The multi-component model of working memory: Explorations in experimental cognitive psychology

Empirical examination of working memory performance and its neural correlates in relation to delay discounting in two large samples

The neurobiological basis of working memory and delay discounting are theorized to overlap, but few studies have empirically examined these relations in large samples. To address this, we investigated the association of neural activation during an fMRI N-Back working memory task with delay discounting area, as well as in- and out-of-scanner working memory measures. These analyses were conducted in two large task fMRI datasets, the Human Connectome Project and the Adolescent Brain Cognitive Development Study. Although in- and out-of-scanner working memory performance were significantly associated with N-back task brain activation regions, contrary to our hypotheses, there were no significant associations between working memory task activation and delay discounting scores. These findings call into question the extent of the neural overlap in delay discounting and working memory and highlight the need for more investigations directly interrogating overlapping and distinct brain regions across cognitive neuroscience tasks.

Shared characteristics of intervention techniques for oral vocabulary and speech comprehensibility in preschool children with co-occurring features of developmental language disorder and speech sound disorder: a systematic review with narrative synthesis

OBJECTIVES

To descriptively compare and contrast intervention techniques for preschool children with features of developmental language disorder (outcome: oral vocabulary) and speech sound disorder (outcome: speech comprehensibility) and analyse them in relation to effectiveness and theory.

DESIGN

This is a systematic review with narrative synthesis. The process was supported by an expert steering group consisting of relevant professionals and people with lived experience.

DATA SOURCES

Ovid Emcare, MEDLINE Complete, CINAHL, APA PsycINFO, ERIC, and Communication Source from January 2012 were searched. Relevant studies were obtained from an initial published review (up to January 2012).

ELIGIBILITY CRITERIA

Interventions for preschool children (80% aged 2:0-5:11 years) with idiopathic speech or language needs; outcomes relating to either oral vocabulary or speech comprehensibility.

DATA EXTRACTION AND SYNTHESIS

Searches were conducted on 27 January 2023. Two independent researchers screened at abstract and full-text levels. Data regarding intervention content (eg, techniques) and format/delivery (eg, dosage, location) were extracted. Data were synthesised narratively according to the methods of Campbell et al.

RESULTS

24 studies were included: 18 for oral vocabulary and 6 for speech comprehensibility. There were 11 randomised controlled trials, 2 cohort studies and 11 case series. Similarities included a focus on input-related techniques and similar therapy activities. Speech studies were more likely to be professional-led and clinic-led, rather than at home and through a parent. Analysis was restricted by heterogeneity in study design and terminology, as well as gaps within intervention reporting. Information deemed important to the expert steering group was missing.

CONCLUSIONS

Similarities and differences between intervention techniques for oral vocabulary and speech comprehensibility have been identified and synthesised. However, analysis of effectiveness was limited due to issues with study design and heterogeneity within studies. This has implications for the progression of the evidence base within the field.

PROSPERO REGISTRATION NUMBER

CRD42022373931.

Does epilepsy differentially affect different types of memory?

Despite the recognition that epilepsy can substantially disrupt memory, there are few published accounts of whether and how this disruption varies across different types of memory and/or different types of epilepsy. This review explores four main questions: (1) Are working, episodic and semantic memory differentially affected by epilepsy? (2) Do various types of epilepsy, and their treatment, have different, specifiable effects on memory? (3) Are the usual forms of neuropsychological assessments of memory - many or most designed for other conditions - appropriate for patients with epilepsy? (4) How can research on epilepsy contribute to our understanding of the neuroscience of memory? We conclude that widespread and multifactorial problems are seen in working memory in all patient groups, while patients with temporal lobe epilepsy seem particularly prone to episodic memory deficit, and those with frontal lobe epilepsy to executive function deficits that may in turn impair semantic control. Currently, it is difficult to make individual patient predictions about likely memory deficits based on seizure aetiology and type, but it is possible to guide and tailor neuropsychological assessments in an individualised way. We make recommendations for future directions in validating and optimising neuropsychological assessments, and consider how to approach effective shared decision making about the pros and cons of seizure treatment strategies, especially at crucial educational stages such as adolescence.

Visuospatial working memory in behavioural variant frontotemporal dementia: a comparative analysis with Alzheimer's disease using the box task

OBJECTIVE

This study investigated the visuospatial working memory profiles of behavioural variant frontotemporal dementia (bvFTD) and Alzheimer's disease (AD) using a novel computerised test of visuospatial working memory: the Box Task.

METHODS

Twenty-eight bvFTD and 28 AD patients, as well as 32 age-matched control participants were recruited. All participants completed the Box Task and conventional neuropsychological tests of working memory, episodic memory, and visuospatial function.

RESULTS

Both the bvFTD and AD groups exhibited significantly more Box Task between-search errors than the control group across all set sizes. Notably, the AD group demonstrated a significantly higher error rate compared to the bvFTD group. Regression analysis revealed that whilst episodic memory impairment significantly predicted Box Task error performance in AD, this was not the case for bvFTD. Additionally, a noticeable trend was observed for attention in predicting Box Task errors in both bvFTD and AD groups. The Box Task demonstrated high utility in differentiating between bvFTD and AD, with a decision tree correctly classifying 82.1% of bvFTD patients and 75% of AD patients.

CONCLUSIONS

Our findings reveal significant visuospatial working memory impairments in bvFTD, albeit of lesser severity compared to disease-matched AD patients. The Box Task, a novel measure of visuospatial working memory, proved effective in differentiating between bvFTD and AD, outperforming many traditional neuropsychological measures. Overall, our findings highlight the utility of assessing visuospatial memory when differentiating between bvFTD and AD in the clinical setting.

Selective interference of liking and beauty judgements on affective working memory and visual working memory

Aesthetic processing has profound implications for everyday life. Although liking and beauty judgements are outcomes of aesthetic processing and derive from a common hedonic value, there may be some differences in how they engage working memory. This study used maintenance and aesthetic judgement tasks to examine whether liking and beauty judgements make different demands on domain-specific working memory resources. Sixty participants (30 males) were instructed to rate picture for liking or beauty while maintaining the subjective affect or brightness of the presented pictures. Results indicated that liking judgements selectively impaired participants' performance in the affect maintenance task, and beauty judgements selectively impaired their performance in the brightness maintenance task. In addition, maintaining affect and brightness feelings in the mind increased image ratings on beauty but not on liking. Our findings provide evidence that liking judgements draw more on affective working memory resources than beauty judgements, and beauty judgements draw more on visual working memory resources than liking judgements.

Deciphering brain cellular and behavioral mechanisms: Insights from single-cell and spatial RNA sequencing

The brain is a complex computing system composed of a multitude of interacting neurons. The computational outputs of this system determine the behavior and perception of every individual. Each brain cell expresses thousands of genes that dictate the cell's function and physiological properties. Therefore, deciphering the molecular expression of each cell is of great significance for understanding its characteristics and role in brain function. Additionally, the positional information of each cell can provide crucial insights into their involvement in local brain circuits. In this review, we briefly overview the principles of single-cell RNA sequencing and spatial transcriptomics, the potential issues and challenges in their data processing, and their applications in brain research. We further outline several promising directions in neuroscience that could be integrated with single-cell RNA sequencing, including neurodevelopment, the identification of novel brain microstructures, cognition and behavior, neuronal cell positioning, molecules and cells related to advanced brain functions, sleep-wake cycles/circadian rhythms, and computational modeling of brain function. We believe that the deep integration of these directions with single-cell and spatial RNA sequencing can contribute significantly to understanding the roles of individual cells or cell types in these specific functions, thereby making important contributions to addressing critical questions in those fields. This article is categorized under: RNA Evolution and Genomics > Computational Analyses of RNA RNA in Disease and Development > RNA in Development RNA in Disease and Development > RNA in Disease.

Hearing fearful prosody impairs visual working memory maintenance

Interference by distractors has been associated multiple times with diminished visual and auditory working memory (WM) performance. Negative emotional distractors in particular lead to detrimental effects on WM. However, these associations have only been seen when distractors and items to maintain in WM are from the same sensory modality. In this study, we investigate cross-modal interference on WM. We invited 20 participants to complete a visual change-detection task, assessing visual WM (VWM), while hearing emotional (fearful) and neutral auditory distractors. Electrophysiological activity was recorded to measure contralateral delay activity (CDA) and auditory P2 event-related potentials (ERP), indexing WM maintenance and distractor salience respectively. At the behavioral level, fearful prosody didn't decrease significantly working memory accuracy, compared to neutral prosody. Regarding ERPs, fearful distractors evoked a greater P2 amplitude than neutral distractors. Correlations between the two ERP potentials indicated that P2 amplitude difference between the two types of prosody was associated with the difference in CDA amplitude for fearful and neutral trials. This association suggests that cognitive resources required to process fearful prosody detrimentally impact VWM maintenance. That result provides a piece of additional evidence that negative emotional stimuli produce greater interference than neutral stimuli and that the cognitive resources used to process stimuli from different modalities come from a common pool.

Complex PTSD symptom clusters and executive function in UK Armed Forces veterans: a cross-sectional study

BACKGROUND

Less is known about complex posttraumatic stress disorder (CPTSD) than postrraumatic stress disorder (PTSD) in military veterans, yet this population may be at greater risk of the former diagnosis. Executive function impairment has been linked to PTSD treatment outcomes. The current study therefore aimed to explore possible associations between each CPTSD symptom cluster and executive function to understand if similar treatment trajectories might be observed with the disorder.

METHODS

A total of 428 veterans from a national charity responded to a self-report questionnaire which measured CPTSD symptom clusters using the International Trauma Questionnaire, and executive function using the Adult Executive Function Inventory. Single and multiple linear regression models were used to analyse the relationship between CPTSD symptom clusters and executive function, including working memory and inhibition.

RESULTS

Each CPTSD symptom cluster was significantly associated with higher executive function impairment, even after controlling for possible mental health confounding variables. Emotion dysregulation was the CPTSD symptom cluster most strongly associated with executive function impairment.

CONCLUSIONS

This is the first study to explore the relationship between executive function and CPTSD symptom clusters. The study builds on previous findings and suggests that executive function could be relevant to CPTSD treatment trajectories, as is the case with PTSD alone. Future research should further explore such clinical implications.

Orthographic Learning in French-Speaking Deaf and Hard of Hearing Children

PURPOSE

Children are assumed to acquire orthographic representations during autonomous reading by decoding new written words. The present study investigates how deaf and hard of hearing (DHH) children build new orthographic representations compared to typically hearing (TH) children.

METHOD

Twenty-nine DHH children, from 7.8 to 13.5 years old, with moderate-to-profound hearing loss, matched for reading level and chronological age to TH controls, were exposed to 10 pseudowords (novel words) in written stories. Then, they performed a spelling task and an orthographic recognition task on these new words.

RESULTS

In the spelling task, we found no difference in accuracy, but a difference in errors emerged between the two groups: Phonologically plausible errors were less common in DHH children than in TH children. In the recognition task, DHH children were better than TH children at recognizing target pseudowords. Phonological strategies seemed to be used less by DHH than by TH children who very often chose phonological distractors.

CONCLUSIONS

Both groups created sufficiently detailed orthographic representations to complete the tasks, which support the self-teaching hypothesis. DHH children used phonological information in both tasks but could use more orthographic cues than TH children to build up orthographic representations. Using the combination of a spelling task and a recognition task, as well as analyzing the nature of errors, in this study, provides a methodological implication for further understanding of underlying cognitive processes.

Midlife hypertension is a risk factor for some, but not all, domains of cognitive decline in later life: a systematic review and meta-analysis

INTRODUCTION

Management of midlife blood pressure and hypertension status may provide a window of intervention to mitigate cognitive decline with advancing age. The aim of this review was to investigate the relationship between midlife hypertension and cognition in midlife and later life.

METHODS

Online electronic databases were searched from their inception to May 2022. Studies assessing midlife (40-65 years) hypertension and cognition at mid and/or later-life were included. A random effects meta-analysis was deemed appropriate.

RESULTS

One hundred forty-nine studies across 26 countries were included. Qualitative synthesis found negative relationships between midlife hypertension and later life cognition in the domains of memory, executive function, and global cognition. Metanalytical evidence revealed midlife hypertension negatively impacts memory, executive function, and global cognition but had no observed effect on attention at midlife.

DISCUSSION

Hypertension at midlife has a significant negative impact on cognition in mid-life and later life, namely memory, executive function, and global cognition.

What is it like to do a visuo-spatial working memory task: A qualitative phenomenological study of the visual span task

Working memory is typically measured with specifically designed psychological tasks. When evaluating the validity of working memory tasks, we commonly focus on the reliability of the outcome measurements. Only rarely do we focus on how participants experience these tasks. Accounting for lived experience of working memory task may help us better understand variability in working memory performance and conscious experience in general. We replicated recently established protocols for the phenomenological investigation of working memory using the visual span task. We collected subjective reports from eighteen healthy participants (10 women) aged 21 to 35 years. We observed that working memory can be phenomenologically characterized at three different time scales: background feelings, strategies, and tactics. On the level of tactics, we identified transmodality (i.e., how one modality of lived experience can be transformed into another one) as the central phenomenological dynamic at play during working memory task performance.

Sex-specific impulsivity, but not other facets of executive function, predicts fat and sugar intake two-years later amongst adolescents with a healthy weight: Findings from the ABCD study

During adolescence, processes that control food intake (executive functions [EF]) undergo extensive refinement; underlying differences in EF may explain the inability to resist overeating unhealthy foods. Yet, overeating fat and sugar also causes changes to EF and cognition but disentangling these relationships has been difficult, as previous studies included youth with obesity. Here, amongst youth initially of a healthy weight, we evaluate whether 1) sex-specific underlying variation in EF/cognition at 9/10-years-old predict fat/sugar two-years later (Y2) and 2) if these relationships are moderated by body mass index (BMI), using linear mixed effects models (controlled for puberty, caregiver education; random effect: study site). Data were leveraged from Adolescent Brain Cognitive Development Study (n = 2987; 50.4% male; 15.4% Latino/a/x; 100% healthy weight at baseline; 12.4% overweight/obese by Y2, data release 4.0). EF and cognition (e.g., inhibition, cognition, motor, memory, impulsivity) were assessed with the NIH toolbox, Rey Auditory Verbal Learning Task, Little Man Task, the BIS/BAS, and UPPS-P. A saturated fat/added sugar (kcals) composite score was extracted from the validated Kids Food Block Screener. For males, greater baseline impulsivity (e.g., Positive Urgency, Lack of Planning and Perseverance) and reward (e.g., Fun seeking, Drive) was related to greater Y2 intake. For both sexes, greater baseline Negative Urgency and higher BMI was related to greater Y2 intake. No other relationships were observed. Our findings highlight a phenotype that may be more at risk for weight gain due to overconsumption of fat/sugar. Thus, prevention efforts may wish to focus on impulsive tendencies for these foods.

The 10-Word Auditory Verbal Learning Test and Vocabulary Performance in 4- and 5-Year-Old Children

BACKGROUND

Understanding the different factors that determine vocabulary development in young children is essential for the diagnosis and rehabilitation of language disorders in children. Language development is closely related to other cognitive processes such as auditory verbal learning and memory. This research focuses on the development of a novel auditory verbal learning test (AVLT) for 4- and 5-year-old children within the Dutch population. This new test is an adaptation of the common AVLT for both older children and adults, usually including a list of 15 words. Considering the lower attention span and limited executive functioning in young children, the word list of this new instrument is reduced to 10 words. Besides, a second recognition form has been developed to improve the ability to distinguish between possible underlying learning and memory deficits.

METHOD

Ninety-five preschool children (ages 4;0-5;12 [years;months]) were tested with this new AVLT 10-word test for kids (10WT-K), yielding different measures of verbal auditory memory. Forty-eight of 95 children received a recognition task with semantically unrelated items, and 47 of 95 received a recognition task with semantically related items. Three additional language skills were assessed to establish test validation: receptive and expressive vocabulary performance and nonword repetition. Outcome of the 10WT-K was related to scores on the language measures.

RESULTS

Positive correlations were found between the total score of the 10WT-K and all three aforementioned language skills. We found no correlations between frequency of error types (intrusions and repetitions) and language measures. Furthermore, children who were administered the recognition list with semantically related items showed fewer correct answers and more false-positive and false-negative responses than children who received a recognition list with semantically unrelated items.

CONCLUSIONS

The 10WT-K for young children can be used to (a) measure different aspects of auditory verbal learning and memory, (b) clarify the nature of possible verbal learning difficulties, and (c) identify a possible nature of language disorders. The word recognition task tested with semantically related items provides a more accurate measurement of individual differences, namely, in distinguishing retrieval and storage abilities. The significant relation found between auditory verbal short-term memory capacity and vocabulary performance in preschool children is a first step toward establishing test validity.

Cognitive dysfunction in post-COVID-19 condition: Mechanisms, management, and rehabilitation

The long-term effects of COVID-19 on cognitive function have become an area of increasing concern. This paper provides an overview of characteristics, risk factors, possible mechanisms, and management strategies for cognitive dysfunction in post-COVID-19 condition (PCC). Prolonged cognitive dysfunction is one of the most common impairments in PCC, affecting between 17% and 28% of the individuals more than 12 weeks after the infection and persisting in some cases for several years. Cognitive dysfunctions can be manifested as a wide range of symptoms including memory impairment, attention deficit, executive dysfunction, and reduced processing speed. Risk factors for developing PCC, with or without cognitive impairments, include advanced age, preexisting medical conditions, and the severity of acute illness. The underlying mechanisms remain unclear, but proposed contributors include neuroinflammation, hypoxia, vascular damage, and latent virus reactivation not excluding the possibility of direct viral invasion of the central nervous system, illustrating complex viral pathology. As the individual variation of the cognitive impairments is large, a neuropsychological examination and a person-centered multidimensional approach are required. According to the World Health Organization, limited evidence on COVID-19-related cognitive impairments necessitates implementing rehabilitation interventions from established practices of similar conditions. Psychoeducation and compensatory skills training are recommended. Assistive products and environmental modifications adapted to individual needs might be helpful. In specific attention- and working memory dysfunctions, cognitive training-carefully monitored for intensity-might be effective for people who do not suffer from post-exertional malaise. Further research is crucial for evidence-based interventions specific to COVID-19-related cognitive impairments.

Variation in executive function relates to BMI increases in youth who were initially of a healthy weight in the ABCD Study

OBJECTIVE

The study aim was to determine whether (A) differences in executive function (EF) and cognition precede weight gain or (B) weight gain causes changes to EF and cognition.

METHODS

Data were gathered from the Adolescent Brain Cognitive Development (ABCD) Study (release 4.0; ages 9-12 years old [N = 2794]; 100% had healthy weight at baseline [i.e., 9/10 years old], 12.4% had unhealthy weight by ages 11/12 years). EF and cognition were assessed across several domains (e.g., impulsivity, inhibitory control, processing speed, memory); BMI was calculated from height and weight. Nested random-effects mixed models examined (A) BMI ~ EF × Time (i.e., variation in EF/cognition precedes weight gain) and (B) EF ~ BMI × Time (weight gain causes changes to EF/cognition) and controlled for sex, puberty, and caregiver education; random effects were site and subject.

RESULTS

Variation in impulsivity, memory, learning, and processing speed was associated with greater increases in BMI trajectories from 9 to 12 years old. Weight gain was associated with a decrease in inhibitory control, but no other associations were observed.

CONCLUSIONS

Underlying variation in EF and cognition may be important for weight gain, but 2 years of weight gain may not be enough to have clinical implications for EF and cognition beyond inhibitory control. These findings suggest that more attention should be paid to the inclusion of EF programs in obesity prevention efforts.

A data-driven network decomposition of the temporal, spatial, and spectral dynamics underpinning visual-verbal working memory processes

The brain dynamics underlying working memory (WM) unroll via transient frequency-specific large-scale brain networks. This multidimensionality (time, space, and frequency) challenges traditional analyses. Through an unsupervised technique, the time delay embedded-hidden Markov model (TDE-HMM), we pursue a functional network analysis of magnetoencephalographic data from 38 healthy subjects acquired during an n-back task. Here we show that this model inferred task-specific networks with unique temporal (activation), spectral (phase-coupling connections), and spatial (power spectral density distribution) profiles. A theta frontoparietal network exerts attentional control and encodes the stimulus, an alpha temporo-occipital network rehearses the verbal information, and a broad-band frontoparietal network with a P300-like temporal profile leads the retrieval process and motor response. Therefore, this work provides a unified and integrated description of the multidimensional working memory dynamics that can be interpreted within the neuropsychological multi-component model of WM, improving the overall neurophysiological and neuropsychological comprehension of WM functioning.

Inhibition, Attentional Control and Binding Abilities in Relation to Dissociative Symptoms Among PTSD Patients

INTRODUCTION

The relationship between dissociation and cognitive abilities remains controversial. Empirical studies have reported positive, negative and non-existent associations between dissociation and cognition. These inconsistent results may be due to the fact that the studies focused mainly on trait dissociation, while dissociation is not stable but transient. After validating the French version of the Clinician Administered Dissociative States Scale (CADSS), the aim of the present study was to evaluate the relationship between state dissociation and cognitive abilities.

METHOD

We recruited 83 patients suffering from post-traumatic stress disorder (PTSD) and assessed them twice. At T1, they performed a neutral Stroop task and a neutral binding task. At T2 (one to three weeks later), after a script-driven dissociative induction, they performed an emotional Stroop task and an emotional binding task. Between the two sessions, they completed questionnaires at home evaluating PTSD severity, trait dissociation and cognitive difficulties. State dissociation was assessed at T1 and T2 using the Clinician-Administered Dissociative States Scale (CADSS).

RESULTS

We found good psychometric properties of the French version of the CADSS. After inducing dissociation, significantly lower attentional performance was found among patients with than without dissociative reactions. We found a significant positive correlation between state dissociation and increased attention and memory difficulties after induction.

CONCLUSION

The French version of the CADSS is a reliable and valid tool to assess state dissociation, which is correlated with attentional difficulties. Attentional training is recommended to help patients control dissociative symptoms.

Differences in auditory verbal working memory between adults who do and do not stutter on an N-back task

PURPOSE

The purpose of this study was to investigate auditory verbal working memory in adults who do (AWS) and do not (AWNS) stutter using a highly demanding linguistic N-back task.

METHODS

Fifteen AWS and 15 AWNS matched in age, gender and educational level were asked to hear series of words and respond by pressing a "yes" button if the word they just heard was the same as the word one, two, or three trials back. Words were either phonologically similar (i.e., Phonological Linguistic Condition) or phonologically dissimilar (i.e., Neutral Linguistic Condition). Accuracy and false alarms rates as well as reaction time on correct target trials, missed target trials and false alarms were collected and analyzed.

RESULTS

Differences were not found between AWS and AWNS in accuracy. Both groups were more accurate and significantly faster in 1- followed by 2- followed by 3-back trials. However, AWS were significantly slower than AWNS in the 2-back level, regardless of linguistic condition. Furthermore, AWS demonstrated more false alarms compared to AWNS.

CONCLUSION

Results revealed differences in auditory verbal working memory and interference control between AWS and AWNS when processing highly linguistically demanding stimuli.

A Slip Between the Brain and the Lip: Working Memory and Cognitive-Communication Disorders

The relationship between working memory and speech has been a topic of intense research interest and investigation for many years. Memory studies have found that the active processing of working memory is required for language comprehension and speech production. Though there are studies that discuss the capacity of working memory, the processing of verbal stimuli into verbal memory remains unclear. Therefore, it is essential to understand the functioning of the working memory and how it processes verbal information. As working memory is intricately linked with communication, any deficits in working memory could cause communication disorders. Also, the disruption in the storage and retrieval of verbal memory could cause a disturbance in the speech pattern. To this point, this review elaborates on the active processing of working memory and its role in communication. Further, by studying the deficits in working memory that could cause cognitive-communication disorders such as apraxia of speech, dementia, and dysarthria, this article highlights the importance of verbal memory in speech.

Cognitive neuroscience perspective on memory: overview and summary

This paper explores memory from a cognitive neuroscience perspective and examines associated neural mechanisms. It examines the different types of memory: working, declarative, and non-declarative, and the brain regions involved in each type. The paper highlights the role of different brain regions, such as the prefrontal cortex in working memory and the hippocampus in declarative memory. The paper also examines the mechanisms that underlie the formation and consolidation of memory, including the importance of sleep in the consolidation of memory and the role of the hippocampus in linking new memories to existing cognitive schemata. The paper highlights two types of memory consolidation processes: cellular consolidation and system consolidation. Cellular consolidation is the process of stabilizing information by strengthening synaptic connections. System consolidation models suggest that memories are initially stored in the hippocampus and are gradually consolidated into the neocortex over time. The consolidation process involves a hippocampal-neocortical binding process incorporating newly acquired information into existing cognitive schemata. The paper highlights the role of the medial temporal lobe and its involvement in autobiographical memory. Further, the paper discusses the relationship between episodic and semantic memory and the role of the hippocampus. Finally, the paper underscores the need for further research into the neurobiological mechanisms underlying non-declarative memory, particularly conditioning. Overall, the paper provides a comprehensive overview from a cognitive neuroscience perspective of the different processes involved in memory consolidation of different types of memory.

Evolution of Cognitive Impairments in Treatment-Resistant Depression: Results from the Longitudinal French Centers of Expertise for Treatment-Resistant Depression (FACE-DR) Cohort

Previous studies set out profound cognitive impairments in subjects with treatment-resistant depression (TRD). However, little is known about the course of such alterations depending on levels of improvement in those patients followed longitudinally. The main objective of this study was to describe the course of cognitive impairments in responder versus non-responder TRD patients at one-year follow-up. The second aim was to evaluate the predictive aspect of cognitive impairments to treatment resistance in patients suffering from TRD. We included 131 patients from a longitudinal cohort (FACE-DR) of the French Network of Expert TRD Centers. They undertook comprehensive sociodemographic, clinical, global functioning, and neuropsychological testing (TMT, Baddeley task, verbal fluencies, WAIS-4 subtests, D2 and RLRI-16) at baseline (V0) and one-year follow-up (V1). Most patients (n = 83; 63.36%) did not respond (47 women, 49.47 ± 12.64 years old), while one-third of patients responded (n = 48, 30 women, 54.06 ± 12.03 years old). We compared the cognitive performances of participants to average theoretical performances in the general population. In addition, we compared the cognitive performances of patients between V1 and V0 and responder versus non-responder patients at V1. We observed cognitive impairments during the episode and after a therapeutic response. Overall, each of them tended to show an increase in their cognitive scores. Improvement was more prominent in responders at V1 compared to their non-responder counterparts. They experienced a more marked improvement in code, digit span, arithmetic, similarities, and D2 tasks. Patients suffering from TRD have significant cognitive impairments that persist but alleviate after therapeutic response. Cognitive remediation should be proposed after therapeutic response to improve efficiency and increase the daily functioning.

Would frontal midline theta indicate cognitive changes induced by non-invasive brain stimulation? A mini review

To the best of our knowledge, neurophysiological markers indicating changes induced by non-invasive brain stimulation (NIBS) on cognitive performance, especially one of the most investigated under these procedures, working memory (WM), are little known. Here, we will briefly introduce frontal midline theta (FM-theta) oscillation (4-8 Hz) as a possible indicator for NIBS effects on WM processing. Electrophysiological recordings of FM-theta oscillation seem to originate in the medial frontal cortex and the anterior cingulate cortex, but they may be driven more subcortically. FM-theta has been acknowledged to occur during memory and emotion processing, and it has been related to WM and sustained attention. It mainly occurs in the frontal region during a delay period, in which specific information previously shown is no longer perceived and must be manipulated to allow a later (delayed) response and observed in posterior regions during information maintenance. Most NIBS studies investigating effects on cognitive performance have used n-back tasks that mix manipulation and maintenance processes. Thus, if considering FM-theta as a potential neurophysiological indicator for NIBS effects on different WM components, adequate cognitive tasks should be considered to better address the complexity of WM processing. Future research should also evaluate the potential use of FM-theta as an index of the therapeutic effects of NIBS intervention on neuropsychiatric disorders, especially those involving the ventral medial prefrontal cortex and cognitive dysfunctions.

Genuine beta bursts in human working memory: controlling for the influence of lower-frequency rhythms

Human working memory is associated with significant modulations in oscillatory brain activity. However, the functional role of brain rhythms at different frequencies is still debated. Modulations in the beta frequency range (15-40 Hz) are especially difficult to interpret because they could be artifactually produced by (more prominent) oscillations in lower frequencies that show non-sinusoidal properties. In this study, we investigate beta oscillations during working memory while controlling for the possible influence of lower frequency rhythms. We collected electroencephalography (EEG) data in 31 participants who performed a spatial working-memory task with two levels of cognitive load. In order to rule out the possibility that observed beta activity was affected by non-sinusoidalities of lower frequency rhythms, we developed an algorithm that detects transient beta oscillations that do not coincide with more prominent lower frequency rhythms in time and space. Using this algorithm, we show that the amplitude and duration of beta bursts decrease with memory load and during memory manipulation, while their peak frequency and rate increase. In addition, interindividual differences in performance were significantly associated with beta burst rates. Together, our results show that beta rhythms are functionally modulated during working memory and that these changes cannot be attributed to lower frequency rhythms with non-sinusoidal properties.

Visuo-Spatial Working Memory and Mathematical Skills in Children: A Network Analysis Study

Visuo-spatial working memory is one of the main domain-general cognitive mechanisms underlying mathematical abilities and their development in children. However, if visuo-spatial working memory involves different processes and components, then the term 'mathematics' refers to a broad concept that includes multiple domains and skills. The aim of this present study was to investigate the relationship between different visuo-spatial working memory components and several mathematical abilities in a sample of third- to fifth-grade Italian children. To assess the relationships between different visuo-spatial working memory components and different mathematical abilities, we relied on Network Analysis (NA). Results indicate that some but not all visuo-spatial working memory components are associated with some mathematical abilities.

Episodic Events as Spatiotemporal Memory: The Sequence of Information in the Episodic Buffer of Working Memory for Language Comprehension

Memory and language are the two higher-order cognitive abilities intertwined for communication and other cognitive skills. Memory is the storage capacity of all the information we perceive. Where the sensory memory perceives the stimuli, the working memory actively stores the information and passes it to the long-term memory. However, there is a question that how is the continuous perception of stimuli transformed into meaningful information and organized for proper execution and retrieval from the memory? This paper focuses on the episodic memory that perceives information that is spatial and temporal based on our everyday experiences. Though the spatiotemporal information we receive is continuous; the episodic memory arranges the information as to episodes in the working memory before the information is stored for a longer period. The episodic buffer is one of the components of the working memory model which holds the episodic memory that is organized concerning time. To this point, the paper tries to understand the working of the episodic buffer in maintaining the episodic memory and also about the process of episodic events into meaningful units. Further, the paper also concentrates on the hippocampus which is considered to be the location of the episodic buffer.

Non-driving related tasks' effects on takeover and manual driving behavior in a real driving setting: A differentiation approach based on task switching and modality shifting

Many studies on effects of non-driving related tasks in the context of SAE Level3 automated driving have been conducted in driving simulator settings applying standardized tasks. Thereby internal validity is favored over external validity. To assess the influence of engagement in three natural non-driving related tasks on takeover behavior in the context of SAE Level3 automated driving, we conducted an experiment on a test track with a sample of naïve participants from the general public. We used a Wizard-of-Oz vehicle to simulate a SAE Level 3 traffic jam function in a real driving setting. To measure effects of compatibility between non-driving related tasks and driving task on subsequent takeover behavior and following manual driving behavior, participants played Tetris, watched a documentary film and read a text and typed a summary of it. After approx. 15 min, each non-driving related task was interrupted by a request to intervene. In the manual driving phase after the third takeover, participants encountered a balloon car positioned on their lane which they had to evade. Results show longer takeover times in the film and text condition compared to the Tetris condition. Implications on theory and practice are discussed.

Consciousness as a Memory System

We suggest that there is confusion between why consciousness developed and what additional functions, through continued evolution, it has co-opted. Consider episodic memory. If we believe that episodic memory evolved solely to accurately represent past events, it seems like a terrible system-prone to forgetting and false memories. However, if we believe that episodic memory developed to flexibly and creatively combine and rearrange memories of prior events in order to plan for the future, then it is quite a good system. We argue that consciousness originally developed as part of the episodic memory system-quite likely the part needed to accomplish that flexible recombining of information. We posit further that consciousness was subsequently co-opted to produce other functions that are not directly relevant to memory per se, such as problem-solving, abstract thinking, and language. We suggest that this theory is compatible with many phenomena, such as the slow speed and the after-the-fact order of consciousness, that cannot be explained well by other theories. We believe that our theory may have profound implications for understanding intentional action and consciousness in general. Moreover, we suggest that episodic memory and its associated memory systems of sensory, working, and semantic memory as a whole ought to be considered together as the conscious memory system in that they, together, give rise to the phenomenon of consciousness. Lastly, we suggest that the cerebral cortex is the part of the brain that makes consciousness possible, and that every cortical region contributes to this conscious memory system.

Cognitive Resources in Working Memory: Domain-Specific or General?

An experiment in the dual-task paradigm was carried out to explore the nature of domain-specific and domain-general resource distribution in working memory. The subjects (N = 32) performed symmetry span and letter reading span tasks under visuospatial (tapping) and verbal (articulatory suppression) cognitive load. The effects of task type and cognitive load modality were analyzed. The results are described within the concentric model framework: significant distinctions in relative accuracy under visuospatial and verbal cognitive load in visuospatial and verbal tasks were observed when N elements in the set exceeded the region of direct access capacity, while no such effect was observed for 2-3 element sets. This is attributed to domain-general resources in the region of direct access, and domain-specific resources in the activated long-term memory. We also found evidence for the asymmetric distribution of visuospatial and verbal working memory resources in that the verbal component is more susceptible to cognitive load.

The negative impact of COVID-19 on working memory revealed using a rapid online quiz

Although coronavirus disease 2019 (COVID-19) affects the respiratory system, it can also have neurological consequences leading to cognitive deficits such as memory problems. The aim of our study was to assess the impact of COVID-19 on working memory function. We developed and implemented an online anonymous survey with a working memory quiz incorporating aspects of gamification to engage participants. 5428 participants successfully completed the survey and memory quiz between 8th December 2020 and 5th July 2021 (68.6% non-COVID-19 and 31.4% COVID-19). Most participants (93.3%) completed the survey and memory quiz relatively rapidly (mean time of 8.84 minutes). Categorical regression was used to assess the contribution of COVID status, age, time post-COVID (number of months elapsed since having had COVID), symptoms, ongoing symptoms and gender, followed by non-parametric statistics. A principal component analysis explored the relationship between subjective ratings and objective memory scores. The objective memory scores were significantly correlated with participants’ own assessment of their cognitive function. The factors significantly affecting memory scores were COVID status, age, time post-COVID and ongoing symptoms. Our main finding was a significant reduction in memory scores in all COVID groups (self-reported, positive-tested and hospitalized) compared to the non-COVID group. Memory scores for all COVID groups combined were significantly reduced compared to the non-COVID group in every age category 25 years and over, but not for the youngest age category (18–24 years old). We found that memory scores gradually increased over a period of 17 months post-COVID-19. However, those with ongoing COVID-19 symptoms continued to show a reduction in memory scores. Our findings demonstrate that COVID-19 negatively impacts working memory function, but only in adults aged 25 years and over. Moreover, our results suggest that working memory deficits with COVID-19 can recover over time, although impairments may persist in those with ongoing symptoms.

Visual working memory recruits two functionally distinct alpha rhythms in posterior cortex

Oscillatory activity in the human brain is dominated by posterior alpha oscillations (8-14 Hz), which have been shown to be functionally relevant in a wide variety of cognitive tasks. Although posterior alpha oscillations are commonly considered a single oscillator anchored at an individual alpha frequency (IAF; ∼10 Hz), previous work suggests that IAF reflects a spatial mixture of different brain rhythms. In this study, we assess whether Independent Component Analysis (ICA) can disentangle functionally distinct posterior alpha rhythms in the context of visual short-term memory retention. Magnetoencephalography (MEG) was recorded in 33 subjects while performing a visual working memory task. Group analysis at sensor level suggested the existence of a single posterior alpha oscillator that increases in power and decreases in frequency during memory retention. Conversely, single-subject analysis of independent components revealed the existence of two dissociable alpha rhythms: one that increases in power during memory retention (Alpha1) and another one that decreases in power (Alpha2). Alpha1 and Alpha2 rhythms were differentially modulated by the presence of visual distractors (Alpha1 increased in power while Alpha2 decreased) and had an opposite relationship with accuracy (positive for Alpha1 and negative for Alpha2). In addition, Alpha1 rhythms showed a lower peak frequency, a narrower peak width, a greater relative peak amplitude and a more central source than Alpha2 rhythms. Together, our results demonstrate that modulations in posterior alpha oscillations during short-term memory retention reflect the dynamics of at least two distinct brain rhythms with different functions and spatiospectral characteristics.Significance statementAlpha oscillations are the most prominent feature of the human brain's electrical activity, and consist of rhythmic neuronal activity in posterior parts of the cortex. Alpha is usually considered a single brain rhythm that changes in power and frequency to support cognitive operations. We here show that posterior alpha entails at least two dissociable rhythms with distinct functions and characteristics. These findings could solve previous inconsistencies in the literature regarding the direction of task-related alpha power/frequency modulations and their relation to cognitive performance. In addition, the existence of two distinct posterior alpha rhythms could have important consequences for the design of neurostimulation protocols aimed at modulating alpha oscillations and subsequently cognition.

Structural Equation Modeling of Common Cognitive Abilities in Preschool-Aged Children Using WPPSI-IV and BRIEF-P

Various studies have addressed the relationship between intelligence and executive functions (EF). There is widespread agreement that EF in preschool children is a unitary construct in which the subordinate factors of Updating, Inhibition, and Shifting are still undifferentiated and correlate moderately with a general factor of intelligence (g). The aim of this study is to investigate the common structural relationship between these two constructs using confirmatory factor analysis. Furthermore, we intend to close the gap of more daily life-associated executive functions and replicate findings in preschool-aged children. Data from a sample of N = 124 average developed children without severe impairments (aged 4 years 0 months–6 years 11 months) were analyzed using the data pool of the standardization and validation studies on the German Wechsler Preschool and Primary Scale of Intelligence—Fourth Edition. Additionally, Executive functions were assessed using a standardized parent-completed questionnaire (BRIEF-P) on their children’s everyday behavior. A second-order factor solution revealed that a model with a loading of the common factor of general intelligence (g-factor) onto the EF factor fits the data best. To specify possible method effects due to different sources of measurements, a latent method factor was generated. The results indicate a heterogeneous method effect and a decreasing factor loading from g on to EF while controlling for the method factor.

What Individuals Experience During Visuo-Spatial Working Memory Task Performance: An Exploratory Phenomenological Study

In experimental cognitive psychology, objects of inquiry are typically operationalized with psychological tasks. When interpreting results from such tasks, we focus primarily on behavioral measures such as reaction times and accuracy rather than experiences - i.e., phenomenology - associated with the task, and posit that the tasks elicit the desired cognitive phenomenon. Evaluating whether the tasks indeed elicit the desired phenomenon can be facilitated by understanding the experience during task performance. In this paper we explore the breadth of experiences that are elicited by and accompany task performance using in-depth phenomenological and qualitative methodology to gather subjective reports during the performance of a visuo-spatial change detection task. Thirty-one participants (18 females) were asked to remember either colors, orientations or positions of the presented stimuli and recall them after a short delay. Qualitative reports revealed rich experiential landscapes associated with the task-performance, suggesting a distinction between two broad classes of experience: phenomena at the front of consciousness and background feelings. The former includes cognitive strategies and aspects of metacognition, whereas the latter include more difficult-to-detect aspects of experience that comprise the overall sense of experience (e.g., bodily feelings, emotional atmosphere, mood). We focus primarily on the background feelings, since strategies of task-performance to a large extent map onto previously identified cognitive processes and discuss the methodological implications of our findings.

Neural Evidence for Different Types of Position Coding Strategies in Spatial Working Memory

Sustained neural activity during the delay phase of spatial working memory tasks is compelling evidence for the neural correlate of active storage and maintenance of spatial information, however, it does not provide insight into specific mechanisms of spatial coding. This activity may reflect a range of processes, such as maintenance of a stimulus position or a prepared motor response plan. The aim of our study was to examine neural evidence for the use of different coding strategies, depending on the characteristics and demands of a spatial working memory task. Thirty-one (20 women, 23 ± 5 years) and 44 (23 women, 21 ± 2 years) participants performed a spatial working memory task while we measured their brain activity using fMRI in two separate experiments. Participants were asked to remember the position of a briefly presented target stimulus and, after a delay period, to use a joystick to indicate either the position of the remembered target or an indicated non-matching location. The task was designed so that the predictability of the response could be manipulated independently of task difficulty and memory retrieval process. We were particularly interested in contrasting conditions in which participants (i) could use prospective coding of the motor response or (ii) had to rely on retrospective sensory information. Prospective motor coding was associated with activity in somatomotor, premotor, and motor cortices and increased integration of brain activity with and within the somatomotor network. In contrast, retrospective sensory coding was associated with increased activity in parietal regions and increased functional connectivity with and within secondary visual and dorsal attentional networks. The observed differences in activation levels, dynamics of differences over trial duration, and integration of information within and between brain networks provide compelling evidence for the use of complementary spatial working memory strategies optimized to meet task demands.

Working Memory and Transcranial-Alternating Current Stimulation-State of the Art: Findings, Missing, and Challenges

Working memory (WM) is a cognitive process that involves maintaining and manipulating information for a short period of time. WM is central to many cognitive processes and declines rapidly with age. Deficits in WM are seen in older adults and in patients with dementia, schizophrenia, major depression, mild cognitive impairment, Alzheimer's disease, etc. The frontal, parietal, and occipital cortices are significantly involved in WM processing and all brain oscillations are implicated in tackling WM tasks, particularly theta and gamma bands. The theta/gamma neural code hypothesis assumes that retained memory items are recorded via theta-nested gamma cycles. Neuronal oscillations can be manipulated by sensory, invasive- and non-invasive brain stimulations. Transcranial alternating-current stimulation (tACS) and repetitive transcranial magnetic stimulation (rTMS) are frequency-tuned non-invasive brain stimulation (NIBS) techniques that have been used to entrain endogenous oscillations in a frequency-specific manner. Compared to rTMS, tACS demonstrates superior cost, tolerability, portability, and safety profile, making it an attractive potential tool for improving cognitive performance. Although cognitive research with tACS is still in its infancy compared to rTMS, a number of studies have shown a promising WM enhancement effect, especially in the elderly and patients with cognitive deficits. This review focuses on the various methods and outcomes of tACS on WM in healthy and unhealthy human adults and highlights the established findings, unknowns, challenges, and perspectives important for translating laboratory tACS into realistic clinical settings. This will allow researchers to identify gaps in the literature and develop frequency-tuned tACS protocols with promising safety and efficacy outcomes. Therefore, research efforts in this direction should help to consider frequency-tuned tACS as a non-pharmacological tool of cognitive rehabilitation in physiological aging and patients with cognitive deficits.

A multi-component, adaptive Working Memory Assessment Battery (WoMAB): validation and norms in an Italian population sample

BACKGROUND

Working memory (WM) abilities are frequently impaired in neurological disorders affecting fronto-parietal cortical/sub-cortical structures. WM deficits negatively influence interventional outcomes and everyday functioning. This study thus aimed at the following: (a) developing and standardizing an ecologically valid task for WM assessment ( Ice Cream Test, ICT); (b) validating and norming a novel WM test (Digit Ordering Test, DOT), as well as providing updated norms for digit span (DS) tasks, in an Italian population sample; (c) introducing a novel scoring procedure for measuring WM.

METHODS

One-hundred and sixty-eight Italian healthy participants-73 male, 95 females; age: 48.4 ± 19.1 (18-86); education: 12.1 ± 4.8 (4-21)-underwent a thorough WM assessment-DOT, ICT, and both forward and backward DS tasks (FDS, BDS). The ICT requires participants to act as waiters who have to keep track of customers' orders. For each task, WM and total (T) outcomes were computed, i.e., the number of elements in the longest sequence and that of recalled sequences, respectively. Norms were derived via the equivalent score (ES) method.

RESULTS

DS ratios (DSRs) were computed for both WM/S and T outcomes on raw DS measures (BDS divided by FDS). Age and education significantly predicted all WM tasks; sex affected FDS and DSR-T scores (males > females). WM measures were highly internally related.

DISCUSSION

The present work provides Italian practitioners with a normatively updated, multi-component, adaptive battery for WM assessment (WoMAB) as well as with novel outcomes which capture different WM facets-WM capacity and attentive monitoring abilities.

The neural correlates of interference control dysfunction of working memory in major depressive disorder: An event-related potential study

Interference control function is a key function in a series of specific functions of working memory (WM), which is usually impaired in patients with major depressive disorder (MDD). Event-related potentials (ERPs) have advantages in exploring the neural processing of interference control and WM impairment, and therefore, it is helpful to further understand the neural mechanism of MDD. In the present study, 44 patients with MDD and 44 age- and sex-matched healthy controls (HCs) were recruited. All participants completed a 4-gradient difficulty Brown-Peterson task (BPT), whose difficulty was manipulated by changing the demand of interspersed distraction tasks. High-density EEG was simultaneously recorded. The hit rate and reaction time (RT) toward the target stimulus as well as the underlying ERP features were analyzed. The results showed that, when compared with HCs, MDD patients had significantly lower hit rates and longer RTs among all four difficulties of BPT. For ERP components, no significant between-group difference was found in either N100 or P200 average amplitudes; however, the centroparietal late positive potential (LPP) amplitude of both MDD group and HC group decreased with the increase of BPT difficulty, despite the pattern of the HC group was relative moderate. For both groups, the LPP amplitude was significantly smaller in high-order difficult BPT tasks than in low-order difficult tasks. Moreover, LPP amplitude in high-order difficult tasks was much smaller in MDD group than that of HC group. Our findings suggest that failure to control interference well may play a critical role in the impairment of WM in patients with MDD, and provided new evidence that the neural correlates of interference control dysfunction of WM in MDD.

Sleep quality and memory function in healthy ageing

OBJECTIVE

To study the relationship between sleep quality and memory in healthy ageing.

METHODS

The study included 99 people older than 50 years (69 women and 30 men; mean age, 68.74±7.18 years) with no associated diseases. Patients completed digital versions of the Word Learning and Visual Paired Associates tests and the Pittsburgh Sleep Quality Index questionnaire to assess the quality of sleep.

RESULTS

Pittsburgh Sleep Quality Index score was negatively correlated with Visual Paired Associates and Word Learning test performance. Performance in these 2 memory tests decreased in line with sleep quality. In addition, performance in Visual Paired Associates test was negatively correlated with subjective sleep quality, duration, and sleep disturbances. Performance on the Word Learning test was negatively correlated with subjective sleep quality and efficiency. Participants' sex showed a weak effect on Visual Paired Associates performance and sleep latency.

CONCLUSIONS

Medical professionals working with elderly patients should take into consideration the effect of poor sleep quality on memory. Cognitive impairment in these patients may be a manifestation of a neuroendocrine imbalance due to a disrupted circadian rhythm. More research is needed to prove this hypothesis.

Changes in audio-spatial working memory abilities during childhood: The role of spatial and phonological development

Working memory is a cognitive system devoted to storage and retrieval processing of information. Numerous studies on the development of working memory have investigated the processing of visuo-spatial and verbal non-spatialized information; however, little is known regarding the refinement of acoustic spatial and memory abilities across development. Here, we hypothesize that audio-spatial memory skills improve over development, due to strengthening spatial and cognitive skills such as semantic elaboration. We asked children aged 6 to 11 years old (n = 55) to pair spatialized animal calls with the corresponding animal spoken name. Spatialized sounds were emitted from an audio-haptic device, haptically explored by children with the dominant hand's index finger. Children younger than 8 anchored their exploration strategy on previously discovered sounds instead of holding this information in working memory and performed worse than older peers when asked to pair the spoken word with the corresponding animal call. In line with our hypothesis, these findings demonstrate that age-related improvements in spatial exploration and verbal coding memorization strategies affect how children learn and memorize items belonging to a complex acoustic spatial layout. Similar to vision, audio-spatial memory abilities strongly depend on cognitive development in early years of life.

A Biological Inspired Cognitive Framework for Memory-Based Multi-Sensory Joint Attention in Human-Robot Interactive Tasks

One of the fundamental prerequisites for effective collaborations between interactive partners is the mutual sharing of the attentional focus on the same perceptual events. This is referred to as joint attention. In psychological, cognitive, and social sciences, its defining elements have been widely pinpointed. Also the field of human-robot interaction has extensively exploited joint attention which has been identified as a fundamental prerequisite for proficient human-robot collaborations. However, joint attention between robots and human partners is often encoded in prefixed robot behaviours that do not fully address the dynamics of interactive scenarios. We provide autonomous attentional behaviour for robotics based on a multi-sensory perception that robustly relocates the focus of attention on the same targets the human partner attends. Further, we investigated how such joint attention between a human and a robot partner improved with a new biologically-inspired memory-based attention component. We assessed the model with the humanoid robot iCub involved in performing a joint task with a human partner in a real-world unstructured scenario. The model showed a robust performance on capturing the stimulation, making a localisation decision in the right time frame, and then executing the right action. We then compared the attention performance of the robot against the human performance when stimulated from the same source across different modalities (audio-visual and audio only). The comparison showed that the model is behaving with temporal dynamics compatible with those of humans. This provides an effective solution for memory-based joint attention in real-world unstructured environments. Further, we analyzed the localisation performances (reaction time and accuracy), the results showed that the robot performed better in an audio-visual condition than an audio only condition. The performance of the robot in the audio-visual condition was relatively comparable with the behaviour of the human participants whereas it was less efficient in audio-only localisation. After a detailed analysis of the internal components of the architecture, we conclude that the differences in performance are due to egonoise which significantly affects the audio-only localisation performance.

Working memory in adults who stutter using a visual N-back task

PURPOSE

The purpose of this study was to investigate working memory in adults who do (AWS) and do not (AWNS) stutter using a visual N-back task. Processes involved in an N-back task include encoding, storing, rehearsing, inhibition, temporal ordering, and matching.

METHODS

Fifteen AWS (11 males, 4 females; M = 23.27 years, SD = 5.68 years) and 15 AWNS (M = 23.47 years, SD = 6.21 years) were asked to monitor series of images and respond by pressing a "yes" button if the image they viewed was the same as the image one, two, or three trials back. Stimuli included images with phonologically similar (i.e., phonological condition) or phonologically dissimilar (i.e., neutral condition) names. Accuracy and manual reaction time (mRT) were analyzed.

RESULTS

No difference was found between AWS and AWNS in accuracy. Furthermore, both groups were more accurate and significantly faster in 1- followed by 2- followed by 3-back trials. Finally, AWNS demonstrated faster mRT in the phonological compared to neutral condition, whereas AWS did not.

CONCLUSION

Results from this study suggest different processing mechanisms between AWS and AWNS for visually presented phonologically similar stimuli. Specifically, a phonological priming effect occurred in AWNS but not in AWS, potentially due to reduced spreading activation and organization in the mental lexicon of AWS. However, the lack of differences between AWS and AWNS across all N-back levels does not support deficits in AWS in aspects of working memory targeted through a visual N-back task; but, these results are preliminary and additional research is warranted.

Effects of Cognitive Training Programs on Executive Function in Children and Adolescents with Autism Spectrum Disorder: A Systematic Review

BACKGROUND

Autism Spectrum Disorder is often associated with deficits in executive functions (EFs), which is contributing significantly to individuals with ASD's difficulties in conducting an independent life, particularly considering social skills. Technologies offer promising opportunities to structure EF intervention programs for children on the autistic spectrum.

METHODS

This study aimed to review the effectiveness of randomized controlled trials or quasi-experimental studies of EF interventions delivered to children and young people (up to 23 years old) with a diagnosis of ASD. A special focus was dedicated to document the effectiveness of computerized and non-computerized cognitive training on (1) EFs and on (2) ASD symptomatology and social skills. Of 2601 studies retrieved, 19 fulfilled the inclusion criteria.

RESULTS

Most of the interventions identified were effective in enhancing EFs and reducing symptoms in children and young people with ASD. Limited evidence is available on their generalization to untrained skills (i.e., social abilities) as well as long-term effects.

CONCLUSIONS

There is growing evidence for overall effectiveness of EF training, particularly when computerized. However, caution should be taken when interpreting these findings owing to methodological limitations, the minimal number of papers retrieved, and a small samples of included studies.

Effect of Cold Stress on Neurobehavioral and Physiological Parameters in Rats

Objective: Cold stress is an important current issue and implementing control strategies to limit its sometimes harmful effects is crucial. Cold is a common stressor that can occur in our work and our occupational or leisure time activities every day. There are substantial studies on the effects of chronic stress on memory and behavior, although, the cognitive changes and anxiety disorders that can occur after exposure to chronic intermittent cold stress are not completely characterized. Therefore, the present study was undertaken with an aim to investigate the effects of chronic intermittent cold stress on body weight, food intake and working memory, and to elucidate cold stress related anxiety disorders using cognitive and behavioral test batteries. Methods: We generated a cold stress model by exposing rats to chronic intermittent cold stress for 5 consecutive days and in order to test for the potential presence of sex differences, a comparable number of male and female rats were tested in the current study. Then, we measured the body weights, food intake and the adrenal glands weight. Working memory and recognition memory were assessed using the Y maze and the Novel Object Recognition (NOR) tasks. While, sex differences in the effects of chronic stress on behavior were evaluated by the elevated plus maze (EPM), open field maze (OF), and Marble burying (MB) tests. Results: We found that 2 h exposure to cold (4°C) resulted in an increase in the relative weight of the adrenal glands in male rats. Given the same chronic stress 5 days of cold exposure (2 h per day), increased weight gain in male rats, while females showed decreased food intake and no change in body weight. Both sexes successfully performed the Y maze and object recognition (OR) tasks, indicating intact spatial working memory performance and object recognition abilities in both male and female rats. In addition, we have shown that stress caused an increase in the level of anxiety in male rats. In contrast, the behavior of the female rats was not affected by cold exposure. Conclusion: Overall, the current results provide preliminary evidence that chronic intermittent cold stress model may not be an efficient stressor to female rats. Females exhibit resilience to cold exposure that causes an increase in the level of anxiety in male rats, which demonstrates that they are affected differently by stress and the gender is an important consideration in experimental design.

Sleep quality and memory function in healthy ageing

OBJECTIVE

To study the relationship between sleep quality and memory in healthy ageing.

METHODS

The study included 99 people older than 50 years (69 women and 30 men; mean age, 68.74 ± 7.18 years) with no associated diseases. Patients completed digital versions of the Word Learning (WL) and Visual Paired Associates (VPA) tests and the Pittsburgh Sleep Quality Index (PSQI) questionnaire to assess the quality of sleep.

RESULTS

PSQI score was negatively correlated with VPA and WL test performance. Performance in these 2 memory tests decreased in line with sleep quality. In addition, performance in VPA test was negatively correlated with subjective sleep quality, duration, and sleep disturbances. Performance on the WL test was negatively correlated with subjective sleep quality and efficiency. Participants' sex showed a weak effect on VPA performance and sleep latency.

CONCLUSIONS

Medical professionals working with elderly patients should take into consideration the effect of poor sleep quality on memory. Cognitive impairment in these patients may be a manifestation of a neuroendocrine imbalance due to a disrupted circadian rhythm. More research is needed to prove this hypothesis.

The Association between the Binding Processes of Working Memory and Vascular Risk Profile in Adults

Episodic buffer (EB), a key component of working memory, seems to have a rather complicated function as part of binding processes. Recent papers on the field claim that binding processes of working memory (WM) are assisted by attention and executive functions. On the same page, vascular pathology is gaining more ground as the main underlying cause for many brain pathologies. Hypercholesterolemia, hypertension, obesity, diabetes, lack of exercise and smoking are the most common risk factors that people of all ages suffer from and constitute the main vascular risk factors responsible for a possible decline in executive functions and attention. Thus, this research is an attempt to examine the relation between the binding functions of WM and the existence of vascular risk factors via a computerized test focusing on feature binding. The study comprised adults (n = 229) with and without vascular risk factors. The main tools used were a biomarker questionnaire and a feature binding test (FBT). The results showed that participants who report suffering from one or more vascular risk factors had significantly lower performance on specific subtasks of the FBT in comparison to the participants who were healthy. This allows us to assume that there might be a positive association between feature binding and a vascular risk profile in adults, and such a test could be a useful diagnostic tool for early cognitive impairment due to incipient vascular pathology.

Straying Off Course: The Negative Impact of Mind Wandering on Fine Motor Movements

The goal of this study was to examine how various degrees of perceptual decoupling during mind wandering affect fine motor control. We hypothesized that while under normal circumstances attention ensures an optimal control strategy that leads to accurate motor performance, during mind wandering the process becomes disrupted. In this study, we conducted a computer-based experiment with a tracking task. During mind wandering, motor movements were more erratic and less variable, indicative of reduced attentiveness to the continuous demands of the external task. Importantly, the deeper the reported mind wandering, the less accurate and less variable were the mouse movements, suggesting that perceptual decoupling may take place in a graded rather than in an all or nothing manner. Greater movement intermittency was associated with higher tracking accuracy, suggesting that more corrective movements toward a moving target were functional to task performance. Moreover, greater variance in velocity was negatively correlated with tracking accuracy. These findings suggest that periods of inattention to the task have a negative impact on fine motor movement control by making behavior unpredictable, providing support for the idea that there is a decoupling of sensory-motor processes during mind wandering.

Functional connectivity evidence for state-independent executive function deficits in patients with major depressive disorder

BACKGROUND

Persistent neurocognitive deficits are often associated with poor outcomes of major depressive disorder (MDD). Executive dysfunction is the most common cognitive deficit in MDD. However, it remains unclear which subcomponent of executive dysfunction is state-independent with distinct neural substrates.

METHODS

A comprehensive neurocognitive test battery was used to assess four subcomponents of executive function (working memory, inhibition, shifting, and verbal fluency) in 95 MDD patients and 111 matched healthy controls (HCs). After 6 months of paroxetine treatment, 56 patients achieved clinical remission (rMDD) and completed the second-time neurocognitive test. Network-based statistics analysis was utilized to explore the changes in functional connectivity (FC).

RESULTS

Compared with the HCs, all the four subcomponents of MDD patients were significantly impaired. After treatment, there was a significant improvement in working memory, inhibition, and verbal fluency in the rMDD group. And shifting and verbal fluency of the rMDD group remained impaired compared with the HCs. Fifteen functional connections were interrupted in the MDD group, and 11 connections remained in a disrupted state after treatment. Importantly, verbal fluency was negatively correlated with the disrupted FC between the right dorsal prefrontal cortex and the left inferior parietal lobule in patients with MDD and remitted MDD.

LIMITATIONS

The correlation analysis of the association between cognitive impairment and connectivity alterations precluded us from making causal inferences.

CONCLUSIONS

Verbal fluency is the potential state-independent cognitive deficit with distinct neural basis in patients with MDD.