Visuospatial Working Memory Task Research Articles

An experimental medicine study of the phosphodiesterase-4 inhibitor, roflumilast, on working memory-related brain activity and episodic memory in schizophrenia patients

RationaleSchizophrenia is associated with impairments in cognitive functioning yet there are no approved drugs to treat these deficits.ObjectivesBased on animal models, we investigated the potential for roflumilast, a selective inhibitor of phosphodiesterase type 4 (PDE4), to improve cognition, which may act by increasing intracellular cyclic adenosine monophosphate in brain regions underlying cognitive deficits in schizophrenia.MethodsThis study consisted of a randomised, double-blind, placebo-controlled, crossover design involving 15 schizophrenia patients. In 3 treatment periods, patients were given 8 days of placebo or one of the two doses of roflumilast (100 and 250 μg daily) with 14 days of washout between treatments. The primary endpoints were dorsolateral prefrontal cortex (DLPFC) activation during a visuospatial working memory task measured with fMRI on dosing day 8 and verbal memory and working memory performance change from baseline to day 8. Least square mean change scores were calculated for behavioural outcomes; fMRI data were analysed in SPM12 with bilateral DLPFC as regions of interest.ResultsVerbal memory was significantly improved under 250 μg roflumilast (effect size (ES) = 0.77) compared to placebo. fMRI analyses revealed that increasing dose of roflumilast was associated with reduction of bilateral DLPFC activation during working memory compared to placebo, although this was not statistically significant (ES = 0.31 for the higher dose). Working memory was not improved (ES = 0.03).ConclusionsResults support the mechanistic validation of potential novel strategies for improving cognitive dysfunction in schizophrenia and suggest that PDE4 inhibition may be beneficial for cognitive dysfunction in schizophrenia.Trial registrationNCT02079844.

Complex systems representing effective connectivity in patients with Type One diabetes mellitus.

BackgroundType 1 diabetes mellitus (T1D) affects the entire cellular network of the organism. Some patients develop cognitive disturbances due to the disease, but several authors have suggested that the brain develops compensatory mechanisms to minimize or prevent neuropsychological decline. The present study aimed to assess the effective connectivity underlying visuospatial working memory performance in young adults diagnosed with T1D using neuroimaging techniques (fMRI).MethodsFifteen T1D right-handed, young adults with sustained metabolic clinical stability and a control group matched by age, sex, and educational level voluntarily participated. All participants performed 2 visuospatial working memory tasks using a block design within an MRI scanner. Regions of interest and their signal values were obtained. Effective connectivity—by means of structural equations models—was evaluated for each group and task through maximum likelihood estimation, and the model with the best fit was chosen in each case.ResultsCompared to the control group, the patient group showed a significant reduction in brain activity in the two estimated networks (one for each group and task). The models of effective connectivity showed greater brain connectivity in healthy individuals, as well as a more complex network. T1D patients showed a pattern of connectivity mainly involving the cerebellum and the red nucleus. In contrast, the control group showed a connectivity network predominantly involving brain areas that are typically activated while individuals are performing working memory tasks.ConclusionOur results suggest a specific effective connectivity between the cerebellum and the red nucleus in T1D patients during working memory tasks, probably reflecting a compensatory mechanism to fulfill task demands.

Bilingualism and working memory performance: Evidence from a large-scale online study.

The bilingual executive advantage (BEA) hypothesis has attracted considerable research interest, but the findings are inconclusive. We addressed this issue in the domain of working memory (WM), as more complex WM tasks have been underrepresented in the previous literature. First, we compared early and late bilingual vs. monolingual WM performance. Second, we examined whether certain aspects of bilingual experience, such as language switching frequency, are related to bilinguals’ WM scores. Our online sample included 485 participants. They filled in an extensive questionnaire including background factors such as bilingualism and second language (L2) use, and performed 10 isomorphic verbal and visuospatial WM tasks that yielded three WM composite scores (visuospatial WM, verbal WM, n-back). For verbal and visuospatial WM composites, the group comparisons did not support the BEA hypothesis. N-back analysis showed an advantage of late bilinguals over monolinguals and early bilinguals, while the latter two groups did not differ. This between-groups analysis was followed by a regression analysis relating features of bilingual experience to n-back performance, but the results were non-significant in both bilingual groups. In sum, group differences supporting the BEA hypothesis were limited only to the n-back composite, and this composite was not predicted by bilingualism-related features. Moreover, Bayesian analyses did not give consistent support for the BEA hypothesis. Possible reasons for the failure to find support for the BEA hypothesis are discussed.

Effect of cognitive and executive functions on perception of quality of life of cognitively normal elderly people dwelling in residential aged care facilities in Sri Lanka

BackgroundAlthough cognitive functions affect the health related quality of life (QoL), the relationship between perceived QoL and cognition including executive functions has not been studied adequately. Available studies show moderate to weak correlations. We evaluated the association of cognition and executive functions, namely working memory (WM) and inhibitory control (IC) with the perceived QoL of a sample of elderly people dwelling in residential aged care facilities (RACFs) in Southern Province of Sri Lanka.MethodsCognition was assessed using Mini-Mental State Examination (MMSE), while verbal WM (VWM), visuo-spatial WM (VSWM) and IC (interference control, inhibition of pre potent and ongoing responses) were assessed using VWM, VSWM tasks, colour word Stroop (CWS), go/no-go (GNG) and stop signal (SS) tasks respectively. WHOQoL-Bref (Total score and domain scores) were used to assess QoL. The relationship was analysed using Pearson correlation and hierarchical multiple regression analysis.ResultsStudy included 237 elderly people with a mean age of 71.11 ± 6.44 years. Participants scored the highest in the domain of environment (63.48 ± 10.63) and lowest in the domain of social relationships (55.43 ± 21.84) of QoL. Psychological health domain positively correlated with MMSE, VSWM and VWM scores and negatively correlated with CWS, SS and GNG task errors. Both physical health domain and total QoL demonstrated positive correlations with MMSE, VSWM and VWM scores, while negative correlations were observed with CWS task errors. Social relationships domain demonstrated a significant positive correlation with VSWM score. Environment domain positively correlated with MMSE, VSWM and VWM scores and negatively correlated with CWS and SS task errors. All were significant but weak correlations. When controlled for covariates, such as educational status, physical activity and marital status, cognition was a predictor of the domain of environment of QoL, while executive functions were not predictors of total QoL and domains of QoL.ConclusionCognition and executive functions weakly but significantly correlated with different domains of QoL. Only the level of cognition measured by MMSE was a predictor of the domain of environment of QoL and executive functions were not predictors of total QoL and domains of QoL in elderly people with normal cognitive functions dwelling in RACFs.

Sex difference in brain CB1 receptor availability in man

The endocannabinoid system (ECS) has a widespread neuromodulatory function in the central nervous system and is involved in important aspects of brain function including brain development, cortical rhythms, plasticity, reward, and stress sensitivity. Many of these effects are mediated via the cannabinoid CB1 receptor (CB1R) subtype. Animal studies convincingly show an interaction between the ECS and sex hormones, as well as a sex difference of higher brain CB1R in males. Human in vivo studies of sex difference have yielded discrepant findings.Gender differences in CB1R availability were investigated in vivo in 11 male and 11 female healthy volunteers using a specific CB1R tracer [18F]FMPEP-d2 and positron emission tomography (PET). Regional [18F]FMPEP-d2 distribution volume was used as a proxy for CB1R availability. In addition, we explored whether CB1R availability is linked to neuropsychological functioning.Relative to females, CB1R availability was on average 41% higher in males (p = 0.002) with a regionally specific effect larger in the posterior cingulate and retrosplenial cortices (p = 0.001). Inter-subject variability in CB1R availability was similar in both groups. Voxel-based analyses revealed an inverse association between CB1R availability and visuospatial working memory task performance in both groups (p < 0.001).A CB1R sex difference with a large effect size was observed and should be considered in the design of CB1R-related studies on neuropsychiatric disorders. The behavioural correlates and clinical significance of this difference remain to be further elucidated, but our studies suggest an association between CB1R availability and working memory.

Neural correlates of action video game experience in a visuospatial working memory task

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

Disentangling common from specific processing across tasks using task potency

When an individual engages in a task, the associated evoked activities build upon already ongoing activity, shaped by an underlying functional connectivity baseline (Fox et al., 2009; Smith et al., 2009; Tavor et al., 2016). Building on the idea that rest represents the brain's full functional repertoire, we here incorporate the idea that task-induced functional connectivity modulations ought to be task-specific with respect to their underlying resting state functional connectivity. Various metrics such as clustering coefficient or average path length have been proposed to index processing efficiency, typically from single fMRI session data. We introduce a framework incorporating task potency, which provides direct access to task-specificity by enabling direct comparison between task paradigms. In particular, to study functional connectivity modulations related to cognitive involvement in a task we define task potency as the amplitude of a connectivity modulation away from its baseline functional connectivity architecture as observed during a resting state acquisition. We demonstrate the use of our framework by comparing three tasks (visuo-spatial working memory, reward processing, and stop signal task) available within a large cohort. Using task potency, we demonstrate that cognitive operations are supported by a set of common within-network interactions, supplemented by connections between large-scale networks in order to solve a specific task.

A novel method for assessing patients with schizophrenia and their first-degree relatives by increasing cognitive load of visuo-spatial working memory.

In patients with schizophrenia, social and functional outcome is determined by the cognitive impairment. Assessment of visuo-spatial working memory (VSWM) which can simulate the day-to-day activities by simultaneous involvement of various elements of working memory may reflect disorganized thinking and fragmentation of thoughts in schizophrenia. Thirty-six patients with schizophrenia, 29 first-degree relatives of patients, and 25 healthy controls performed a VSWM task with three memory loads (comprising three pairs, six pairs, and eight pairs of abstract pictures). They were administered Hindi version of the Mini Mental State Examination, Scale for the Assessment of Negative Symptoms and Scale for the Assessment of Positive Symptoms, and Edinburgh handedness inventory. Patients (mean age 27.29(5.98) years) committed significantly higher number of errors than healthy controls (mean age 26.76(6.08) years) in load 3 (P=0.012) and total errors (P=0.018). Within all the groups, errors in load 3 were significantly higher than in load 2. Significant correlation was observed between years of education (r=-0.388, P=0.021), treatment duration (r=-0.880, P<0.001), negative symptoms scores (r=0.345, P=0.039), and the total errors committed by patients. Visuo-spatial working memory was impaired in schizophrenia with increasing cognitive load with no difference in search time between the groups.

Integrated assessment of visual perception abnormalities in psychotic disorders and relationship with clinical characteristics.

The visual system is recognized as an important site of pathology and dysfunction in schizophrenia. In this study, we evaluated different visual perceptual functions in patients with psychotic disorders using a potentially clinically applicable task battery and assessed their relationship with symptom severity in patients, and with schizotypal features in healthy participants. Five different areas of visual functioning were evaluated in patients with schizophrenia and schizoaffective disorder (n = 28) and healthy control subjects (n = 31) using a battery that included visuospatial working memory (VSWM), velocity discrimination (VD), contour integration, visual context processing, and backward masking tasks. The patient group demonstrated significantly lower performance in VD, contour integration, and VSWM tasks. Performance did not differ between the two groups on the visual context processing task and did not differ across levels of interstimulus intervals in the backward masking task. Performances on VSWM, VD, and contour integration tasks were correlated with negative symptom severity but not with other symptom dimensions in the patient group. VSWM and VD performances were also correlated with negative sychizotypal features in healthy controls. Taken together, these results demonstrate significant abnormalities in multiple visual processing tasks in patients with psychotic disorders, adding to the literature implicating visual abnormalities in these conditions. Furthermore, our results show that visual processing impairments are associated with the negative symptom dimension in patients as well as healthy individuals.

Evidencing the developmental shift from reactive to proactive control in early childhood and its relationship to working memory

As they age, children tend to get more effective at regulating their behavior in complex situations; this improvement in cognitive control is often interpreted as a shift from predominantly reactive control to proactive control. There are three issues with this interpretation. First, hard evidence is lacking that younger children actually rely on reactive control. Second, the precise age range when such a shift would occur is still unclear. Third, the reasons for this shift have not been explored. In the current study, we tested the hypothesis that children under 5 years of age do rely on reactive control, that they progressively shift to proactive control with age, and that this shift is related to increases in working memory capacity (which is necessary for proactive control). Children aged 4 to 7 years performed a cognitive control task, the AX-CPT (AX–Continuous Performance Task), as well as verbal and visuospatial working memory tasks. Using the paradigmatic AX-CPT in this age range allowed us to observe, for the first time, an actual reactive pattern in children under 5 years of age. There was a progressive shift from reactive control to proactive control, with an estimated turning point between 5 and 6 years of age. The effect of age on proactive control was essentially shared with working memory capacity, confirming that these two cognitive processes develop in tandem.

Correction: fNIRS measurement of cortical activation and functional connectivity during a visuospatial working memory task.

[This corrects the article DOI: 10.1371/journal.pone.0201486.].

The enhanced cognitive interview: could individual differences in visuo-spatial working memory explain differences in recalling an event?

ABSTRACTThe Enhanced Cognitive Interview (ECI) is one of the most useful witness interviews, consisting of 5 techniques (context reinstatement: CR; report everything: RE, mental imagery: MI, change order: CO and change of perspectives: CP) aimed at increasing both the quantity and the quality of elements recalled. All the techniques require mental imagery skills. The present study investigates the relationship between forward and backward visuo-spatial working memory (VSWM) and correct elements recalled through the ECI with respect to its techniques. 99 college students (48 males) watched a color videotape of a fictional crime and performed a visuo-spatial working memory task. The following day they were interviewed about what they had seen. Results showed that high forward VSWM capacity has a role in favoring the total amount of correct information recalled, specifically in the MI technique. This suggests that maintaining and processing mood-related contents in VSWM is easier for individuals with high working memory skills.

Early Cannabis Use and Neurocognitive Risk: A Prospective Functional Neuroimaging Study

BackgroundRetrospective neuroimaging studies have suggested an association between early cannabis onset and later neurocognitive impairment. However, these studies have been limited in their ability to distinguish substance use risk factors from cannabis-induced effects on neurocognition. We used a prospective cohort design to test whether neurocognitive differences preceded cannabis onset (substance use risk model) and if early cannabis use was associated with poorer neurocognitive development (cannabis exposure model). MethodsParticipants (N = 85) completed a visuospatial working memory task during functional magnetic resonance imaging and multiple cognitive assessments (Wechsler Intelligence Scale for Children-IV, Cambridge Neuropsychological Test Automated Battery) at 12 years of age, before any reported cannabis use (baseline), and at 15 years of age (follow-up: N = 85 cognitive assessments, n = 67 neuroimaging). By follow-up, 22 participants reported using cannabis and/or failed a Δ9-tetrahydrocannabinol urine screen (users). ResultsAt baseline, group differences supported a risk model. Those who would initiate cannabis use by 15 years of age had activation differences in frontoparietal (increased) and visual association (decreased) regions and poorer executive planning scores (Stockings of Cambridge) compared with noninitiators. Limited support was found for a cannabis exposure model. At follow-up, activation in the cuneus displayed a significant cannabis dose-response relationship, although neither cannabis dose nor cuneus activation was associated with cognitive performance. ConclusionsThe purported neurocognitive effects of early cannabis onset may not be due to cannabis initiation alone but also driven by limitations or late development of neurocognitive systems predictive of substance use. In addition, more prolonged cannabis exposure may be required to observe the cognitive effects of early cannabis onset.

Square-stepping Exercise For Older Adults With Chronic Disease To Improve Cognition and Mobility

Square-stepping exercise (SSE) is a visuospatial working memory task with a cued stepping response that improves mobility and cognition in older adults.PURPOSE: To determine if a SSE intervention improves cognitive and mobility in older adults with chronic disease (i.e., knee osteoarthritis [KOA]; t

The Validity of Functional Near-Infrared Spectroscopy Recordings of Visuospatial Working Memory Processes in Humans.

Functional near infrared spectroscopy (fNIRS) is increasingly used for investigating cognitive processes. To provide converging evidence for the validity of fNIRS recordings in cognitive neuroscience, we investigated functional activation in the frontal cortex in 43 participants during the processing of a visuospatial working memory (WM) task and a sensory duration discrimination (DD) task functionally unrelated to WM. To distinguish WM-related processes from a general effect of increased task demand, we applied an adaptive approach, which ensured that subjective task demand was virtually identical for all individuals and across both tasks. Our specified region of interest covered Brodmann Area 8 of the left hemisphere, known for its important role in the execution of WM processes. Functional activation, as indicated by an increase of oxygenated and a decrease of deoxygenated hemoglobin, was shown for the WM task, but not in the DD task. The overall pattern of results indicated that hemodynamic responses recorded by fNIRS are sensitive to specific visuospatial WM capacity-related processes and do not reflect a general effect of increased task demand. In addition, the finding that no such functional activation could be shown for participants with far above-average mental ability suggested different cognitive processes adopted by this latter group.

Dynamic frontotemporal systems process space and time in working memory.

How do we rapidly process incoming streams of information in working memory, a cognitive mechanism central to human behavior? Dominant views of working memory focus on the prefrontal cortex (PFC), but human hippocampal recordings provide a neurophysiological signature distinct from the PFC. Are these regions independent, or do they interact in the service of working memory? We addressed this core issue in behavior by recording directly from frontotemporal sites in humans performing a visuospatial working memory task that operationalizes the types of identity and spatiotemporal information we encounter every day. Theta band oscillations drove bidirectional interactions between the PFC and medial temporal lobe (MTL; including the hippocampus). MTL theta oscillations directed the PFC preferentially during the processing of spatiotemporal information, while PFC theta oscillations directed the MTL for all types of information being processed in working memory. These findings reveal an MTL theta mechanism for processing space and time and a domain-general PFC theta mechanism, providing evidence that rapid, dynamic MTL–PFC interactions underlie working memory for everyday experiences.

Dopamine D2 agonist affects visuospatial working memory distractor interference depending on individual differences in baseline working memory span.

The interplay of dopaminergic striatal D1-D2 circuits is thought to support working memory (WM) by selectively filtering information that is to be remembered versus information to be ignored. To test this theory, we conducted an experiment in which healthy participants performed a visuospatial working memory (VSWM) task after ingesting the D2-receptor agonist cabergoline (or placebo), in a randomized, double-blinded, crossover design. Results showed greater interference from distractors under cabergoline, particularly for individuals with higher baseline dopamine (indicated by WM span). These findings support computational theories of striatal D1-D2 function during WM encoding and distractor-filtering, and provide new evidence for interactive cortico-striatal systems that support VSWM capacity and their dependence on WM span.

Writing abilities and the role of working memory in children with symptoms of attention deficit and hyperactivity disorder

ABSTRACTThe writing abilities of children with ADHD symptoms were examined in a simple dictation task, and then in two conditions with concurrent verbal or visuospatial working memory (WM) loads. The children with ADHD symptoms generally made more spelling mistakes than controls, and the concurrent loads impaired their performance, but with partly different effects. The concurrent verbal WM task prompted an increase in the phonological errors, while the concurrent visuospatial WM task prompted more non-phonological errors, matching the Italian phonology, but not the Italian orthography. In the ADHD group, the children proving better able to cope with a concurrent verbal WM load had a better spelling performance too. The ADHD and control groups had a similar handwriting speed, but the former group’s writing quality was poorer. Our results suggest that WM supports writing skills, and that children with ADHD symptoms have general writing difficulties, but strength in coping with concurrent verbal information may support their spelling performance.

Age-related differences in the use of spatial and categorical relationships in a visuo-spatial working memory task.

Research examining object identity and location processing in visuo-spatial working memory (VSWM) has yielded inconsistent results on whether age differences exist in VSWM. The present study investigated whether these inconsistencies may stem from age-related differences in VSWM sub-processes, and whether processing of component VSWM information can be facilitated. In two experiments, younger and older adults studied 5 × 5 grids containing five objects in separate locations. In a continuous recognition paradigm, participants were tested on memory for object identity, location, or identity and location information combined. Spatial and categorical relationships were manipulated within grids to provide trial-level facilitation. In Experiment 1, randomizing trial types (location, identity, combination) assured that participants could not predict the information that would be queried. In Experiment 2, blocking trials by type encouraged strategic processing. Thus, we manipulated the nature of the task through object categorical relationship and spatial organization, and trial blocking. Our findings support age-related declines in VSWM. Additionally, grid organizations (categorical and spatial relationships), and trial blocking differentially affected younger and older adults. Younger adults used spatial organizations more effectively whereas older adults demonstrated an association bias. Our finding also suggests that older adults may be less efficient than younger adults in strategically engaging information processing.

Effects of sleep deprivation on component processes of working memory in younger and older adults

Working memory (WM) has been described as a multicomponent process, comprised of the following: attention-driven encoding, maintenance and rehearsal of information, and encoding to and retrieval from episodic memory. Impairments can affect higher-order cognitive processes and many everyday functions. The impact of sleep changes on these cognitive processes across the life span needs to be investigated. The aim of the current study is to examine the effects of sleep deprivation on component processes of WM, comparing younger and older adults across verbal and visuospatial modalities. Thirty-one younger adults (19-38 years) and 33 older adults (59-82 years) attended two counterbalanced sleep protocols: a regular night of sleep followed by testing the next day (normally rested condition), and 36 hr of total sleep deprivation (TSD), followed by testing (TSD condition). Participants completed matched versions of verbal and visuospatial WM tasks across conditions. Younger adults significantly outperformed older adults on encoding and displacement component processes, for both verbal and visuospatial WM. Following TSD, younger adults showed a significantly larger drop compared with older adults in verbal encoding and in visuospatial displacement. A main effect of condition was observed for verbal displacement. Differences were observed in the performance of younger and older adults on component processes of WM following TSD. This suggests that TSD can have differential effects on each component process when younger and older adults are compared, in both verbal and visuospatial tasks. Understanding this profile of changes is important for the development of possible compensatory strategies or interventions and the differentiation of clinical and healthy populations.