is randomly initialized. Our results demonstrate that CT-AuGMEnT represents a fully time-continuous biologically plausible end-to-end RL model for learning to integrate evidence and make decisions. [ABSTRACT FROM AUTHOR]

The mood induction paradigm has been an important tool for investigating the effects of negative emotional states on working memory (WM) executive functions. Though some evidence showed that negative mood has a differential effect on verbal and visuospatial WM, other findings did not report a similar effect. To explore this issue, we examined the negative mood's impact on verbal and visuospatial WM executive tasks based on grammatical reasoning and visuospatial rotation. Participants with no anxiety or depression disorders performed the tasks before and after negative (n = 14) or neutral (n = 13) mood induction. Participants' mood at the beginning and the end of the session was assessed by the Present Mood States List (LEAP) and word valence rating. The analyses showed changes in the emotional state of the negative group (ps <.03) but not of the neutral group (ps >.83) in the LEAP instrument. No significant differences between groups were observed in the WM tasks (ps >.33). Performance in the visuospatial WM task improved after mood induction for both groups (p <.05), possibly due to a practice effect. In sum, our findings challenge the view that negative mood modulates WM executive functions; thus, they were discussed considering the similarities and differences between studies that found negative mood effects on WM and those that did not find. Different WM tasks tap distinct processes and components, which may underlie behavioral effects of negative mood on WM tasks. [ABSTRACT FROM AUTHOR]

Multiple tasks have been used to demonstrate the relation between numbers and space. The classic interpretation of these directional spatial–numerical associations (d-SNAs) is that they are the product of a mental number line (MNL), in which numerical magnitude is intrinsically associated with spatial position. The alternative account is that d-SNAs reflect task demands, such as explicit numerical judgements and/or categorical responses. In the novel "Where was The Number?" task, no explicit numerical judgements were made. Participants were simply required to reproduce the location of a numeral within a rectangular space. Using a between-subject design, we found that numbers, but not letters, biased participants' responses along the horizontal dimension, such that larger numbers were placed more rightward than smaller numbers, even when participants completed a concurrent verbal working memory task. These findings are consistent with the MNL account, such that numbers specifically are inherently left-to-right oriented in Western participants. [ABSTRACT FROM AUTHOR]

The capacity of working memory is limited and undergoes important developmental changes during childhood. One proposed reason for the expansion of working memory capacity during childhood is the emergence and increased efficiency of active maintenance mechanisms, such as that of refreshing. Refreshing is a proposed mechanism to keep information active in working memory by bringing memory items back into the focus of attention. One prevalent view is that the spontaneous use of refreshing emerges around the age of 7 and becomes more efficient during middle childhood and beyond. Using a novel approach to examine refreshing in children in Experiment 1, we show, against common conceptions, that simply giving free time in a basic working memory task does not lead to spontaneous refreshing in 9–12‐year‐old children. Instead, their focus of attention appears to linger on the last‐presented memory item, even when ample time for refreshing is provided. Experimentally imposing the use of refreshing in Experiment 2, however, showed that children in this age range are able to switch their focus of attention away from the last‐presented item in switch to another memory item. Thus, the current study uncovers that children in middle childhood do not always spontaneously switch attention away from the last‐presented memory item to refresh the entire list, even though they are able to switch attention away from the last‐presented memory item when instructed to do so. The theoretical implications of these findings are discussed. [ABSTRACT FROM AUTHOR]

Single-bout focused-attention meditation (FAM) and open-monitoring meditation (OMM) are assumed to bias metacontrol states towards more persistent versus more flexible processing, respectively. In Experiment 1, we tested whether monitoring and updating of working memory (WM) representations in an N -back task with high (3-back), medium (2-back), and low (1-back) WM demands (varied within participants) is affected by preceding single-bout FAM or OMM meditation (varied between participants and compared with a control group). The results showed that FAM promotes WM performance in the medium (2-back), but not in the high (3-back) or low (1-back) demand condition, whereas OMM did not affect WM performance. A replication of the 2-back condition only (Experiment 2) showed no meditation effect, but a replication of the 3-back condition only (Experiment 3) produced a similar pattern as the 2-back condition in Experiment 1, with FAM promoting performance compared with OMM and the control condition. Taken together, these findings suggest that the single-bout FAM does promote WM performance but only if the capacity demands are neither too high nor too low. [ABSTRACT FROM AUTHOR]

Variability in working memory (WM) task selection likely contributes to heterogeneity in effect size estimates of deficiencies in youth with attention-deficit/hyperactivity disorder (ADHD). This has resulted in the development of brief, easy to administer assessments such as the NIH List Sorting Working Memory (LSWM) task from the NIH Cognitive Toolbox in hopes of standardizing measurement of this construct. Unfortunately, substantial questions persist regarding the specific constructs being evaluated by this task (e.g., visuospatial [VS] or phonological [PH] WM) as well as the ability of this task to detect WM deficits in previously identified impaired groups (e.g., ADHD). The current study examines the extent to which the LSWM task is associated with VS and PHWM performance as well as symptoms of ADHD. Additionally, we examined the magnitude of differences between ADHD and Typically Developing (TD) youth on this task relative to empirically derived WM tasks utilized in the past. Forty-six children (25 ADHD, 21 TD) completed multiple WM tasks. The LSWM task was moderately associated with PHWM and demonstrated relatively weaker associations with VSWM. Symptoms of inattention and hyperactivity/impulsivity were unrelated to the LSWM task; whereas tasks assessing PH and VSWM were moderately associated with inattention and weakly associated with hyperactivity (VSWM only). No significant between-group differences in performance emerged on the LSWM task; however, significant large-magnitude group differences were observed on both the PH and VSWM tasks. These findings suggest that the LSWM task may lack the ability to detect WM difficulties in youth with ADHD. [ABSTRACT FROM AUTHOR]

The association between cannabis exposure and working memory impairment and its neural substrates remain unclear. In this cross‐sectional observational study, we investigated this by examining the relationship between frequency of exposure to cannabis, working memory performance and regional brain volumes and tested whether lower volumes of cortical and subcortical structures mediate the association between cannabis exposure and working memory deficit using the Human Connectome Project data from 234 individuals with self‐reported cannabis exposure and 174 individuals unexposed to cannabis. We tested the relationship between self‐reported frequency of cannabis exposure and list‐sorting working memory task performance (total number of correct responses), between T1 weighted MRI‐derived regional grey‐matter volumes and working memory task performance as well as between frequency of cannabis exposure and brain volumes after controlling for potential confounders. Finally, mediation analysis was carried out to test whether deficit in working memory performance associated with cannabis use was mediated by its association with lower grey‐matter volume. Participants who reported higher frequency of cannabis use tended to have lower number of correct responses in the list‐sorting working memory task and lower bilateral hippocampal volumes. Association between severity of cannabis exposure as indexed by frequency of cannabis use and impairment in working memory was mediated by lower left hippocampal volume in cannabis users. We report evidence in support of the left hippocampus volume‐mediated working memory impairment associated with recreational cannabis exposure. Future studies employing prospective longitudinal design are necessary to examine the cause–effect relationships of cannabis exposure on working memory and brain volumes. [ABSTRACT FROM AUTHOR]

Inhibitory control is a key executive function and has been studied extensively using the stop signal task. By applying a simple race model that posits an independent race between a GO process responsible for initiation of responses and a STOP process responsible for inhibition of responses, one can estimate how long it takes an individual to inhibit an ongoing response, the stop signal reaction time. Here, we examined how stop signal reaction time can be affected by working memory. Participants engaged in a dual task; they completed a stop signal task under low and high working memory load conditions. Working memory capacity was also measured. We found that the STOP process was lengthened in the high, compared to the low, working memory load condition, as evidenced by differences in stop signal reaction time. The GO process was unaffected and working memory capacity could not account for differences across the load conditions. These results indicate that inhibitory control can be influenced by placing demands on working memory. [ABSTRACT FROM AUTHOR]

It is debated whether training with a working memory (WM) task, particularly n-back, can improve general WM and reasoning skills. Most training studies found substantial improvement in the trained task, with little to no transfer to untrained tasks. We hypothesized that training does not increase WM capacity, but instead provides opportunities to develop an efficient task-specific strategy. We derived a strategy for the task that optimizes WM resources and taught it to participants. In two sessions, 14 participants who were taught this strategy performed as well as fourteen participants who trained for 40 sessions without strategy instructions. To understand the mechanisms underlying the no-instruction group's improvement, participants answered questionnaires during their training period. Their replies indicate that successful learners discovered the same strategy and their improvement was associated with this discovery. We conclude that n-back training allows the discovery of strategies that enable better performance with the same WM resources. [ABSTRACT FROM AUTHOR]

• Behavior and ERPs during the recognition phase of Working Memory are studied in ADHD. • RTs and errors were higher in ADHD subjects compared to the control group. • ADHD children showed marginal differences in N2pc with respect to control children. • The reduced Pd component in ADHD children suggest a difficulty for suppressing distractors in ADHD. • There is evidence of neural impairment in ADHD children during the recognition phase of the DMTS WM task. Impairment of executive functions including attention and working memory (WM) have been proposed as an important feature of Attention Deficit and Hyperactivity Disorder (ADHD). During the recognition phase of a delayed match-to-sample test (DMTS) a reduced N2pc component, related to the attentional selection of the memorized item and a reduced distractor positivity (Pd), related to the processing suppression of distractors are expected in ADHD subjects. For the purpose of the study, twenty-nine ADHD subjects diagnosed with a structured interview and the DuPaul questionnaire, were included in the study. Thirty-four control subjects were recruited from public schools and matched by age (from 6 to 17 years old) and gender with the ADHD group. Reaction times (RTs), errors, and Event Related Potentials (ERPs) were obtained in a DMTS task during the recognition phase in correct trials. RTs and errors were higher in ADHD subjects compared to the control group. Specifically, errors were much higher in ADHD than in controls. The cluster mass permutation statistics showed a significant N2pc component in both groups during the recognition phase, but a significant Pd component was present only in controls. The present results suggest that in correct trials ADHD children use the same neural resources to select the memorized item from WM with similar efficacy than controls, although a lower Pd suggests a difficulty in suppressing distractors. [ABSTRACT FROM AUTHOR]

Purpose: Although investigative interviewers receive training in interviewing techniques, they often fail to comply with recommended practices. Interviewers are required to actively listen, accurately remember information, think of questions to ask, make judgements, and seek clarification, whilst conducting interviews with witnesses, victims, or suspects. The current study examined the impact of increased cognitive load on mock interviewers' recall of a witness's account. Method: Participants took the role of an investigative interviewer in one of three conditions, high cognitive load (HCL), moderate cognitive load (MCL), or no cognitive load (NCL). Participants watched a video‐recorded free narrative of a child witness during which they followed condition‐relevant task instructions. Each participant rated their perceived cognitive load during their task and then recalled (free and cued recall) the content of the witness's account. Results: Participants in the HCL and MCL conditions perceived higher cognitive load and demonstrated poorer performance on the free recall task than those in the NCL condition. Participants in the HCL condition demonstrated poorer performance on the cued recall task compared to participants in the NCL condition. Conclusions: The cognitive demands required to complete an investigative interview task led to an increased perceived cognitive load and had a negative impact on recall performance for mock interviewers. Accurately recalling what has been reported by a witness is vital during an investigation. Inaccurate recall can impact on interviewers' questioning and their compliance with recommended interviewing practices. Developing and practising interview techniques may help interviewers to better cope with the high cognitive demands of investigative interviewing. [ABSTRACT FROM AUTHOR]

Aim of the study: The aim of this longitudinal study was twofold: first, to determine whether the relationship between working memory measures and language performance in young English language learners (ELL) remains constant over the year. The second aim was to determine if performance on working memory tasks predicts future performance on language measures. Methodology: The participants were 27 ELLs between the ages of 5 and 6 years who were in their first year of formal schooling and attended the same mid-low socioeconomic status school in South Africa. The participants were tested three times throughout the year on tasks of working memory and an English assessment battery. Data analysis and results: Mixed effects models and multiple linear regression were used to address the aims of the study. The first aim of the study showed that there are significant correlations between all working memory measures and all language measures in varying strengths across the year. The second research aim further elaborated on this by showing that both phonological working memory and non-verbal complex working memory are implicated in the acquisition of syntax, semantics and pragmatics at different points throughout the year. Implications and originality: Language acquisition in ELLs is not a stand-alone process and working memory measures may be able to predict future language outcomes. This could indicate that working memory measures may be used as an indicator for who may need language intervention, at a time when the ELL only has limited English proficiency and limited English exposure. This research is the first of its kind to originate from Africa, with a sample from low socioeconomic, culturally and linguistically diverse circumstances who are exposed to English consistently for the first time and are tested with working memory tasks with less strong language components. [ABSTRACT FROM AUTHOR]

The mechanisms of task-positive and task-negative activations are basic elements for exploring cognitive functions, impairment of which would trigger degenerative neurological diseases. Our research group combined the default mode network (DMN) with the working memory model, chosen as the task positive network (TPN), to carry out computational simulation under various stimulus conditions. The paper has demonstrated the following results: 1) task-positive (TPN) and task-negative networks (TNN) represented antagonistic neural activities; 2) the degree of attenuation in TNN was enhanced with increasing stimulus directions on the working memory; 3) neural activities in TNN decreased as long as that in working memory-related brain regions increase; 4) the more difficult the working memory task was, the more rapidly neural activities in TNN attenuated. Since the task-negative activation was the main characteristic of DMN, mutual inhibition between DMN and TPN was the key of the antagonism between the two networks with different properties. [ABSTRACT FROM AUTHOR]

This study aimed to elucidate the mechanism of detecting differences between a current line orientations and line orientations retained in working memory (WM). The results were compared with the data obtained in a WM experiment for spatial patterns. The study involved 33 healthy subjects with normal vision. The subjects performed a WM task, and the visual event-related potentials (ERPs) and dipole simulation were analyzed in the interval 160–280 ms after the stimulus. An increase in ERP amplitude was identified as an informative marker of a mismatch between the current and retained stimuli. The increase arose simultaneously in the frontal and parietal-occipital cortical areas and was stimulus type independent. An analysis of distributed dipole sources showed that the topography of match vs. mismatch differences depends on the stimulus type. In the case of orientations, differences were more local and predominated in the caudal areas of the left hemisphere. In the case of spatial patterns, differences were more extended and prevailed in the right hemisphere. The results indicate that a common organization is characteristic of neural networks detecting a mismatch between current and retained stimuli and, on the other hand, that some rearrangements can arise in these neural networks depending on the type of information processed. [ABSTRACT FROM AUTHOR]

Past research suggests that working memory (WM) and motor control may engage similar cognitive and neural mechanisms in older adults, particularly when task difficulty increases. However, much of this evidence arises from comparisons across behavioral and imaging studies that test only one of the foregoing functional domains. The current study used fMRI within the same group of older adults to investigate whether WM and motor control recruit common mechanisms, and whether recruitment increased with task demand and age. A conjunction analysis across WM and motor tasks revealed engagement of several frontoparietal regions as a function of increasing task demand. A separate conjunction analysis which included age as a predictor showed comparable regions exhibit increased recruitment with both increasing task demand and age. Results suggest that the recruitment of common frontoparietal regions across WM and motor tasks in response to task difficulty is maintained across the older adult lifespan. [ABSTRACT FROM AUTHOR]

We used the Multi-Item Localisation (MILO) task to examine search through two sequences. In Sequential blocks of trials, six letters and six digits were touched in order. In Mixed blocks, participants alternated between letters and digits. These conditions mimic the A and B variants of the Trail Making Test (TMT). In both block types, targets either vanished or remained visible after being touched. There were two key findings. First, in Mixed blocks, reaction times exhibited a saw-tooth pattern, suggesting search for successive pairs of targets. Second, reaction time patterns for vanish and remain conditions were identical in Sequential blocks—indicating that participants could ignore past targets—but diverged in Mixed blocks. This suggests a breakdown of inhibitory tagging. These findings may help explain the elevated completion times observed in TMT-B, relative to TMT-A. [ABSTRACT FROM AUTHOR]

Motivationally/emotionally engaging stimuli are strong competitors for the limited capacity of sensory and cognitive systems. Thus, they often act as distractors, interfering with performance in concurrent primary tasks. Keeping task-relevant information in focus while suppressing the impact of distracting stimuli is one of the functions of working memory (WM). Macroscopic brain oscillations in the alpha band (8–13 Hz) have recently been identified as a neural correlate of WM processing. Using electroencephalography, we examined the extent to which changes in alpha power and inter-site connectivity during a typical WM task are sensitive to load and emotional distraction. Participants performed a lateralized change-detection task with two levels of load (four vs. two items), which was preceded by naturalistic scenes rated either as unpleasant or neutral, acting as distractors. The results showed the expected parieto-occipital alpha reduction in the hemisphere contralateral to the WM task array, compared to the ipsilateral hemisphere, during the retention interval. Selectively heightened oscillatory coupling between frontal and occipital sensors was observed (1) during the retention interval as a function of load, and (2) upon the onset of the memory array, after viewing neutral compared to unpleasant distractors. At the end of the retention interval, we observed greater coupling during the unpleasant compared to the neutral condition. These findings are consistent with the notions that (1) representing more items in WM requires greater interconnectivity across cortical areas, and (2) unpleasant emotional distractors interfere with subsequent WM processing by disrupting processing during the encoding stage. [ABSTRACT FROM AUTHOR]

Enhancing creative problem-solving is increasingly important in a modern globalized society. Previous research has shown that creative problem-solving can be improved if the mind is allowed to wander during time set aside from solving a problem, known as the incubation period. However, some research also suggests that mind wandering leads to negative affect. Our study aims to clarify the effect of mind wandering during the incubation stage on both creative problem-solving and mood while controlling for the effect of working memory capacity. Fifty-two students (both undergraduate and graduates) completed a working memory task and repeated a creative problem-solving task at intervals before and after an incubation period. At the end of the incubation period, we measured participants' frequency of mind wandering and their moods. Results showed that the group with the higher frequency of mind wandering showed the most improvement in one indicator of creativity, flexibility, although this finding was not significant after adjusting for the other four facets. Moreover, our findings indicate that as creativity improved, more negative affect was generated. Our results suggest that mind wandering during the incubation stage could be used to generate more diverse ideas but also suggest that there is a risk attached. Further research should explore how specific features of mind wandering might improve creativity without generating negative affect. [ABSTRACT FROM AUTHOR]

This article reports an investigation of how inhibition contributes to fluid reasoning when it is decomposed into the reasoning ability, item-position, and speed components to control for possible method effects. Working memory was also taken into consideration. A sample of 223 university students completed a fluid reasoning scale, two tasks tapping prepotent response inhibition, and two working memory tasks. Fixed-links modeling was used to separate the effect of reasoning ability from the effects of item-position and speed. The goodness-of-fit results confirmed the necessity to consider the reasoning ability, item-position, and speed components simultaneously. Prepotent response inhibition was only associated with reasoning ability. This association disappeared when working memory served as a mediator. Taken together, these results reflect the inhomogeneity of what is tapped by the fluid reasoning scale on one hand and, on the other, suggest inhibition as an important component of working memory. [ABSTRACT FROM AUTHOR]

We used the Multi-Item Localisation (MILO) task to examine search through two sequences. In Sequential blocks of trials, six letters and six digits were touched in order. In Mixed blocks, participants alternated between letters and digits. These conditions mimic the A and B variants of the Trail Making Test (TMT). In both block types, targets either vanished or remained visible after being touched. There were two key findings. First, in Mixed blocks, reaction times exhibited a sawtooth pattern, suggesting search for successive pairs of targets. Second, reaction time patterns for vanish and remain conditions were identical in Sequential blocks--indicating that participants could ignore past targets--but diverged in Mixed blocks. This suggests a breakdown of inhibitory tagging. These findings may help explain the elevated completion times observed in TMT-B, relative to TMT-A. [ABSTRACT FROM AUTHOR]

Previous research examining whether bilinguals exhibit enhanced working memory (WM) compared to monolinguals has yielded mixed results. This inconsistency may be due to lack of sensitivity in behavioral and neuropsychological measures. The current study aimed to investigate the effects of bilingualism on WM by focusing on brain activity patterns (event-related potentials) in monolinguals and bilinguals during a WM task. We recorded brain activity while participants (26 monolingual English speakers and 28 English–French bilinguals) performed a delayed matching-to-sample task. Although performance measures were similar, electrophysiological differences were present across groups. Bilinguals exhibited larger P3b amplitudes than monolinguals, and smaller negative slow wave and N2b amplitudes during retrieval. These results suggest that bilinguals may have more cognitive resources available in WM to allocate to task completion, and that task completion may be less effortful for bilinguals than for monolinguals. [ABSTRACT FROM AUTHOR]

Background: Previous research has suggested that worry is negatively associated with working memory performance. However, it is unclear whether these findings would replicate across different worry levels and in individuals with anxiety and depressive disorders (i.e. clinical statuses). Method: One-hundred-thirty-eight participants performed a two-block working memory task (150 trials per block). Based on participants' current clinical status, four groups were considered (generalised anxiety disorder group: n = 36; clinical group with another anxiety or mood disorders: n = 33; subclinical group: n = 27; control group: n = 42). Trait worry levels were collected from all of the participants. Working memory performance was measured as accuracy and reaction time. Results: During the first block, higher worry scores were significantly associated with longer reaction times. Moreover, the generalised anxiety disorder group, clinical group, and subclinical groups demonstrated significantly longer reaction times compared to the control group in Block 1, when age was controlled for. From Block 1 to Block 2, all of the participants demonstrated a significant decrease in accuracy and reaction time, regardless of worry level or clinical status. Conclusion: The results indicate that higher worry levels negatively impact WM processing efficiency. Moreover, when age was controlled for, we found participants' clinical status to be linked with WM impairments. The results highlight the relevance of investigating the impact of different worry levels on cognitive processes across clinical and non-clinical populations. [ABSTRACT FROM AUTHOR]

Rationale: Working memory deficits are present in schizophrenia (SZ) but remain insufficiently resolved by medications. Similar cognitive dysfunctions can be produced acutely in animals by elevating brain levels of kynurenic acid (KYNA). KYNA's effects may reflect interference with the function of both the α7 nicotinic acetylcholine receptor (α7nAChR) and the glycineB site of the NMDA receptor. Objectives: The aim of the present study was to examine, using pharmacological tools, the respective roles of these two receptor sites on performance in a delayed non-match-to-position working memory (WM) task (DNMTP). Methods: DNMTP consisted of 120 trials/session (5, 10, and 15 s delays). Rats received two doses (25 or 100 mg/kg, i.p.) of L-kynurenine (KYN; bioprecursor of KYNA) or L-4-chlorokynurenine (4-Cl-KYN; bioprecursor of the selective glycineB site antagonist 7-Cl-kynurenic acid). Attenuation of KYN- or 4-Cl-KYN-induced deficits was assessed by co-administration of galantamine (GAL, 3 mg/kg) or PAM-2 (1 mg/kg), two positive modulators of α7nAChR function. Reversal of 4-Cl-KYN-induced deficits was examined using D-cycloserine (DCS; 30 mg/kg), a partial agonist at the glycineB site. Results: Both KYN and 4-Cl-KYN administration produced dose-related deficits in DNMTP accuracy that were more severe at the longer delays. In KYN-treated rats, these deficits were reversed to control levels by GAL or PAM-2 but not by DCS. In contrast, DCS eliminated performance deficits in 4-Cl-KYN-treated animals. Conclusions: These experiments reveal that both α7nAChR and NMDAR activity are necessary for normal WM accuracy. They provide substantive new support for the therapeutic potential of positive modulators at these two receptor sites in SZ and other major brain diseases. [ABSTRACT FROM AUTHOR]

The brain frontoparietal regions and the functional communications between them are critical in supporting working memory and other executive functions. The functional connectivity between frontoparietal regions are modulated by working memory loads, and are shown to be modulated by a third brain region in resting‐state. However, it is largely unknown whether the third‐region modulations remain the same during working memory tasks or were largely modulated by task demands. In the current study, we collected functional MRI (fMRI) data when the subjects were performing n‐back tasks and in resting‐state. We first used a block‐designed localizer to define the frontoparietal regions that showed higher activations in the 2‐back than the 1‐back condition. Next, we performed physiophysiological interaction (PPI) analysis using left and right middle frontal gyrus (MFG) and superior parietal lobule (SPL) regions, respectively, in three continuous‐designed runs of resting‐state, 1‐back, and 2‐back conditions. No regions showed consistent modulatory interactions with the seed pairs in the three conditions. Instead, the anterior cingulate cortex (ACC) showed different modulatory interactions with the right MFG and SPL among the three conditions. While the increased activity of the ACC was associated with decreased functional coupling between the right MFG and SPL in resting‐state, it was associated with increased functional coupling in the 2‐back condition. The observed task modulations support the functional significance of the modulations of the ACC on frontoparietal connectivity. [ABSTRACT FROM AUTHOR]

Studies have shown improved cognitive performance of action video game players (AVGPs); however, the corresponding neural correlates are still unclear. The present study aims to investigate whether the unsupervised training on action video games contributes to the visuomotor adaptation of working memory or not, considering neural measures. Twenty-seven-Channel electroencephalogram (EEG) signals from 35 participants are recorded while performing Corsi block-tapping task (CBTT), a working memory task incorporating recall of visual and sequential–spatial information, and are analyzed employing wavelet transform-based feature extraction techniques. For removing artifacts, we have used the wavelet denoising method. Different mother wavelet functions, with different thresholding algorithms, are compared. The dmeyer mother wavelet function along with Rigorous SURE soft thresholding emerged as the best combination for denoising. Comparison of wavelet energy features has revealed improved rhythmic activity in AVGPs. Also, two measures of engagement index β/(α + θ) and β/α are computed which has provided good classification accuracies with ANFIS classifier. Higher engagement indexes are found in the frontal, right parietal and occipital cortex of AVGPs. These results evidence the neurocortical modulation among the players that may attribute to the effective cognitive processes in AVGPs related to the task. [ABSTRACT FROM AUTHOR]

Math anxiety (MA) is associated with negative thoughts and emotions when encountering mathematics, often resulting in under-performance on math tasks. One hypothesized mechanism by which MA affects performance is through anxiety-related increases in working memory (WM) load, diverting resources away from mathematical computations. We examined whether this effect is specific to WM or whether the impact of MA extends to an overall depletion of executive function (EF) resources. In this fMRI experiment, we manipulated two separate factors known to impact EF demands—task-switching (TS) and increased WM load—in order to evaluate how MA relates to behavioral performance and neural activity related to mathematical calculations. Relative to a difficult non-math task (analogies), we observed MA-related deficits in math performance and reduced neural activity in a network of regions in the brain associated with arithmetic processing. In response to TS demands, higher levels of math anxiety were associated with a pattern of avoidance and disengagement. When switching from the control task, high math anxiety (HMA) was associated with disengagement from math trials, speeding through these trials, and exhibiting reduced neural activity in regions associated with arithmetic processing. The effects of math anxiety and WM were most pronounced at the lowest levels of WM load. Overall, the results of this study indicate that the effects of MA are broader than previously demonstrated and provide further insight into how EF deficits in MA might impact recruitment of neural resources that are important for successful math computations. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate whether and how users' familiarity with symbols affects the performance of complex cognitive tasks which place considerable demands on working memory resources. We combined a modified math task paradigm with our previous icon familiarity training paradigm. Participants were required to complete a mathematical task involving icons to test their ability to perform complex cognitive tasks. The complexity of the task was manipulated using three independent variables: icon familiarity (high-frequency vs. low-frequency), whether or not the equation requires substitution (substitution vs. no-substitution), and the number of steps required for solution (one step vs. two steps). The results showed that participants performed better on the equation-solving task when it used icons they were more extensively trained on. Importantly, icon familiarity interacted with the complexity of the task and the familiarity effect on performance (accuracy and response time) became greater when the complexity increased. These findings provide evidence that familiarity affects not only the ease of information retrieval but also the ease of subsequent processing activities associated with these information, which extends our understanding of how familiarity affects working memory. Moreover, our findings have practical implications for improving interaction efficiency. Before the operators formally use a digital system, they need to learn the precise meaning of those complex or unfamiliar symbols in a certain context as much as possible. [ABSTRACT FROM AUTHOR]

A traditional view of short-term working memory (STM) is that task-relevant information is maintained 'online' in persistent spiking activity. However, recent experimental and modeling studies have begun to question this long-held belief. In this review, we discuss new evidence demonstrating that information can be 'silently' maintained via short-term synaptic plasticity (STSP) without the need for persistent activity. We discuss how the neural mechanisms underlying STM are inextricably linked with the cognitive demands of the task, such that the passive maintenance and the active manipulation of information are subserved differently in the brain. Together, these recent findings point towards a more nuanced view of STM in which multiple substrates work in concert to support our ability to temporarily maintain and manipulate information. It has been commonly believed that information in short-term memory (STM) is maintained in persistent delay-period spiking activity. Recent experiments have begun to question this assumption, as the strength of persistent activity appears greater for tasks that require active manipulation of the memoranda, as opposed to tasks that require only passive maintenance. New experiments have revealed that information in STM can be maintained in neural 'hidden' states, such as short-term synaptic plasticity. Machine-learning-based recurrent neural networks have been successfully trained to solve a diversity of working memory tasks and can be leveraged to understand putative neural substrates of STM. [ABSTRACT FROM AUTHOR]

Words that represent animate entities (e.g., dog) are recalled from long-term memory more accurately than words representing inanimate entities (e.g., pan). In this research, we examined whether the animacy effect extends to working memory (WM). The potential roles of WM maintenance strategies (rehearsal and directed attention) were also examined. Participants performed serial order recall tasks with sets of 3, 4, 5 or 6 words that were either animate or inanimate. In stage 1 of Experiment 1, participants received no instructions regarding how to maintain the words. In stage 2, participants received either no instructions, sub-vocal rehearsal or directed attention instructions. In all instruction groups and at both stages, significant animacy effects were observed at set sizes of 4, 5 and 6 but not set size 3. The animacy effect was larger at set size 5 than other set sizes. In Experiment 2, participants completed the task with and without articulatory suppression. In both conditions, animacy effects were observed at set sizes 4, 5 and 6, but not at set size 3. The magnitude of the animacy effect declined as set size increased from 4 to 6. Animacy appears to enhance serial recall, but the effect is not dependent on rehearsal. [ABSTRACT FROM AUTHOR]

Summary: The present study attempts to expand our understanding of frustration, clinical symptoms, and working memory by examining the unique contribution of attention‐deficit/hyperactivity disorder symptoms and frustration to working memory capacity (WMC). A factor‐analytic framework was utilized to isolate and examine WMC based on results from three working memory tasks that were administered in counterbalanced order to control for individual differences in baseline WMC. All participants provided subjective ratings of frustration both prior to and after administration of a frustration induction. Results suggest that although we were able to systematically induce subjective frustration for participants in the experimental group relative to the control group, WMC was not associated with induced frustration in the present study. Results also indicated that inattention symptoms predicted baseline frustration levels. This work highlights the need to examine the extent to which storage/rehearsal WMC and additional process‐oriented working memory‐related performance variables are related to frustration. The data that support the findings of this study are available from the corresponding author upon request. [ABSTRACT FROM AUTHOR]

Our ability to save is greater for more familiar stimuli than for less familiar. However, the specific processes affected by familiarity are still less known. We investigate the familiarity effect on the retrieval of visual representations in a recognition task, using the retroactive cue paradigm. A visual interference task (DVN-Dynamic Visual Noise) was used as visual nature indicator of recovered representations. The familiarity, defined as to the repeated exposure to the same stimuli set, was manipulated between two groups of participants. For one group (Group with Repeated Stimuli) the experimental tests contained stimuli drawn from the same set of 8 Chinese characters. For the other group (Group with Unpublished Stimuli) the tests were formed by unpublished stimuli, drawn from a set of 483 Chinese characters. DVN was presented in the interval between the retroactive tip and the test stimulus in half the tests. The performance of both groups improves on the task recognition throughout the experimental session, but more sharply at the group that worked with Repeated Stimuli. The retrieval effect remains unchanged throughout the session and independs of familiarity, however the more familiar representation is more susceptible to DVN, suggesting the repeated exposure to the same stimuli allowed the generation of visual representations. [ABSTRACT FROM AUTHOR]

Representations of visual objects in working memory (WM) can be part-based or object-based, and we investigated whether this is determined by top-down control processes. Lateralised change detection tasks were employed where sample objects on one task-relevant side had to be memorized. Contralateral delay activity (CDA) components were measured during the retention period as electrophysiological markers of WM maintenance processes. In two critical task conditions, sample displays contained objects composed of two vertically aligned shapes. In the Parts task, test displays contained a single shape that had to be matched with either of the two sample shapes, encouraging the storage of part-based WM representations. In the Whole task, compound-shape objects shown at test had to be matched with memorized compound objects, which should facilitate the formation of object-based integrated WM representations. CDA amplitudes were significantly larger in the Parts task than in the Whole task, indicative of differences in effective WM load. This suggests that the two individual shapes were represented separately in the Parts task, whereas a single compound object was maintained in the Whole task. These results provide new evidence that changes in task goals can result in qualitative differences in the way that identical visual stimuli are represented in WM. [ABSTRACT FROM AUTHOR]

Mild traumatic brain injuries (mTBIs) commonly occur in children and adolescents and can result in persistent cognitive symptoms. The neurophysiological changes that underlie persistent post-concussive symptoms (PPCS) have not been characterized. Our objective was to compare working-memory related functional magnetic resonance imaging (fMRI) response in children with persistent symptoms after mTBI at one month post-injury to children with typical recovery and healthy controls. This was a prospective, controlled cohort study of children with mTBI at one month post-injury. PPCS was defined as children with a 10-point increase in their post-concussion symptom inventory score (compared with pre-injury score) at one month post-injury and a two-point increase in at least two symptom categories compared with pre-injury. One hundred and seven participants (60 PPCS, 30 recovered mTBI, and 17 controls) with a mean age of 14.2 years (standard deviation [SD] 2.5) (44% male) were assessed 38 (SD 5.9) days after mTBI. The primary outcome measures were visuospatial n-back working memory task performance and fMRI blood oxygen level dependent (BOLD) signal change. Children with PPCS had decreased activation relative to children with typical recovery in the posterior cingulate and precuneus during the one-back working memory condition, despite similar task performance. Differences in cortical activation in children with PPCS at one month highlight the persistent neurobiological consequences of pediatric mTBI on working memory cortical activation. These findings encourage recommendations to avoid contact sports and provide continued care at school for children with persistent symptoms at one month post-injury. [ABSTRACT FROM AUTHOR]

Complex span and content-embedded tasks are two kinds of tasks that are designed to measure maintenance and processing in the working memory system. However, a key functional difference between these task types is that complex span tasks require the maintenance of information that is not relevant to the processing task, whereas content-embedded tasks require the maintenance of task-relevant information. The purpose of the present research was to test the hypothesis that more unique variance in inductive reasoning would be explained by content-embedded tasks than by complex span tasks, given that inductive reasoning requires reasoners to maintain and manipulate task-relevant information in order to arrive to a solution. A total of 384 participants completed three complex span tasks, three content-embedded tasks, and three inductive reasoning tasks. The primary structural equation model explained 51% of the variance in inductive reasoning; 45% of the variance in inductive reasoning was uniquely predicted by the content-embedded latent factor, 6% of the variance was predicted by shared variance between the content-embedded and complex span latent factors, and less than 1% was uniquely predicted by the complex span latent factor. These outcomes provide a novel extension to the small but growing literature showing an advantage of using content-embedded rather than complex span tasks for predicting higher-level cognition. [ABSTRACT FROM AUTHOR]