Working memory updating function training influenced brain activity

The near and far transfer effects of computerized working memory training in typically developing preschool children: Evidence from event-related potentials

Working memory (WM) refers to the ability to actively maintain and process information needed to complete complex tasks such as comprehension, learning, and reasoning. Recent studies have examined the efficacy of computerized working memory training (WMT) in improving cognitive functions in general and WM in particular, with mixed results. Thus, to what extent can WMT produce near and far transfer effects to cognitive function is currently unclear. This study investigated the transfer effects of a computerized WMT for preschool children and also examined the possible neural correlates using the event-related potential (ERP) technique. A total of 50 Chinese preschoolers (64.44 ± 7.76 months old; 24 girls) received 4-week training during school hours. Compared with those in the active control group, children in the training group showed better gains in behavioral performance in the WM task and significantly more changes in ERP markers of the WM and inhibitory control tasks (near transfer effect). However, no evidence was found for transfer to fluid intelligence (far transfer effect). These findings suggest that WMT is capable of enhancing cognitive functioning in preschool children, and as such this work has important implications for educational practice and it may help to design and refine cognitive interventions for typically developing children and those with WM problems or other cognitive deficits (e.g., children with attention-deficit/hyperactivity disorder).

Effects of computerized working memory training on neuroplasticity in healthy individuals: A combined neuroimaging and neurotransmitter study

Working memory (WM) is an essential cognitive function that underpins various higher-order cognitive processes. Improving WM capacity through targeted training interventions has emergered as a potential approach for enhancing cognitive abilities. The present study employed an 8-week regimen of computerized WM training (WMT) to investigate its effect on neuroplasticity in healthy individuals, utilizing neuroimaging data gathered both before and after the training. The key metrics assessed included the amplitude of low-frequency fluctuations (ALFF), voxel-based morphometry (VBM), and the spatial distribution correlations of neurotransmitter. The results indicated that post-training, compared to baseline, there was a reduction in ALFF in the medial superior frontal gyrus and an elevation in ALFF in the left middle occipital gyrus within the training group. In comparison to the control group, the training group also exhibited decreased ALFF in the anterior cingulate cortex, angular gyrus, and superior parietal lobule, along with increased ALFF in the postcentral gyrus post-training. VBM analysis revealed a significant increase in gray matter volume (GMV) in the right dorsal superior frontal gyrus after the training period, compared to the initial baseline measurement. Furthermore, the training group showed GMV increases in the dorsal superior frontal gyrus, Rolandic operculum, precentral gyrus, and postcentral gyrus when compared to the control group. In addition, significant associations were identifed between neuroimaging measurements (AFLL and VBM) and the spatial patterns of neurotransmitters such as serotonin (5-HT), dopamine (DA), and N-methyl-D-aspartate (NMDA), providing insights into the underlying neurochemical processes. These findings clarify the neuroplastic changes caused by WMT, offering a deeper understanding of brain plasticity and highlighting the potential advantages of cognitive training interventions.

Attention control training and transfer effects on cognitive tasks

Attention control is the common element underlying different executive functions. The backward Masking Majority Function Task (MFT-M) requires intensive attention control, and represents a diverse situation where attentional resources need to be allocated dynamically and flexibly to reduce uncertainty. Aiming to train attention control using MFT-M and examine the training transfer effects in various executive functions, we recruited healthy young adults (n = 84) and then equally randomized them into two groups trained with either MFT-M or a sham program for seven consecutive days. Cognitive evaluations were conducted before and after the training, and the electroencephalograph (EEG) signals were recorded for the revised Attention Network Test (ANT-R), N-back, and Task-switching (TS) tasks. Compared to the control group, the training group performed better on the congruent condition of Flanker and the double-congruency condition of Flanker and Location in the ANT-R task, and on the learning trials in the verbal memory test. The training group also showed a larger P2 amplitude decrease and P3 amplitude increase in the 2-back task and a larger P3 amplitude increase in the TS task's repeat condition than the control group, indicating improved neural efficiency in two tasks' attentional processes. Introversion moderated the transfer effects of training, as indicated by the significant group*introversion interactions on the post-training 1-back efficiency and TS switching cost. Our results suggested that attention control training with the MFT-M showed a broad transfer scope, and the transfer effect was influenced by the form of training task. Introversion facilitated the transfer to working memory and hindered the transfer to flexibility.

Long-term findings on working memory neural dynamics in healthcare workers after mild COVID-19

OBJECTIVE

Understanding the long-term impact of Coronavirus Disease 2019 (COVID-19) on cognitive function, even in mild cases, is critical to the well-being of individuals, especially for healthcare workers who are at increased risk of exposure to the virus. To the best of our knowledge, the electrophysiological activity underlying cognitive functioning has not yet been explored.

METHODS

Seventy-seven healthcare workers took part in the study (43 with mild infection about one year before the study and 34 uninfected). To assess cognitive status, event-related potentials (ERPs) and behavioural responses were recorded while participants performed a working memory task.

RESULTS

COVID-19 participants exhibited a distinct neural pattern with lower parieto-occipital N1 amplitudes and higher frontal P2 amplitudes as compared to non-infected healthcare workers. We found no behavioural differences (reaction times and error rates) in working memory functioning between groups.

CONCLUSIONS

This neural pattern suggests the presence of a decrement of processing resources linked to the encoding of sensory information (N1), followed by the enhanced of the P2 response which could be interpreted as the activation of compensation mechanism in COVID-19 participants.

SIGNIFICANCE

The current findings point out that ERPs could serve as valuable neural indices for detecting distinctive patterns in working memory functioning of COVID-19 participants, even in mild cases. However, further research is required to precisely ascertain the long-term cognitive effects of COVID-19 beyond one-year post-infection.

The effects of working memory training on attention deficit, adaptive and non-adaptive cognitive emotion regulation of Chinese children with Attention Deficit/Hyperactivity Disorder (ADHD)

BACKGROUND

Attention Deficit/Hyperactivity Disorder (ADHD) poses cognitive and emotional challenges for Chinese children. This study addresses the potential benefits of Working Memory Training for ADHD-affected children. Understanding its impact on Attention, cognitive regulation, and emotional responses is crucial for tailored interventions in the Chinese context. The Trial Registration Number (TRN) for this study is [TRN-2023-123,456], and it was officially registered on July 15, 2023, by Changchun Normal University.

OBJECTIVES

This study investigated how Working Memory training influences Attention, adaptive cognitive regulation, and non-adaptive cognitive emotion regulation in Chinese children with ADHD. It also assessed changes in attentional focus, improvements in adaptive cognitive regulation, and alterations in non-adaptive cognitive emotion regulation strategies.

METHODOLOGY

This quasi-experimental study aimed to assess the impact of working memory training on Chinese children with ADHD. Using pretest-posttest measures, 120 female students underwent Cogmed software training, targeting attention deficits and cognitive emotion regulation. Three reliable instruments measured outcomes. The procedure involved informed consent, questionnaires, 25 training sessions, and a two-month follow-up. Statistical analyses, including repeated measures ANOVA, assessed training effects.

RESULTS

ANOVA revealed a significant impact of Working memory training on attention deficit. Repeated measures ANOVA for cognitive emotion regulation indicated positive changes in adaptive and non-adaptive strategies over time, with sustained improvements in self-blame, rumination, catastrophizing, and blaming others. Bonferroni follow-up tests showed significant differences between pre-test, post-test, and follow-up, favoring the post-test and follow-up tests.

CONCLUSIONS

In summary, this research sheds light on the positive impact of memory training on Attention and cognitive emotion regulation in children with ADHD. The study underscores the potential of working memory interventions, particularly software-focused approaches, in enhancing attention levels and improving cognitive emotion regulation. The findings align with existing literature emphasizing the role of working memory deficits in ADHD.

IMPLICATIONS

Practically, incorporating memory training interventions into educational settings emerges as a viable strategy to support children with ADHD. This includes integrating memory training programs into both classroom activities and home-based interventions. Additionally, sustained implementation and long-term follow-up assessments are crucial for maximizing the effectiveness of memory training interventions. Tailoring interventions to specific ADHD subtypes and seamlessly integrating memory training activities into daily routines offer practical and personalized solutions for managing ADHD symptoms in diverse settings.

Successful alpha neurofeedback training enhances working memory updating and event-related potential activity

Neurofeedback (NF) is a promising method to self-regulate human brain activity for cognition enhancement. Due to the unclear results of alpha NF training on working memory updating as well as the impact of feedback modality on NF learning, this study aimed to understand further the underlying neural mechanism of alpha NF training effects on working memory updating, where the NF learning was also compared between visual and auditory feedback modalities. A total of 30 participants were assigned to Visual NF, Auditory NF, and Control groups. Working memory updating was evaluated by n-back (n =2,3) tasks before and after five alpha upregulation NF sessions. The result showed no significant difference in NF learning performance between the Visual and Auditory groups, indicating that the difference in feedback modality did not affect NF learning. In addition, compared to the control group, the participants who achieved successful NF learning showed a significant increase in n-back behavioral performance and P3a amplitude in 2-back and a significant decrease in P3a latency in 3-back. Our results in n-back further suggested that successful alpha NF training might improve updating performance in terms of the behavioral and related event-related potential (ERP) measures. These findings contribute to the understanding of the effect of alpha training on memory updating and the design of NF experimental protocol in terms of feedback modality selection.

The influence of cognitive ability in Chinese reading comprehension: can working memory updating change Chinese primary school students' reading comprehension performance?

With the development of educational cognitive neuroscience, language instruction is no longer perceived as mechanical teaching and learning. Individual cognitive proficiency has been found to play a crucial role in language acquisition, particularly in the realm of reading comprehension. The primary objective of this study was to investigate two key aspects: firstly, to assess the predictive effects of the central executive (CE) on the Chinese reading comprehension scores of Chinese primary school students, and secondly, to explore the influence of CE training on the Chinese reading comprehension performance of Chinese primary school students. Chinese primary school students were recruited as participants. Experiment 1 used a Chinese N-back task, a Chinese Stroop task, and a number-pinyin conversion task to investigate the predictive effect of the CE components on Chinese reading comprehension. Experiment 2, based on the results of Experiment 1, used the Chinese character N-back training to explore the influence of updating training on Chinese reading comprehension. The findings from Experiment 1 underscored that CE had a predictive effect on Chinese reading comprehension scores. And updating had a prominent role in it. Experiment 2 revealed that the experimental group exhibited an enhancement in their updating performance following N-back training. Although the reading comprehension performance of the two groups after training did not produce significant differences in total scores, the experimental group showed maintained and higher microscopic reading comprehension scores than the control group in the more difficult post-test. In summary, this study yields two primary conclusions: (1) CE was able to predict Chinese reading comprehension scores. Updating has an important role in prediction. (2) Updating training enhances students' updating performance and positively influences students' Chinese microscopic reading comprehension performance.

Audiovisual n-Back Training Alters the Neural Processes of Working Memory and Audiovisual Integration: Evidence of Changes in ERPs

(1) Background: This study investigates whether audiovisual n-back training leads to training effects on working memory and transfer effects on perceptual processing. (2) Methods: Before and after training, the participants were tested using the audiovisual n-back task (1-, 2-, or 3-back), to detect training effects, and the audiovisual discrimination task, to detect transfer effects. (3) Results: For the training effect, the behavioral results show that training leads to greater accuracy and faster response times. Stronger training gains in accuracy and response time using 3- and 2-back tasks, compared to 1-back, were observed in the training group. Event-related potentials (ERPs) data revealed an enhancement of P300 in the frontal and central regions across all working memory levels after training. Training also led to the enhancement of N200 in the central region in the 3-back condition. For the transfer effect, greater audiovisual integration in the frontal and central regions during the post-test rather than pre-test was observed at an early stage (80-120 ms) in the training group. (4) Conclusion: Our findings provide evidence that audiovisual n-back training enhances neural processes underlying a working memory and demonstrate a positive influence of higher cognitive functions on lower cognitive functions.

The effect of working memory updating training on the Chinese writing ability of primary school students

Objective

This study aimed to explore the effects of working memory updating training on primary school students' writing ability and performance.

Methods

A total of 46 fourth-grade Chinese primary school students were recruited; their performance in the Chinese character N-back training task, the Writing Ability Questionnaire, and a time-limited writing task was assessed.

Results

The paired-sample t-test revealed that working memory updating training significantly improved the experimental group's working memory level. After training, a repeated measures ANOVA revealed that the experimental group's performance on the Writing Ability Questionnaire improved and was higher than that of the control group. In the time-limited writing task, independent-sample t-tests revealed that the experimental group's writing fluency increased and was higher than that of the control group, while the latter's grammatical accuracy and complexity decreased and were lower than those of the former.

Conclusion

Working memory updating training can be used as auxiliary cognitive training to improve primary school students' working memory level, thereby promoting their writing development.

Do executive functions buffer against COVID-19 stress?: A latent variable approach

Levels of COVID-19 stress have soared worldwide as a result of the pandemic. Given the pernicious psychological and physiological effects of stress, there is an urgent need for us to protect populations against the pandemic's psychological impact. While there exists literature documenting the prevalence of COVID-19 stress among various populations, insufficient research has investigated psychological factors that might mitigate this worrying trend. To address this gap in the literature, the current study seeks to examine executive functions as a potential cognitive buffer against COVID-19 stress. To do so, the study adopted a latent variable approach to examine three latent factors of executive functions and their relation to COVID-19 stress among a sample of 243 young adults. Structural equation models showed differential associations between COVID-19 stress and the latent factors of executive functions. While the latent factor of updating working memory was associated with attenuated COVID-19 stress, task switching and inhibitory control were not significantly associated with COVID-19 stress. These results further our understanding of the critical processes of executive functions and highlight the nuanced link between executive functions and pandemic-related stress.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12144-023-04652-8.

Working memory dysfunction in fibromyalgia is associated with genotypes of the catechol- O-methyltransferase gene: an event-related potential study

Recent findings have associated different COMT genotypes with working memory capacity in patients with fibromyalgia. Although it is thought that the COMT gene may influence neural correlates (P2 and P3 ERP components) underlying working memory impairment in this chronic-pain syndrome, it has not yet been explored. Therefore, the aim of the present research was to investigate the potential effect of the COMT gene in fibromyalgia patients on ERP working memory indices (P2 and P3 components). For this purpose, 102 participants (51 patients and 51 healthy control participants) took part in the experiment. Event-related potentials and behavioral responses were recorded while participants performed a spatial n-back task. Participants had to decide if the stimulus coincided or not in the same location as the one presented one (1-back condition) or two (2-back condition) trials before. Genotypes of the COMT gene were determined through a saliva sample from all participants. Present results significantly showed lower working memory performance (p < 0.05) in patients with fibromyalgia as compared to control participants (higher rate of errors and slower reaction times). At neural level, we found that patients exhibited enhanced frontocentral and parieto-occipital P2 amplitudes compared to control participants (p < 0.05). Interestingly, we also observed that only fibromyalgia patients carrying the Val/Val genotype of the COMT gene showed higher frontocentral P2 amplitudes than control participants (p < 0.05). Current results (behavioral outcomes and P2 amplitudes) confirmed the presence of an alteration in working memory functioning in fibromyalgia. The enhancement of frontocentral P2 could be reflecting that these patients would manifest an inefficient way of activating executive attention processes, in carriers of the Val/Val genotype of COMT. To our knowledge, the present findings are the first linking neural indices of working memory dysfunctions and COMT genotypes in fibromyalgia. Applying a subgroup of patient's strategy based on this genetic marker could be useful to establish more tailored therapeutical approaches.

Sleep Deprivation-Induced Changes in Baseline Brain Activity and Vigilant Attention Performance

Sleep deprivation (SD) negatively affects several aspects of cognitive performance, and one of the most widely-used tools to evaluate these effects is the Psychomotor Vigilance Test (PVT). The present study investigated the possibility of predicting changes induced by SD in vigilant attention performance by evaluating the baseline electroencephalographic (EEG) activity immediately preceding the PVT stimuli onset. All participants (n = 10) underwent EEG recordings during 10 min of PVT before and after a night of SD. For each participant, the root mean square (RMS) of the baseline EEG signal was evaluated for each 1 s time window, and the respective average value was computed. After SD, participants showed slower (and less accurate) performance in the PVT task. Moreover, a close relationship between the changes in the baseline activity with those in cognitive performance was identified at several electrodes (Fp2, F7, F8, P3, T6, O1, Oz, O2), with the highest predictive power at the occipital derivations. These results indicate that vigilant attention impairments induced by SD can be predicted by the pre-stimulus baseline activity changes.

Repetitive Anodal TDCS to the Frontal Cortex Increases the P300 during Working Memory Processing

Transcranial direct current stimulation (TDCS) is a technique with which neuronal activity, and therefore potentially behavior, is modulated by applying weak electrical currents to the scalp. Application of TDCS to enhance working memory (WM) has shown promising but also contradictory results, and little emphasis has been placed on repeated stimulation protocols, in which effects are expected to be increased. We aimed to characterize potential behavioral and electrophysiological changes induced by TDCS during WM training and evaluate whether repetitive anodal TDCS has a greater modulatory impact on the processes underpinning WM than single-session stimulation. We examined the effects of single-session and repetitive anodal TDCS to the dorsolateral prefrontal cortex (DLPFC), targeting the frontal-parietal network, during a WM task in 20 healthy participants. TDCS had no significant impact on behavioral measures, including reaction time and accuracy. Analyzing the electrophysiological response, the P300 amplitude significantly increased following repetitive anodal TDCS, however, positively correlating with task performance. P300 changes were identified over the parietal cortex, which is known to engage with the frontal cortex during WM processing. These findings support the hypothesis that repetitive anodal TDCS modulates electrophysiological processes underlying WM.

EEG correlates of neutral working memory training induce attentional control improvements in test anxiety

Attentional control theory states that high test anxious (HTA) individuals suffer from impaired attentional control. However, through working memory training it may be possible to improve such individuals' attentional control ability. This study investigated whether 20 days of working memory training (with emotionally neutral stimuli) does result in improved HTA individuals' attentional control ability. Pre- and post-outcomes of attentional control were measured using Flanker and Go/Nogo experimental tasks in a test-related stress situation, and EEG data were also collected. Results only showed a significant decrease in Nogo alpha power in HTA individuals after neutral working memory training (i.e., post-outcome versus pre-outcome). However, we failed to provide evidence for beneficial transfer effects of neutral working memory training on enhanced task performance in both the Flanker and the Go/Nogo tasks. So, the present study demonstrates that neutral working memory training is clearly associated with important neurophysiological correlates while performing the Go/Nogo task, but the transfer effect is rather limited.

The effect of working memory capacity and training on intertemporal decision making in children from low-socioeconomic-status families

Individuals differ in their tendency to discount delayed rewards. Low socioeconomic status (SES) has been found to be associated with strong delayed reward discounting (DRD), which in turn contributes to risky decision making and adverse behaviors. However, research on possible cognitive mediators of the negative association between SES and DRD, and on effects of cognitive training in low-SES adolescents, is largely lacking. In examining Chinese adolescents (aged 11-15 years; N = 207), Study 1 assessed which aspect of working memory (WM)-simple maintenance, simple manipulation, or updating-serves as mediator, which proved to be WM updating. Based on this outcome, in Study 2 Chinese adolescents (aged 12-14 years; N = 73) with low family SES were assigned to a WM updating training condition or a control condition. All participants performed DRD and WM tasks before and after treatment. The trained adolescents showed positive training effects on DRD, and this effect was specifically correlated with beneficial training effects on performance on a WM updating transfer task. These results support the role of WM updating in DRD and might inform training programs to promote more favorable decision making in low-SES adolescents.

Event-related potentials associated to N-back test performance in schizophrenia

Mapping of Event-Related Potentials (ERP) associated with auditory and visual odd-ball paradigms has shown consistent differences between healthy controls and schizophrenia patients. It may be hypothesized that higher task attentional/cognitive demand will result in larger differences in these paradigms, which may help understanding the substrates of cognitive deficits in this syndrome. To this aim, we performed an EEG study comparing the effects of increasing the attentional/cognitive load of an auditory N-back task on the Event-Related Potential in 50 subjects with schizophrenia (11 first episodes) and 35 healthy controls. We considered a post-target window of 1000 ms to explore possible between groups differences in N100, P300, and Late Slow Wave (LSW), and compared these components between 0-back ('lower attentional/cognitive load) and 1-back ('higher attentional/cognitive load') conditions. Our results showed that N100 and LSW amplitude increase from 0- to 1-back condition was significantly larger in healthy controls compared to schizophrenia patients. Furthermore, LSW amplitude difference between 0- and 1-back conditions positively correlated with performance in the behavioral cognitive assessment. Taken together, these results support that higher task attentional/cognitive load (0-back vs. 1-back condition) increase N100 amplitude differences and reveal new findings related to the LSW component in schizophrenia.

The effects of working memory training in children revealed by behavioral responses and ERP

BACKGROUND

Recent studies have examined the effect of computerized cognitive training on working memory (WM), but the behavioral and neural effects were uncertain. Also, few studies have explored WM training effects on children using event-related potentials. The purpose of our study was to investigate the effects of WM training in children, including the effects on behavioral performance and neurophysiological outcomes.

METHODS

Forty-four healthy children (mean age = 7.76 years, SD = 0.57 years, 18 females) were assigned to the training and control groups. Over 20 training sessions, the training group participated in the computation-span and spatial N-back tasks, whereas the control group joined in normal class activities. They all completed the pre- and post-test evaluation of WM tasks (digit span backwards task and N-back task).

RESULTS

The results showed that WM training led to improved performance in the digit span backwards task and 2-back task of post-test evaluation, shortened P3a and P3b latencies in nontarget trials during the spatial 1-back task, shortened P3a latency in target and nontarget trials, as well as increased P3b amplitude and shortened P3b latency in target trials during the spatial 2-back task.

CONCLUSIONS

These results suggested that WM training might enhance children's behavioral performance on WM tasks and brought about neurophysiological changes. This study gives insights into the potential of WM training effects on children's behavioral performance and neurophysiological outcomes.

Psychological and Electrophysiological Correlates of Word Learning Success

Background

A rich vocabulary supports human achievements in socio-economic activities, education, and communication. It is therefore important to clarify the nature of language acquisition as a complex multidimensional process. However, both the psychological and neurophysiological mechanisms underpinning language learning, as well as the links between them, are still poorly understood.

Objective

This study aims to explore the psychological and neurophysiological correlates of successful word acquisition in a person's native language.

Design

Thirty adults read sentences with novel nouns, following which the participants' electroencephalograms were recorded during a word-reading task. Event- related potentials in response to novel words and alpha oscillation parameters (amplitude, variability, and long-range temporal correlation dynamics) were analyzed. Learning outcomes were assessed at the lexical and semantic levels. Psychological variables measured using Amthauer's test (verbal abilities), BIS/BAS scales (motivation), and the MSTAT-1 (ambiguity tolerance) and alpha oscillation parameters were factored.

Results

Better recognition of novel words was related to two factors which had high factor loadings for all measured alpha oscillation parameters, indicating the role of attention networks and respective neural activity for enabling information processing. More successful learners had lower P200 amplitude, which also suggests higher attention-system involvement. Another factor predicted better acquisition of word meanings for less ambiguity-tolerant students, while the factor which pooled logical conceptual thinking ability and persistence in goal-reaching, positively correlated with acquisition of both word forms and meanings.

Conclusion

The psychological factors predominantly correlated with word-learning success in semantic tasks, while neurophysiological variables were linked to performance in the recognition task.

Working memory training improves emotion regulation in drug abstainers: Evidence from frontal alpha asymmetry

Drug addiction has been associated with unsuccessful emotion regulation, which can be improved by working memory training (WMT) in healthy populations. This study aimed to assess the effect of WMT on emotion regulation in drug abstainers. We divided 40 male drug abstainers into two groups: (i) the training group (n=20) participated in a running memory task for 20 days, and (ii) the control group (n=20) did not participate in any training task. We assessed the emotion regulation questionnaire (ERQ) and frontal electroencephalographic (EEG) activity while viewing pictures (including neutral, positive, negative and drug-related contents) for all participants before and after the training. After WMT for 20 days, the training group adopted more spontaneous emotion regulation strategies compared with control group. The asymmetry scores of training group improved while viewing negative and drug-related pictures compared to pretest, which suggests that they converted from right-brain asymmetry to left-brain asymmetry. However, the control group declined both in the ERQ scores and the asymmetry scores. These results suggest that WMT improves the emotion regulation of drug abstainers.

Electrophysiological correlates of the Categorization Working Memory Span task in older adults

Older adults typically show poor performance in tasks assessing working memory (WM), a crucial cognitive mechanism. The present study examined the electrophysiological correlates of a classic complex WM task often used in studies involving older adults, the Categorization Working Memory Span task (CWMS), by means of event-related potentials. Thirty-five healthy, right-handed older adults (64-75 years) were presented the CWMS task while a 38-channel EEG was measured, and the N1, P1, and word recognition potential (RP) were analyzed on four regions of interest (ROIs) of 5 electrodes each. Additionally, late positive components (P200 and P300) were analyzed in midline ROIs of 3 electrodes each. Participants also executed an n-back task (2-back condition) and an objective performance-based task (the Ability to solve Problems in Everyday life [APE]). At a behavioral level, significant correlations were found between the CWMS, the 2-back, and the APE tests. At a physiological level, N1 and word RP showed greater bilateral amplitude in posterior electrodes, but the better the CWMS and the 2-back performance, the greater the RP amplitude on posterior left sites. The CWMS task induced a clear P200 component, but its amplitude was not correlated with participants' behavioral performance. Altogether, notwithstanding that the bilateral RP pattern elicited by the CWMS is a clear marker of WM processing in older adults, better elderly performers on this complex WM test showed greater left hemisphere dominance to the automatic word RP.

Training Positive Rumination in Expressive Writing to Enhance Psychological Adjustment and Working Memory Updating for Maladaptive Ruminators

Rumination is associated with psychological adjustment and working memory (WM) capacity. Studies have shown that psychological interventions can reduce negative rumination and improve psychological adjustment and WM capacity. The present study investigated the effect of positive rumination training in expressive writing on psychological adjustment and WM updating capacity. Within an experimental design, positive rumination was manipulated for 10 participants who were maladaptive ruminators in an experiment using a 5-week training compared to the control group with nine participants. Results revealed significant enhancement of psychological adjustment and the response time (RT) of WM updating in the experimental group but not in the control group. The two groups did not show significant difference of all the variables in pretest. However, the experimental group showed significantly better outcomes than the control group in posttest. The results suggest that positive rumination training in expressive writing is effective and rumination has a causal influence on WM updating capacity.

Effects of working memory training on emotion regulation: Transdiagnostic review

Working memory training is widely used transdiagnostically to improve cognition. However, more recently, studies using working memory training packages have targeted emotion-regulation outcomes to determine whether far transfer effects can be achieved. A narrative review is conducted of studies that have used standardized computerized working memory training packages across healthy volunteers, affect, anxiety, post-traumatic stress disorder (PTSD), and eating disordered populations with emotion-regulation outcomes. Working memory training has been used in children, adolescents, and adults to improve emotion regulation. Many studies have reported gains in mood as well as emotion-regulation strategies following working memory training, regardless of clinical indication and whether near transfer gains were achieved in cognitive domains. Significant emotion-regulation outcomes include: state and trait anxiety, rumination, brooding, positive appraisal, decreasing maladaptive emotion-regulation strategies, and decreasing intrusive thoughts. It is speculated that these far transfer outcomes from working memory training are possible due to the cognitive and neural overlap between cognitive and affective working memory, and emotion regulation. Working memory training could improve cognitive efficiency, which, in turn, increases the availability of cognitive resources during times when emotion regulation is taxed. Future studies need to consider the role of participant expectancy in predicting outcome measure performance, and including subjective and objective outcomes is paramount to study design. Furthermore, sample sizes require additional attention, given that the current review highlights that individual differences in non-clinical and clinical populations influence the outcomes from working memory training. Working memory training offers a possibility for improving emotion regulation transdiagnostically.

False memory production in schizophrenia: A neurophysiological investigation

Background

The topic of false memory in schizophrenia has been well documented in earlier research contributions. To date, there is no study exploring the implications of specific neural networks during this phenomenon in patients suffering from schizophrenia.

Methods

We compared 17 patients suffering from psychosis (SCZ) to 33 healthy controls (HC) performing a verbal memory task designed to produce false memories, i.e. the Deese-Roediger-McDermott paradigm (DRM). Electroencephalography was used to specifically analyze the P2 and N400 event-related potentials components.

Results

The SCZ patients showed a reduced ability to distinguish between true and false memories as assessed by the A' index which was calculated based on the false and true memory rates. The morphology of the P2 differed in frontal electrode region with a lower amplitude in SCZ. In addition, the amplitude of N400 was more pronounced (more negative) in HC than in SCZ in centro-parietal electrode site.

Conclusions

We suggest that the differences found in P2 amplitude are associated with difficulties of SCZ patients to efficiently compare item-specific features of a mnesic elements to incoming stimuli which impair the subsequent verbal memory information processing reflected by the N400 component amplitude decrease. These results are consistent with the idea that SCZ use a different strategy while they perform the DRM paradigm.

The Neuro Patterns Prior to Error Responses in Long-Lasting Working Memory Task: An Event-Related Potential Study

Few studies exist regarding the mechanism prior to response by which cognitive impairment may induce error in a single long-lasting task. The present study intends to clarify the changes in cognition at the electrophysiological level. Changes in amplitude and latency of N1, P2, N2, and P3 components of event-related potentials (ERPs) were analyzed for error and correct trials during normal and fatigue. Twenty-nine participants had to perform a 2-back working memory (WM) task for 100 min. The first 10 min and the last 10 min of the task were used as the normal state and fatigue state of the participant, respectively. EEG data were obtained from the first 10-min period and the final 10-min period. The results revealed smaller P3 and P2 amplitudes and longer P2 and N2 latency in the final 10-min which was after a long-lasting time task. Moreover, smaller P3 and P2 amplitudes but larger N2 amplitudes were observed in error trials for both states. Our results indicated that: (1) long lasting involvement in a cognitive task had a detrimental effect on attention, memory updating and cognitive control; and (2) impaired attention, impairments in memory updating and cognitive control were related to task errors. Our results imply that several impaired cognitive processes were consistently associated with the error and the altered ERP represents the neural patterns prior to error response in mental fatigue state.

Neuronal diversity and reciprocal connectivity between the vertebrate hippocampus and septum

A hallmark of the nervous system is the precision with which myriad cell types are integrated into functional networks that control complex behaviors. The limbic system governs evolutionarily conserved processes essential for survival. The septum and the hippocampus are central to the limbic system, and control not only emotion-related behaviors but also learning and memory. Here, we provide a developmental and evolutionary perspective of the hippocampus and septum and highlight the neuronal diversity and circuitry that connects these two central components of the limbic system. This article is categorized under: Nervous System Development > Vertebrates: Regional Development Nervous System Development > Vertebrates: General Principles Comparative Development and Evolution > Regulation of Organ Diversity.

Behavioural and electrophysiological modulations induced by transcranial direct current stimulation in healthy elderly and Alzheimer's disease patients: A pilot study

OBJECTIVE

To investigate whether anodal and cathodal transcranial direct current stimulation (tDCS) can modify cognitive performance and neural activity in healthy elderly and Alzheimer's disease (AD) patients.

METHODS

Fourteen healthy elderly and twelve AD patients performed a working memory task during an electroencephalogram recording before and after receiving anodal, cathodal, and sham tDCS over the left dorsolateral prefrontal cortex. Behavioural performance, event-related potentials (P200, P300) and evoked cortical oscillations were studied as correlates of working memory.

RESULTS

Anodal tDCS increased P200 and P300 amplitudes in healthy elderly. Cathodal tDCS increased P200 amplitude and frontal theta activity between 150 and 300 ms in AD patients. Improved working memory after anodal tDCS correlated with increased P300 in healthy elderly. In AD patients, slight tendencies between enhanced working memory and increased P200 after cathodal tDCS were observed.

CONCLUSIONS

Functional neural modulations were promoted by anodal tDCS in healthy elderly and by cathodal tDCS in AD patients.

SIGNIFICANCE

Interaction between tDCS polarity and the neural state (e.g., hyper-excitability exhibited by AD patients) suggests that appropriate tDCS parameters (in terms of tDCS polarity) to induce behavioural improvements should be chosen based on the participant's characteristics. Future studies using higher sample sizes should confirm and extend the present findings.

Distinguishing the Visual Working Memory Training and Practice Effects by the Effective Connectivity During n-back Tasks: A DCM of ERP Study

Visual working memory (WM) training and practice can result in improved task performance and increased P300 amplitude; however, only training can yield N160 enhancements. N160 amplitudes are related to the spatial attention, the detection of novelty and the inhibitory control, while P300 amplitudes are related to the selective attention. Therefore, it could be speculated that the mechanisms underlying N160 and P300 production may differ to accommodate to their functions. Based on the different N160 engagements and different functional roles of N160 and P300, we hypothesized that the effects of visual WM training and practice can be dissociated by their brain effective connectivity patterns. We compared different neural connectivity configurations for the main task-related brain activities including N160 and P300 during the visual three-back task in subjects after visual WM training (the WM group) and after repetitive task practice (the control group). The behavioral result shows significantly greater improvement in accuracy after training and suggests that visual WM training can boost the learning process of this simple task. The N160 peak amplitude increased significantly after training over the anterior and posterior brain areas but decreased after practice over the posterior areas, indicating different mechanisms for mediating the training and practice effects. In support of our hypothesis, we observed that visual WM training alters the frontal-parietal connections, which comprise the executive control network (ECN) and the dorsal attention network (DAN), whereas practice modulates the parietal-frontal connections underpinning P300 production for selective attention. It should be noted that the analytic results in this study are conditional on the plausible models being tested and the experimental settings. Studies that employ different tasks, devices and plausible models may lead to different results. Nevertheless, our findings provide a reference for distinguishing the visual WM training and practice effects by the underlying neuroplasticity.

Skipping Breakfast Affects the Early Steps of Cognitive Processing

Abstract. It has been generally accepted that skipping breakfast adversely affects cognition, mainly disturbing the attentional processes. However, the effects of short-term fasting upon brain functioning are still unclear. We aimed to evaluate the effect of skipping breakfast on cognitive processing by studying the electrical brain activity of young healthy individuals while performing several working memory tasks. Accordingly, the behavioral results and event-related brain potentials (ERPs) of 20 healthy university students (10 males) were obtained and compared through analysis of variances (ANOVAs), during the performance of three n-back working memory (WM) tasks in two morning sessions on both normal (after breakfast) and 12-hour fasting conditions. Significantly fewer correct responses were achieved during fasting, mainly affecting the higher WM load task. In addition, there were prolonged reaction times with increased task difficulty, regardless of breakfast intake. ERP showed a significant voltage decrement for N200 and P300 during fasting, while the amplitude of P200 notably increased. The results suggest skipping breakfast disturbs earlier cognitive processing steps, particularly attention allocation, early decoding in working memory, and stimulus evaluation, and this effect increases with task difficulty.

Cognition Impairment Prior to Errors of Working Memory Based on Event-Related Potential

Cognitive impairment contributes to errors in different tasks. Poor attention and poor cognitive control are the two neural mechanisms for performance errors. A few studies have been conducted on the error mechanism of working memory. It is unclear whether the changes in memory updating, attention, and cognitive control can cause errors and, if so, whether they can be probed at the same time in one single task. Therefore, this study analyzed event-related potentials in a two-back working memory task. A total of 40 male participants finished the task. The differences between the error and the correct trials in amplitudes and latencies of N1, P2, N2, and P3 were analyzed. The P2 and P3 amplitudes decreased significantly in the error trials, while the N2 amplitude increased. The results showed that impaired attention, poor memory updating, and impaired cognitive control were consistently associated with the error in working memory. Furthermore, the results suggested that monitoring the neurophysiological characteristics associated with attention and cognitive control was important for studying the error mechanism and error prediction. The results also suggested that the P3 and N2 amplitudes could be used as indexes for error foreshadowing.

Distress intolerance modulation of neurophysiological markers of cognitive control during a complex go/no-go task

Distress intolerance (DI), a trait-like individual difference reflective of the inability to endure aversive affective states, is relevant to multiple forms of psychopathology, but its relations to theoretically relevant neurobiological systems have received little attention. Altered cognitive control-related neurobiology has been theorized to underlie individual differences in DI, but little empirical work has been conducted. To test this hypothesis, baseline data from a large community sample with elevated high levels of emotional psychopathology and comorbidity was utilized (N = 256). Participants completed a complex go/no-go task while EEG was recorded, and P2, N2, and P3 amplitudes were measured. Based upon prior findings on the relations between these components and response inhibition, a core cognitive control function, we hypothesized that DI would predict reduced no-go N2 and P3 amplitude while controlling for current anxious/depressive symptom severity (i.e., negative affect). Peak amplitudes from the raw data and principal components analysis were used to quantify amplitude of ERP components. Partially consistent with predictions, high DI was independently associated with reduced no-go N2 peak amplitude in the raw ERP data, and was significantly related to a frontal positivity factor in the N2 time window across no-go and go trials. Contrary to predictions, no relations between DI and the P3 were found. Overall, results support the theorized relevance of cognitive control-linked neurobiology to individual differences in tolerance of distress over and above distress severity itself, and suggest specific relations between DI and alterations in early controlled attention/conflict-monitoring but not response inhibition or response inhibition-related sequelae. (PsycINFO Database Record

Individual differences in working memory and general intelligence indexed by P200 and P300: A latent variable model

A robust relationship between working memory (WM) and general intelligence (g) has been well established. Nevertheless, explanations for this relationship in terms of underlying neurocognitive processes are still inadequate. This study addresses this issue using an individual differences approach in which Central Executive System (CES) and Short-Term Storage (STS) components of WM are measured comprehensively and examined for their relationship with g via event-related potentials components (P200 and P300) as mediators. Participants (n = 115) completed tests of the WM, CES and STS, as well as g. P200 and P300 components were recorded during 3-back WM task performance. Structural equation modelling showed significant negative associations between the P200 latency for target stimuli and CES shifting processes, and between the P300 amplitude for target stimuli and CES inhibition and updating processes. The relationship between CES processes and g was mediated in a localized fashion by the P300 amplitude. These findings further support the notion that the CES has a multidimensional structure and, importantly, reveal that the inhibition and updating functions of the CES are crucial in explaining the relationship between WM and g. Negative relations between ERP indices (P200 latency and P300 amplitude for target stimuli) and g support a neural efficiency hypothesis related to high intelligence.

Working Memory Training Improves Emotion Regulation Ability

Emotion regulation deficits are associated with various emotional disorders. Therefore, studies have attempted to improve emotion regulation ability to prevent psychopathological symptoms. Studies have revealed that working memory training—specifically attention control—can promote emotion regulation. In the present study, participants completed a running memory task in a 20-day training period. The participants’ pre- and post-test data on attention network functions and late positive potential (LPP) were assessed and analyzed. Compared with the control group, the training group’s orientation function improved markedly. In addition, LPP in relation to emotion regulation decreased during the 20-day training period. These results suggest that working memory training can improve emotion regulation ability, and the orientation function in the attention network may also contribute to this improvement.

An event-related potential study of spatial working memory in binge drinking college students

This study used event-related potentials (ERPs) and a modified spatial 2-back task to investigate spatial working memory in binge drinking (BD) college students. Based on the Korean version of the Alcohol Use Disorder Identification Test (AUDIT-K) and Alcohol Use Questionnaire (AUQ) scores, participants were assigned into BD (n = 25) and non-BD (n = 25) groups. The modified spatial 2-back task includes congruent, incongruent, and lure conditions and participants are required to respond as rapidly and accurately as possible to the congruent stimuli but not to the incongruent and lure stimuli. The BD and non-BD groups exhibited comparable performances on the spatial 2-back task but the BD group showed significantly larger P3 amplitudes than the non-BD group. Additionally, the non-BD group showed larger P3 amplitudes in response to the congruent stimuli compared to the incongruent and lure stimuli whereas the P3 amplitudes in the BD group did not differ significantly among the three conditions. These results indicate that the BD individuals exerted greater effort to maintain performance levels comparable to non-BD individuals and that they were less efficient in differentiating or allocating attentional resources between relevant and irrelevant information.

Working Memory Updating Training Improves Mathematics Performance in Middle School Students With Learning Difficulties

Working memory (WM) deficit is considered the key cause of learning difficulties (LDs). Studies have shown that WM is plastic and thus can be improved through training. This positive effect is transferable to fluid intelligence and academic performance. This study investigated whether WM updating ability and academic performance in children with LDs could be improved through WM updating training and explored the effects of this training on the children’s brain activity. We used a running memory task lasting approximately 40 min per day for 28 days to train a group of 23 children with LDs (TLDs group). We also selected two control groups of 22 children with LDs (CLDs group) and 20 children without LDs (normal control [NC] group). The behavioral results of a pretest indicated that WM updating ability and academic performance in the TLDs and CLDs groups were significantly lower than those in the NC group before training. Compared with the CLDs group, the TLDs group exhibited significant performance improvement in a 2-back WM task, as well as in mathematical ability. Event-related potentials (ERPs) results suggested that the amplitudes of N160 (representative of visual recognition) and P300 (representative of updating processing, which is a valid index for updating WM) in the TLDs and CLDs groups were markedly lower than those in the NC group before training. In the TLDs group, these two components increased considerably after training, approaching levels similar to those in the NC group. The results of this study suggest that WM updating training can improve WM updating ability in children with LDs and the training effect can transfer to mathematical performance in such children. Furthermore, the participants’ brain activity levels can exhibit positive changes. This article provides experimental evidence that WM updating training could mitigate the symptoms of LDs to a certain degree.

The Benefits of Working Memory Capacity on Attentional Control under Pressure

The present study aimed to examine the effects of working memory capacity (WMC) and state anxiety (SA) on attentional control. WMC was manipulated by (a) dividing participants into low- and high-WMC groups (Experiment 1), and (b) using working memory training to improve WMC (Experiment 2). SA was manipulated by creating low- and high-SA conditions. Attentional control was evaluated by using antisaccade task. Results demonstrated that (a) higher WMC indicated better attentional control (Experiments 1 and 2); (b) the effects of SA on attentional control were inconsistent because SA impaired attentional control in Experiment 1, but favored attentional control in Experiment 2; and (c) the interaction of SA and WMC was not significant (Experiments 1 and 2). This study directly manipulated WMC by working memory training, which provided more reliable evidence for controlled attention view of WMC and new supportive evidence for working memory training (i.e., far transfer effect on attentional control). And the refinement of the relationship between anxiety and attentional control proposed by Attentional Control Theory was also discussed.

Effect of Working Memory Updating Training on Retrieving Symptoms of Children With Learning Disabilities

Working memory (WM) deficiency is a primary reason for the poor academic performance of children with learning disabilities (LDs). Studies have shown that the WM of typical children could be improved through training, and WM training contributes to improving their fluid intelligence and academic achievement. However, few studies have investigated WM training for children with LDs, and results have been inconsistent. The present study examined the long-term effects of WM updating training and whether it can mitigate LD symptoms. Fifty-four children with LDs were recruited and divided randomly into a training or control group. The training group underwent adaptive running WM training for 20 days. Before and after training, the 2 groups completed a 2-back task, a digit span task (forward and backward), Raven's Standard Progressive Matrices test, and a scholastic attainment test (Chinese and math). The tests were repeated 6 months later. The results showed that, as compared with the controls, the training group exhibited significant improvements in the digit backward span task, 2-back task, and Raven's Standard Progressive Matrices. The math scores of the training group improved significantly by 6 months after the training. The results of this study suggest that WM updating training could mitigate the cognitive deficits of LDs and improve the WM capacity, fluid intelligence, and math scores of children with LDs. Moreover, the training effects could be maintained for at least 6 months.

Functional brain organization of working memory in adolescents varies in relation to family income and academic achievement

Working memory (WM) capacity reflects executive functions associated with performance on a wide range of cognitive tasks and education outcomes, including mathematics achievement, and is associated with dorsolateral prefrontal and parietal cortices. Here we asked if family income is associated with variation in the functional brain organization of WM capacity among adolescents, and whether that variation is associated with performance on a statewide test of academic achievement in mathematics. Participants were classified into higher-income and lower-income groups based on family income, and performed a WM task with a parametric manipulation of WM load (N-back task) during functional magnetic resonance imaging (fMRI). Behaviorally, the higher-income group had greater WM capacity and higher mathematics achievement scores. Neurally, the higher-income group showed greater activation as a function of WM load in bilateral prefrontal, parietal, and other regions, although the lower-income group exhibited greater activation at the lowest load. Both groups exhibited positive correlations between parietal activations and mathematics achievement scores, but only the higher-income group exhibited a positive correlation between prefrontal activations and mathematics scores. Most of these findings were maintained when higher- and lower-income groups were matched on WM task performance or nonverbal IQ. Findings indicate that the functional neural architecture of WM varies with family income and is associated with education measures of mathematics achievement.

Brain enhancement through cognitive training: a new insight from brain connectome

Owing to the recent advances in neurotechnology and the progress in understanding of brain cognitive functions, improvements of cognitive performance or acceleration of learning process with brain enhancement systems is not out of our reach anymore, on the contrary, it is a tangible target of contemporary research. Although a variety of approaches have been proposed, we will mainly focus on cognitive training interventions, in which learners repeatedly perform cognitive tasks to improve their cognitive abilities. In this review article, we propose that the learning process during the cognitive training can be facilitated by an assistive system monitoring cognitive workloads using electroencephalography (EEG) biomarkers, and the brain connectome approach can provide additional valuable biomarkers for facilitating leaners' learning processes. For the purpose, we will introduce studies on the cognitive training interventions, EEG biomarkers for cognitive workload, and human brain connectome. As cognitive overload and mental fatigue would reduce or even eliminate gains of cognitive training interventions, a real-time monitoring of cognitive workload can facilitate the learning process by flexibly adjusting difficulty levels of the training task. Moreover, cognitive training interventions should have effects on brain sub-networks, not on a single brain region, and graph theoretical network metrics quantifying topological architecture of the brain network can differentiate with respect to individual cognitive states as well as to different individuals' cognitive abilities, suggesting that the connectome is a valuable approach for tracking the learning progress. Although only a few studies have exploited the connectome approach for studying alterations of the brain network induced by cognitive training interventions so far, we believe that it would be a useful technique for capturing improvements of cognitive functions.