Verbal Working Memory Research Articles

Can human brain connectivity explain verbal working memory?

ABSTRACT The ability of humans to store spoken words in verbal working memory and build extensive vocabularies is believed to stem from evolutionary changes in cortical connectivity across primate species. However, the underlying neurobiological mechanisms remain unclear. Why can humans acquire vast vocabularies, while non-human primates cannot? This study addresses this question using brain-constrained neural networks that realize between-species differences in cortical connectivity. It investigates how these structural differences support the formation of neural representations for spoken words and the emergence of verbal working memory, crucial for human vocabulary building. We develop comparative models of frontotemporal and occipital cortices, reflecting human and non-human primate neuroanatomy. Using meanfield and spiking neural networks, we simulate auditory word recognition and examine verbal working memory function. The “human models”, characterized by denser inter-area connectivity in core language areas, produced larger cell assemblies than the “monkey models”, with specific topographies reflecting semantic properties of the represented words. Crucially, longer-lasting reverberant neural activity was observed in human versus monkey architectures, compatible with robust verbal working memory, a necessary condition for vocabulary building. Our findings offer insights into the structural basis of human-specific symbol learning and verbal working memory, shedding light on humans’ unique capacity for large vocabulary acquisition.

Effectiveness of an Executive Functions Parental Program in ADHD Children

Attention/Deficit Hyperactivity Disorder (ADHD) is one of the most prevalent disorders in the child population. Evidence suggests that children with this disorder usually present impairments in executive functions (EF). This study aims to evaluate the effects of a home-based intervention applied by parents (Flii, A Space Adventure) on the EF of Brazilian children with ADHD. Sixteen children with ADHD aged 7 to 12 participated in this study. A battery of neuropsychological tests and questionnaires was applied as assessment. Afterwards, children’ received Flii programa applied at home by the parents. A relevant improvement in visuospatial working memory in the Flii group after the intervention (T2) compared to the control group. The results of the intragroup analyzes suggest that the intervention group had gains in processing speed, cognitive flexibility, verbal and visuospatial working memory. These results suggest that Flii was effective in promoting some changes in the children’ executive functioning.

Towards theoretically understanding how long-term memory semantics can support working memory performance.

Working memory is the system that supports the temporary storage and processing of information. It is generally agreed that working memory is a mental workspace, with a combination of resources operating together to maintain information in mind for potential use in thought and action. Theories typically acknowledge the contributions of long-term memory to this system. One particular aspect of long-term memory, namely semantic long-term memory, can effectively supplement or "boost" working memory performance. This may be a relatively automatic process via the semantic properties of the stimuli or more active via strategy development and implementation. However, the precise mechanisms require greater theoretical understanding. In this review of the literature, we critically discuss theoretical models of working memory and their proposed links with long-term memory. We also explore empirical research that contributes to our understanding of the ways in which semantics can support performance of both verbal and visuospatial working memory tasks, with a view to potential intervention development. This includes the possibility of training people with lower performance (e.g., older adults) to use semantics during working memory tasks. We conclude that semantics may offer an opportunity to maximise working memory performance. However, to realise this potential, more research is needed, particularly in the visuospatial domain.

EXPRESS: What are the benefits of directed attention within verbal working memory?

Information that is particularly relevant for upcoming behavior can be prioritized within working memory, by directing attention to it. Receiving focused attention during retention is assumed to be associated with specific benefits, such as increased memory performance and reduced vulnerability to perceptual distractions. This has been demonstrated in visuospatial working memory. Given the domain-general nature of the focus of attention, these benefits should extend to verbal working memory as well. This was tested in the current study. In particular, we examined and compared the effects of cue-based and reward-based prioritization in verbal working memory across a series of five preregistered experiments. These experiments varied in their memory materials, set size, interference, and memory task. Our results collectively revealed several key findings. Firstly, both cue-based and reward-based prioritization led to a clear and consistent memory boost for prioritized information in verbal working memory. Secondly, the memory boost induced by cue-based prioritization was mostly comparable to that induced by reward-based prioritization. Thirdly, memory for verbal information did not drastically suffer when exposed to perceptual interference. And lastly, the effect of perceptual interference on verbal information was not drastically influenced by whether the information was prioritized or not. Overall, this series of experiments contributes to understanding the consequences of directed attention in verbal working memory and highlights similarities and differences from findings in visuospatial working memory.

Exploring the Effect of Single-Session Transcranial Direct Current Stimulation on Attention, Verbal Fluency, and Working Memory in Patients With Alzheimer's Disease-Related Dementia.

Alzheimer's disease (AD) is a leading cause of morbidity and mortality among the elderly. Transcranial direct current stimulation (tDCS) applies low-intensity currents to the brain, resulting in short-term neurocognitive effects and long-term neuroplasticity enhancement. Limited research reported on the impact of tDCS on cognitive functions in dementia due to AD. This study aims to compare changes in verbal fluency and working memory following a single tDCS application to the left dorsolateral prefrontal cortex (DLPFC) in AD patients. Patients with mild dementia due to AD underwent cognitive assessment using the Standardized Mini-Mental Test, Clock Drawing Test, Rey Auditory Verbal Learning Test, Functional Activities Questionnaire, Informant Questionnaire on Cognitive Decline in the Elderly, and Montreal Cognitive Assessment Scale. A single-session tDCS was administered by applying anodal tDCS to the left DLPFC for a duration of 30 minutes. Verbal fluency and working memory were evaluated before and after tDCS using the WAIS-R Digit Span Test forward and backward subscales, Trail Making Test (TMT) A and B, and Verbal Fluency Test. Regarding cognitive test scores before and after tDCS application, there were statistically significant reductions in the durations of TMT-A and TMT-B. However, there were no significant differences observed for TMT B-A, VFT, DST-forward, and DST-backward performances. The findings indicate that a single anodal tDCS targeting the left DLPFC enhances attention and processing speed in AD patients but has no effect on working memory or verbal fluency.

Formal Thought Disorders and Neurocognition in Treatment-Resistant Schizophrenia: Trouble du cours de la pensée et neurocognition dans la schizophrénie réfractaire.

Formal thought disorders (FTDs), a core feature of schizophrenia, have been subdivided into positive and negative types, and are clinically assessed by examining speech (objective) or patient introspection (subjective). Despite being associated with poorer treatment response and worse outcomes, FTDs have been understudied in patients with schizophrenia, in particular treatment-resistant schizophrenia (TRS) or schizoaffective disorder. We aimed to explore the relationship between the severity of positive and negative FTDs and neurocognition as well as social/occupational functioning in this clinical subgroup. This was a retrospective chart review conducted at the Clozapine Clinic at the Centre for Addiction and Mental Health, Toronto, Canada. We reviewed charted standardized assessment of FTDs using the Thought and Language Disorder (TALD) scale, neurocognition using the Brief Cognitive Assessment Tool for Schizophrenia (B-CATS), and functioning using the Social and Occupational Functioning Assessment Scale (SOFAS) between October 2022 and June 2023. Following the original factor structure of the TALD, we computed 4- factor scores that combined positive or negative and objective or subjective FTDs. We then explored the correlation between the scores from each TALD factor and the neurocognition and functioning scores. We analysed data for 23 outpatients on clozapine. After the Bonferroni adjustment, total TALD scores, indicating overall severity of FTDs, were strongly and inversely correlated with SOFAS scores (p < 0.001). A strong inverse correlation was found between the objective positive TALD factor and Letter-Number Span verbal working memory scores, r(21) = -0.63, p < 0.001. Our results demonstrate the strong relationship between FTDs, neurocognition, and social/occupational functioning in a sample of TRS outpatients. Within the cognitive domains assessed, verbal working memory impairment had the strongest correlation with positive FTDs, such as derailment or tangentiality. These findings highlight the value of employing standardized psychopathological scales for FTDs in clinical practice.

A Functional Magnetic Resonance Imaging Study of Phrase Structure and Subject Island Violations.

In principle, functional neuroimaging provides uniquely informative data in addressing linguistic questions, because it can indicate distinct processes that are not apparent from behavioral data alone. This could involve adjudicating the source of unacceptability via the different patterns of elicited brain responses to different ungrammatical sentence types. However, it is difficult to interpret brain activations to syntactic violations. Such responses could reflect processes that have nothing intrinsically related to linguistic representations, such as domain-general executive function abilities. To facilitate the potential use of functional neuroimaging methods to identify the source of different syntactic violations, we conducted a functional magnetic resonance imaging experiment to identify the brain activation maps associated with two distinct syntactic violation types: phrase structure (created by inverting the order of two adjacent words within a sentence) and subject islands (created by extracting a wh-phrase out of an embedded subject). The comparison of these violations to control sentences surprisingly showed no indication of a generalized violation response, with almost completely divergent activation patterns. Phrase structure violations seemingly activated regions previously implicated in verbal working memory and structural complexity in sentence processing, whereas the subject islands appeared to activate regions previously implicated in conceptual-semantic processing, broadly defined. We review our findings in the context of previous research on syntactic and semantic violations using ERPs. Although our results suggest potentially distinct underlying mechanisms underlying phrase structure and subject island violations, our results are tentative and suggest important methodological considerations for future research in this area.

Focus on Executive Functions. Part 2: Nonverbal and Verbal Working Memory

The second in a 3-part series on executive functions. This series for adults with ADHD discusses the 7 executive functions that foster self-control—the abilities we use to monitor our own behavior to attain our goals. —Excerpted from Taking Charge of Adult ADHD (2nd ed.), by Russell A. Barkley with Christine M. Benton. Part 1: Self-awareness (the mind's mirror) and inhibition (the mind's brakes). Part 2: Nonverbal and verbal working memory (the mind’s eye and the mind’s voice). Part 3: Emotion regulation (the mind’s heart), self-motivation (the mind’s fuel tank), and planning/problem-solving (the mind’s playground).

Working memory related functional connectivity in adult ADHD and its amenability to training: A randomized controlled trial

BackgroundWorking memory (WM) deficits are among the most prominent cognitive impairments in attention deficit hyperactivity disorder (ADHD). While functional connectivity is a prevailing approach in brain imaging of ADHD, alterations in WM-related functional brain networks and their malleability by cognitive training are not well known. We examined whole-brain functional connectivity differences between adults with and without ADHD during n-back WM tasks and rest at pretest, as well as the effects of WM training on functional and structural brain connectivity in the ADHD group. MethodsForty-two adults with ADHD and 36 neurotypical controls performed visuospatial and verbal n-back tasks during functional magnetic resonance imaging (fMRI). In addition, seven-minute resting state fMRI data and diffusion-weighted MR images were collected from all participants. The adults with ADHD continued into a 5-week randomized controlled WM training trial (experimental group training on a dual n-back task, n = 21; active control group training on Bejeweled II video game, n = 21), followed by a posttraining MRI. Brain connectivity was examined with Network-Based Statistic. ResultsAt the pretest, adults with ADHD had decreased functional connectivity compared with the neurotypical controls during both n-back tasks in networks encompassing fronto-parietal, temporal, occipital, cerebellar, and subcortical brain regions. Furthermore, WM-related connectivity in widespread networks was associated with performance accuracy in a continuous performance test. Regarding resting state connectivity, no group differences or associations with task performance were observed. WM training did not modulate functional or structural connectivity compared with the active controls. ConclusionOur results indicate large-scale abnormalities in functional brain networks underlying deficits in verbal and visuospatial WM commonly faced in ADHD. Training-induced plasticity in these networks may be limited

Phonological skills and executive functions: their effects on reading and arithmetic abilities across varied performance levels using quantile regression

ABSTRACT We aimed to investigate the effects of phonological awareness – PA, rapid automatised naming – RAN, visuospatial and verbal working memory – WM and executive functions – EF on the reading and arithmetic skills of children with low- to medium-performance levels. Participants were 472 Brazilian children from 3rd to 5th grades. Quantile Regression Analysis was employed. The PA, RAN and EF were shared main predictors of both reading and math. Verbal WM emerged as a unique main predictor for reading, while visuospatial WM and visuospatial short-term memory were the main predictors for arithmetic. Among children with very low reading proficiency, the effects of cognitive predictors were more pronounced, a trend not observed in arithmetic. The results suggest varying magnitudes of cognitive predictors for reading when considering different levels of performance/difficulties. We also corroborate unique and shared main predictors of reading and math that have implications for research, clinical and educational settings.

The Role of Cognitive Learner Prerequisites for Cognitive Load and Learning Outcomes in AR-Supported Lab Work

Augmented Reality (AR) can enhance student-centered lab work by bridging the spatial and temporal split between virtual information and observed real-world phenomena. While the Cognitive Theory of Multimedia Learning and the Cognitive Load Theory suggest that AR can reduce extraneous cognitive load (ECL) and foster learning, the empirical results remain inconsistent. This re-analysis of three related studies with different target groups and AR devices explores whether learners’ spatial abilities and verbal working memory capacity moderate the effect of AR support in lab work settings on ECL and conceptual knowledge gains. Although these moderators could not be confirmed consistently, the results indicate that tablet-based AR holds the potential to support learners with low spatial abilities. Moreover, low verbal working memory learners were demonstrated to be particularly vulnerable to the spatial contiguity failure that can be caused by smartglasses AR. Moderation effects were only observed for ECL but not for conceptual knowledge gains. The findings highlight that the benefit of AR support can depend on learners’ cognitive prerequisites and additional contextual factors, such as the AR device used and the age of the target group. The design and implementation of AR-supported lab work environments should account for these factors to optimize the learning outcomes.

Improving cognitive function in Chinese children with ADHD and/or RD through computerized working memory training

BackgroundPrior research has found that children with attention-deficit hyperactivity disorder (ADHD) and reading difficulties (RD) are at an elevated risk of developing further cognitive deficits and developmental challenges [1]. ADHD and RD are characterized by a deficit in working memory, which negatively affects learning and behavior. The main aims of this study were to design a working memory training app and examine its effectiveness through a 5-week training program in Chinese children with ADHD and/or RD.MethodsThere were three experimental groups, with 26 participants in the ADHD group, 38 participants in the RD group, and 24 participants in the ADHD + RD group. The typically developing (TD) control group had 32 participants. All participants completed the pretest and posttest assessments on executive function and reading performance.ResultsThe findings indicate that the experimental groups improved performance in verbal and visual-spatial working memory as well as Chinese word reading. There was an overall reduction in functional impairment following the training, in contrast to the TD group.ConclusionThis study showed that working memory can be improved through computerized training in children with ADHD and/or RD. The implications of future research in working memory are discussed.Trial registrationClinical Trials Identifier: NCT06567444 (retrospectively registered) on 20 August 2024.

Predictors of sentence recall performance in children with and without DLD: Complexity matters.

Using archival data from 106 children with and without DLD who spoke two dialects of English, we examined the independent contributions of vocabulary, morphological ability, phonological short term memory (pSTM), and verbal working memory (WM) to exact sentence recall, ungrammatical repetition, and incorrect tense production. For exact repetitions on simpler sentences, performance of the DLD group was predicted by morphological ability, pSTM and WM, while that of the TD group was predicted by vocabulary and sometimes pSTM. On complex sentences, performance of the DLD group was predicted by morphological ability, and the TD group was predicted by pSTM and WM. For ungrammatical repetitions and incorrect tense, morphological ability was a factor for both groups, with WM also affecting the DLD group for ungrammatical production. Thus, sentence recall taxes multiple resources, with more and different factors being taxed at lower levels of complexity for children with DLD than those without.

Verbal and Spatial Working Memory Capacity in Blind Adults and the Possible Influence of Age at Blindness Onset: A Systematic Review and Meta-analysis.

The loss of a sense, such as vision, forces individuals to adapt to their environment and its demands in a variety of ways. In the case of blindness, significant neurofunctional and cognitive changes have been documented. However, there is no clear consensus on the differences in performance between adult blind participants and sighted controls in cognitive processes such as working memory (WM). Two variables are important, including the cognitive task used to measure working memory and the age at which vision loss occurs. This review is aimed at exploring potential disparities in verbal and spatial WM performance between blind and sighted adults, as well as understanding how these differences may be influenced by the age of vision loss. A systematic search across PsycArticles, PsycInfo, Medline, and Web of Science databases identified 21 pertinent studies. The studies were categorized, and effect sizes were calculated through meta-analysis, distinguishing between verbal (auditory simple forward and backward span, complex span, and n-back) and visuospatial WM tasks (adapted Corsi-block and simple storage tasks, imagery tasks, and complex storage tasks). Visual sensory loss induces adaptations affecting WM function in blind participants. In the verbal domain, improved phonological processing and/or serial item position encoding might facilitate WM retrieval. In contrast, in spatial WM, an over-reliance on serial processing may hinder strategic grouping in blind individuals. This review highlights the need to further explore the role of age at the time of vision loss. Although evidence suggests that adaptations to serial processing may be more pronounced in early development, particularly in comparison to those who become blind in adulthood, the available data are limited. The study calls for further research to deepen our understanding of cognitive adaptations and their temporal dynamics in response to vision loss.

An fMRI study of phrase structure and subject island violations.

In principle, functional neuroimaging provides uniquely informative data in addressing linguistic questions, because it can indicate distinct processes that are not apparent from behavioral data alone. This could involve adjudicating the source of unacceptability via the different patterns of elicited brain responses to different ungrammatical sentence types. However, it is difficult to interpret brain activations to syntactic violations. Such responses could reflect processes that have nothing intrinsically related to linguistic representations, such as domain-general executive function abilities. In order to facilitate the potential use of functional neuroimaging methods to identify the source of different syntactic violations, we conducted an fMRI experiment to identify the brain activation maps associated with two distinct syntactic violation types: phrase structure (created by inverting the order of two adjacent words within a sentence) and subject islands (created by extracting a wh-phrase out of an embedded subject). The comparison of these violations to control sentences surprisingly showed no indication of a generalized violation response, with almost completely divergent activation patterns. Phrase structure violations seemingly activated regions previously implicated in verbal working memory and structural complexity in sentence processing, whereas the subject islands appeared to activate regions previously implicated in conceptual-semantic processing, broadly defined. We review our findings in the context of previous research on syntactic and semantic violations using event-related potentials. Although our results suggest potentially distinct underlying mechanisms underlying phrase structure and subject island violations, our results are tentative and suggest important methodological considerations for future research in this area.

How well can simple clinical features predict long-term language recovery after left-hemisphere glioma surgery?

Long-term language recovery after left-hemisphere glioma surgery varies substantially across patients. We investigated how well it can be predicted using clinical variables such as the postoperative decline in language processing, tumor grade, resection volume and location, extent of resection, and intraoperative language mapping. Beyond predicting the overall recovery, we examined which domains of language processing are most prone to persistent deficits. Fifty-nine patients with left-hemisphere gliomas completed the Russian Aphasia Test (RAT) before surgery, immediately after surgery, and at follow-up three to seventeen months after surgery. We modeled their average language score (Generalized Aphasia Quotient, GAQ) at follow-up using a cross-validated multiple linear regression and calculated the number of patients showing persistent deficits in each subtest of the RAT. The difference between GAQ scores at follow-up and before surgery was not significant at the group level but varied substantially across patients (mean -1.3%, range -34.2-9.2%). Our best-performing model predicted the follow-up GAQ scores with the mean absolute error of 3.5% (cross-validated R2 = 0.15). A greater decline in language processing immediately after surgery predicted worse recovery, whereas intraoperative language mapping predicted better recovery. Deficits in sentence repetition, verb production, verb and sentence comprehension, and object naming most often persisted at follow-up. The postoperative decline in language processing and intraoperative language mapping explain a substantial amount of variability in long-term language recovery. Verbal working memory and lexical retrieval, particularly that of verbs, are most prone to persistent deficits.

The effects of multitalker babble noise on children's cognitive performance

Classroom noise, particularly irrelevant speech or background babble noise, can have detrimental effects on academic tasks and learning more generally. Researchers have proposed two alternative explanations of the interference of babble noise on non-auditory academic tasks, such as reading or math: i) Babble noise may generate interference on these tasks due to the automatic access of speech sounds (babbling) to phonological short-term memory; or ii) by capturing children's attention, thereby diverting general attentional resources from the task. To test these hypotheses, we asked 3rd to 5th graders to perform two visual attention and two verbal working memory tasks (digit span and reading span) in both quiet and noisy conditions. Multitalker babble noise was administered through headphones at 65dB. The results revealed significant noise effects only in the most complex verbal working memory task (reading span). Interestingly, a significant difference between conditions was also observed in one of the visual attention tasks, where higher scores were, however, achieved in the presence of noise. These preliminary findings will be discussed in light of the current literature.

Is Working Memory Necessary for Both Selection and Calculation in Level 1 Visual Perspective Taking? Evidence from Children and Adults.

Previous research has suggested that there are two modular processes of perspective selection and calculation in level 1 perspective taking. Evidence further showed that verbal working memory is associated with both processes in adults. However, research has not tested whether verbal working memory may be associated with working memory in children. Moreover, since perspective taking is associated with spatial working memory, it is necessary to investigate whether spatial working memory links to both processes. By recruiting 9-year-old children and college students in the single-task paradigm and the dual-task paradigm, we conducted two experiments to answer these questions. Results in experiment 1 suggested that verbal working memory correlated with adults' perspective calculation, but with both processes in children's perspective taking. Results in experiment 2 showed that spatial working memory is associated with adults' perspective calculation and children's perspective selection. These findings suggest that different components of working memory play distinct roles in the processing of perspective taking, which is moderated by age.

The Grenada Learning and Memory Scale: Psychometric features and normative data in Caribbean preschool children.

Neuropsychological assessment of preschool children is essential for early detection of delays and referral for intervention prior to school entry. This is especially pertinent in low- and middle-income countries (LMICs), which are disproportionately impacted by micronutrient deficiencies and teratogenic exposures. The Grenada Learning and Memory Scale (GLAMS) was created for use in limited resource settings and includes a shopping list and face-name association test. Here, we present psychometric and normative data for the GLAMS in a Grenadian preschool sample. Typically developing children between 36 and 72 months of age, primarily English speaking, were recruited from public preschools in Grenada. Trained Early Childhood Assessors administered the GLAMS and NEPSY-II in schools, homes, and clinics. GLAMS score distributions, reliability, and convergent/divergent validity against NEPSY-II were evaluated. The sample consisted of 400 children (190 males, 210 females). GLAMS internal consistency, inter-rater agreement, and test-retest reliability were acceptable. Principal components analysis revealed two latent factors, aligned with expected verbal/visual memory constructs. A female advantage was observed in verbal memory. Moderate age effects were observed on list learning/recall and small age effects on face-name learning/recall. All GLAMS subtests were correlated with NEPSY-II Sentence Repetition, supporting convergent validity with a measure of verbal working memory. The GLAMS is a psychometrically sound measure of learning and memory in Grenadian preschool children. Further adaptation and scale-up to global LMICs are recommended.

Aging Processes of Working Memory in Different Modalities.

Background: Working memory (WM) involves temporarily storing and manipulating information. Research on the impact of aging on WM has shown inconsistent results regarding the decline in visual and verbal WM, with a lack of studies on tactile WM. This study aimed to assess the effects of aging on WM across verbal, visuospatial, and tactile modalities using span tasks of forward (storage) and backward (manipulation) stages. Methods: A total of 130 participants, divided into four age groups of 20-29, 60-69, 70-79, and 80-89, completed the Digit, Visuospatial, and Tactual Spans. Performance was analyzed using a 3 (Task) × 4 (Group) × 2 (Stage) mixed design repeated measures ANOVA. Results: The analysis revealed significant main effects for modality (p < 0.001, ηp2 = 0.15), age (p < 0.001, ηp2 = 0.48), and stage (p < 0.001, ηp2 = 0.30). Digit Span outperformed the other modalities, while Tactual Span showed the worst performance. Additionally, task performance declined with age, and the forward stage was superior to the backward stage. Interaction effects indicated that Digit Span was less affected by aging compared to the Visuospatial and Tactual Spans (p = 0.004, ηp2 = 0.07). Post hoc analyses further revealed that the Digit Span consistently outperformed the other modalities in both stages, with more pronounced differences observed in the forward stage. Conclusions: Verbal WM is more resilient to aging compared to the other modalities while tactile WM declines with age in a manner similar to verbal and visuospatial WM, suggesting a modality-specific impact of aging on WM.