N-back Research Articles

Disrupted cognitive network revealed by task-induced brain entropy in schizophrenia.

Brain entropy (BEN), which measures the amount of information in brain activity, provides a novel perspective for evaluating brain function. Recent studies using resting-state functional magnetic resonance imaging (fMRI) have shown that BEN during rest can help characterize brain function alterations in schizophrenia (SCZ). However, there is a lack of research on BEN using task-evoked fMRI to explore task-dependent cognitive deficits in SCZ. In this study, we evaluate whether the reduced working memory (WM) capacity in SCZ is possibly associated with dynamic changes in task BEN during tasks with high cognitive demands. We analyzed data from 15 patients with SCZ and 15 healthy controls (HC), calculating task BEN from their N-back task fMRI scans. We then examined correlations between task BEN values, clinical symptoms, 2-back task performance, and neuropsychological test scores. Patients with SCZ exhibited significantly reduced task BEN in the cerebellum, hippocampus, parahippocampal gyrus, thalamus, and the middle and superior frontal gyrus (MFG and SFG) compared to HC. In HC, significant positive correlations were observed between task BEN and 2-back accuracy in several brain regions, including the MFG and SFG; such correlations were absent in patients with SCZ. Additionally, task BEN was negatively associated with scores for both positive and negative symptoms in areas including the parahippocampal gyrus among patients with SCZ. In conclusion, our findings indicate that a reduction in BEN within prefrontal and hippocampal regions during cognitively demanding tasks may serve as a neuroimaging marker for SCZ.

Acute Aerobic Exercise Intensity on Working Memory and Vigilance After Nap Deprivation: Effects of Low-Intensity Deserve Attention.

Napping deprivation in habitual nappers leads to cognitive impairment. The ameliorative effect of acute aerobic exercise has been demonstrated for this post-cognitive impairment. However, it is still unclear which intensity of aerobic exercise is the most effective and how long this improvement can be sustained. Fifty-eight healthy adults with a chronic napping habit were randomly assigned to four intervention groups after undergoing nap deprivation: a sedentary control group, a low-intensity exercise group (50-59% maximum heart rate, HRmax), a moderate-intensity exercise group (60-69% HRmax), and a high-intensity exercise group (70-79% HRmax). Working memory (N-back task), vigilance (Psychomotor Vigilance Task, PVT), and response inhibitory capacity (Go/NoGo task) were measured. Regression analyses showed a quadratic trend between exercise intensity and working memory reaction time and accuracy (F =3.297-5.769, p < 0.05, R2 =10.7-18.9%). The effects of exercise were optimal at low-intensity. There was a significant quadratic trend between exercise intensity and PVT lapse (F =4.314, p =0.042, R² =7.2%). The effect of exercise increased with higher intensity. Prolonged observation found that the effect of low-intensity exercise on working memory was maintained for 2 hours. The effect of low-intensity exercise might be underestimated. Low-intensity exercise significantly improved working memory performance, and the effects could be maintained throughout the afternoon. In contrast, the effects of high-intensity exercise were unlikely to be maintained and might even have negative effects. Future researchers can broaden the categories of participants to enhance the external validity and collect diverse physiological indicators to explore related physiological mechanisms.

Neural and Behavioral Correlates of Binge Eating in 9- to 10-Year-Old Children

This observational study compared children with and without binge eating (BE) on biobehavioral measures of reward responsiveness, inhibitory control, and emotion processes, while accounting for the impact of weight. Children aged 9 to 10 years completed the baseline wave of the Adolescent Brain Cognitive Development Study (316 with BE; 7,681 without BE [no-BE]). The prevalence of binge-eating disorder in the BE group was 17.0%; clinically significant internalizing and externalizing symptoms were endorsed by 8.5% and 4.5% of the sample, respectively. The monetary incentive delay (MID) task, stop signal task (SST), and emotional N-Back (EN-Back) task were administered during neuroimaging. Analyses assessed effects of group (BE vs no-BE) on task performance and corresponding neural signal in regions of interest (ROIs). Weight status was evaluated as a covariate and as a moderator of effects. Adjusting for weight status, the BE group (vs no-BE) group showed lower activation during anticipation of reward, specifically large reward (vs no reward), in the composite ROI consisting of the dorsal striatum, nucleus accumbens, orbital frontal gyrus, amygdala, and insula. Groups did not differ significantly in other behavioral or neural outcomes. No interactions between group and weight status were observed. Blunted anticipatory responses to monetary reward were associated with binge eating during peri-adolescence and may play a role in binge eating pathophysiology. Results challenge prior findings in BE that may be confounded by weight, and highlight the importance of future prospective research across binge-eating disorder stage of illness.

Differential Effects of Continuous Theta Burst Stimulation over the Bilateral and Unilateral Cerebellum on Working Memory.

Recent functional MRI studies have implicated the cerebellum in working memory (WM) alongside the prefrontal cortex. Some findings indicate that the right cerebellum is activated during verbal tasks, while the left is engaged during visuospatial tasks, suggesting cerebellar lateralization in WM function. The cerebellum could be a potential target for non-invasive brain stimulation (NIBS) to enhance WM function in cognitive disorders. However, the comprehensive influence of cerebellar lateralization on different types of WM and the effect of stimulation over the unilateral or bilateral cerebellum remain uncertain. This study was to investigate the cerebellum's functional lateralization and its specific impact on various aspects of WM in a causal manner using unilateral or bilateral cerebellar continuous theta burst stimulation (cTBS), a form of inhibitroy NIBS. Twenty-four healthy participants underwent four sessions of cTBS targeting the left, right, or bilateral Crus I of the cerebellum, or a sham condition, in a controlled cross-over design. WM performance was assessed pre- and post-stimulation using neuropsychological tests, including the 3-back task, spatial WM task, and digit span task. Results indicated that cTBS over the bilateral and right cerebellum both led to a greater improvement in 3-back task performance compared to sham stimulation. Additionally, active cTBS over the bilateral cerebellum yielded better performance in the spatial WM task than sham stimulation. However, no significant differences were observed between stimulation conditions for the auditory digit span task. This study may provide novel causal evidence highlighting the specific involvement of the right and bilateral cerebellum in various types of WM. Specifically, the right cerebellum appears crucial for updating and tracking 3-back WM content, while spatial WM processes require the coordinated engagement of both cerebellar hemispheres.

Exaggerated frontoparietal control over cognitive effort-based decision-making in young women with anorexia nervosa.

Effortful tasks are generally experienced as costly, but the value of work varies greatly across individuals and populations. While most mental health conditions are characterized by amotivation and effort avoidance, individuals with anorexia nervosa (AN) persistently engage in effortful behaviors that most people find unrewarding (food restriction, excessive exercise). Current models of AN differentially attribute such extreme weight-control behavior to altered reward responding and exaggerated cognitive control. In a novel test of these theoretical accounts, we employed an established cognitive effort discounting paradigm in combination with fMRI in young acutely underweight female patients with AN (n = 48) and age-matched healthy controls (HC; n = 48). Contrary to the hypothesis that individuals with AN would experience cognitive effort (operationalized as N-back task performance) as less costly than HC participants, groups did not differ in the subjective value (SV) of discounted rewards or in SV-related activation of brain regions involved in reward valuation. Rather, all group differences in both behavior (superior N-back performance in AN and associated effort ratings) and fMRI activation (increased SV-related frontoparietal activation during decision-making in AN even for easier choices) were more indicative of increased control. These findings suggest that while effort discounting may be relatively intact in AN, effort investment is high both when performing demanding tasks and during effort-based decision-making; highlighting cognitive overcontrol as an important therapeutic target. Future research should establish whether exaggerated control during effort-based decision-making persists after weight-recovery and explore learning the value of effort in AN with tasks involving disorder-relevant effort demands and rewards.

Using SIM-TLX to investigate the potential impacts on cognitive load while undertaking tasks in a virtual workplace

PurposeThe ability to measure cognitive load in the workplace provides several opportunities to improve workplace learning. In recent years, virtual reality (VR) has seen an increase in use for training and learning applications due to improvements in technology and reduced costs. This study aims to focus on the use of simulation task load index (SIM-TLX), a recently developed self-reported measure of cognitive load for virtual environments to measure cognitive load while undertaking tasks in different environments.Design/methodology/approachThe authors conducted a within-subject design experiment involving 14 participants engaged in digit-recall n-back tasks (1-back and 2-back) in two VR environments: a neutral grey environment and a realistic industrial ozone facility. Cognitive load was then assessed using the SIM-TLX.FindingsThe findings revealed higher task difficulty for the 2-back task due to higher mental demand. Furthermore, a notable interaction emerged between cognitive load and different virtual environments.Research limitations/implicationsThis study relied solely on an n-back task and SIM-TLX self-report measure to assess cognitive load. Future studies should consider including ecologically valid tasks and physiological measurement tools such as eye-tracking to measure cognitive load.Practical implicationsIdentifying cognitive workload sources during VR tasks, especially in complex work environments, is considered beneficial to the application of VR training aimed at improving workplace learning.Originality/valueThis study provides unique insights into measuring cognitive load from various sources as defined by the SIM-TLX sub-scales to investigate the impact of simulated workplace environments.

Investigating the relationship between CSAT scores and prefrontal fNIRS signals during cognitive tasks using a quantum annealing algorithm

Academic achievement is a critical measure of intellectual ability, prompting extensive research into cognitive tasks as potential predictors. Neuroimaging technologies, such as functional near-infrared spectroscopy (fNIRS), offer insights into brain hemodynamics, allowing understanding of the link between cognitive performance and academic achievement. Herein, we explored the association between cognitive tasks and academic achievement by analyzing prefrontal fNIRS signals. A novel quantum annealer (QA) feature selection algorithm was applied to fNIRS data to identify cognitive tasks correlated with CSAT scores. Twelve features (signal mean, median, variance, peak, number of peaks, sum of peaks, range, minimum, kurtosis, skewness, standard deviation, and root mean square) were extracted from fNIRS signals at two time windows (10- and 60-s) to compare results from various feature variable conditions. The feature selection results from the QA-based and XGBoost regressor algorithms were compared to validate the former’s performance. In a two-step validation process using multiple linear regression models, model fitness (adjusted R2) and model prediction error (RMSE) values were calculated. The quantum annealer demonstrated comparable performance to classical machine learning models, and specific cognitive tasks, including verbal fluency, recognition, and the Corsi block tapping task, were correlated with academic achievement. Group analyses revealed stronger associations between Tower of London and N-back tasks with higher CSAT scores. Quantum annealing algorithms have significant potential in feature selection using fNIRS data, and represents a novel research approach. Future studies should explore predictors of academic achievement and cognitive ability.

A ventromedial visual cortical ‘Where’ stream to the human hippocampus for spatial scenes revealed with magnetoencephalography

The primate including the human hippocampus implicated in episodic memory and navigation represents a spatial view, very different from the place representations in rodents. To understand this system in humans, and the computations performed, the pathway for this spatial view information to reach the hippocampus was analysed in humans. Whole-brain effective connectivity was measured with magnetoencephalography between 30 visual cortical regions and 150 other cortical regions using the HCP-MMP1 atlas in 21 participants while performing a 0-back scene memory task. In a ventromedial visual stream, V1–V4 connect to the ProStriate region where the retrosplenial scene area is located. The ProStriate region has connectivity to ventromedial visual regions VMV1–3 and VVC. These ventromedial regions connect to the medial parahippocampal region PHA1–3, which, with the VMV regions, include the parahippocampal scene area. The medial parahippocampal regions have effective connectivity to the entorhinal cortex, perirhinal cortex, and hippocampus. In contrast, when viewing faces, the effective connectivity was more through a ventrolateral visual cortical stream via the fusiform face cortex to the inferior temporal visual cortex regions TE2p and TE2a. A ventromedial visual cortical ‘Where’ stream to the hippocampus for spatial scenes was supported by diffusion topography in 171 HCP participants at 7 T.

EEG-CogNet: A deep learning framework for cognitive state assessment using EEG brain connectivity

The assessment of cognitive states such as workload, attention, and fatigue is crucial in cognitive science and human performance fields due to its significant impact on work efficiency and decision-making. This paper introduces a deep learning framework for cognitive state assessment using Electroencephalogram (EEG) brain connectivity. The framework was evaluated using EEG data from 26 participants through three computer-based tasks: the Dual N-Back Task, Visual Search Task, and Continuous Performance Task, each designed to induce varying levels of cognitive workload, attention, and fatigue, respectively. A comprehensive dataset was meticulously compiled, including physiological, behavioral, and subjective data to ensure robust analyses. The EEG data underwent rigorous pre-processing and feature extraction processes, focusing on brain connectivity metrics such as Coherence and Phase-Locking Value across multiple frequency bands and employing three neural network architectures: Convolutional Neural Networks (CNN), Graph Convolutional Networks (GCN), and Convolutional Long Short-Term Memory networks (ConvLSTM) for classification. The proposed work achieved classification accuracies of 96.53% for workload, 98.40% for attention, and 97.86% for fatigue in the combined frequency bands. The study’s findings underscore the potential of EEG-based methods for non-invasive cognitive state monitoring. By addressing existing limitations such as small sample sizes and task-specific models, this research enhances the generalizability and applicability of EEG-based cognitive assessments. The implications of these advancements are significant for fields requiring continuous cognitive monitoring, such as defense, healthcare, and high-risk operational environments.

Evidence for separate backward recall and n-back working memory factors: a large-scale latent variable analysis

ABSTRACT Multiple studies have explored the factor structure of working memory (WM) tasks, yet few have done so controlling for both the domain and category of the memory items in a single study. In the current pre-registered study, we conducted a large-scale latent variable analysis using variant forms of n-back and backward recall tasks to test whether they measured a single underlying construct, or were distinguished by stimuli-, domain-, or paradigm-specific factors. Exploratory analyses investigated how the resulting WM factor(s) were linked to fluid intelligence. Participants (N = 703) completed a fluid reasoning test and multiple n-back and backward recall tasks containing memoranda that varied across (spatial or verbal material) and within (verbal digits or letters) domain, allowing the variance specific to task content and paradigm to be assessed. Two distinct but related backward recall and n-back constructs best captured the data, in comparison to other plausible model constructions (single WM factor, two-factor domain, and three-factor materials models). Common variance associated with WM was a stronger predictor of fluid reasoning than a residual n-back factor, but the backward recall factor predicted fluid reasoning as strongly as the common WM factor. These data emphasise the distinctiveness between backward recall and n-back tasks.

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.

A Multimodal Magnetic Resonance Imaging Study on Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Feasibility and Clinical Correlation.

Background/Objectives: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a neurological disorder characterized by post-exertional malaise. Despite its clinical relevance, the disease mechanisms of ME/CFS are not fully understood. The previous studies targeting brain function or metabolites have been inconclusive in understanding ME/CFS complexity. We combined single-voxel magnetic resonance spectroscopy (SV-MRS) and functional magnetic resonance imaging (fMRI). Our objectives were to examine the feasibility of the multimodal MRI protocol, identify possible differences between ME/CFS and healthy controls (HCs), and relate MRI findings with clinical symptoms. Methods: We enrolled 18 female ME/CFS participants (mean age: 39.7 ± 12.0 years) and five HCs (mean age: 45.6 ± 14.5 years). SV-MRS spectra were acquired from three voxels of interest: the anterior cingulate gyrus (ACC), brainstem (BS), and left dorsolateral prefrontal cortex (L-DLPFC). Whole-brain fMRI used n-back task testing working memory and executive function. The feasibility was assessed as protocol completion rate and time. Group differences in brain metabolites and fMRI activation between ME/CFS and HCs were compared and correlated with behavioral and symptom severity measurements. Results: The completion rate was 100% regardless of participant group without causing immediate fatigue. ME/CFS appeared to show a higher N-Acetylaspartate in L-DLPFC compared to HCs (OR = 8.49, p = 0.040), correlating with poorer fatigue, pain, and sleep quality scores (p's = 0.001-0.015). An increase in brain activation involving the frontal lobe and the brainstem was observed in ME/CFS compared to HCs (Z > 3.4, p's < 0.010). Conclusions: The study demonstrates the feasibility of combining MRS and fMRI to capture neurochemical and neurophysiological features of ME/CFS in female participants. Further research with larger cohorts of more representative sampling and follow-ups is needed to validate these apparent differences between ME/CFS and HCs.

Designing Novel Physiologic Monitor Displays for Combat Medics.

Combat medics who are responsible for the care of injured warfighters face challenges from their reliance on medical alarms that exceed the noise levels recommended by the WHO. This is because the elevated noise levels in military facilities, particularly from vehicular units and weaponry, compromise the combat medics' effectiveness and attentiveness to medical alarms. We previously designed a graphical ("configural") display to communicate patients' vital signs and found that when the configural display and traditional numerical display were concurrently presented to participants, it produced the fastest identification of patient vital signs and triggered the fewest number of alarms. This study used eye tracking to assess how participants direct visual attention to and engage with concurrently presented numerical and configural vital sign displays. We recruited 30 undergraduate students with normal hearing and vision for this study. Subjects were tasked with monitoring a simulated patient's vital signals using simultaneously presented numerical and configural vital sign displays. Concurrently, they performed an N-back task to simulate the multitasking required in a military environment. We manipulated the eccentricity and display position of the numerical and configural displays through 4 orientations, with each orientation being used in a monitoring block lasting 12 minutes. Continuous eye tracking was utilized to collect physiological data about participant display preference. We used eye tracking to analyze several metrics: Total display viewing time, total viewing time percentage, number of dwells (groups of eye fixations), mean fixations per dwell, and fixation patterns during an emergency event. Participants spent more time looking at the configural display than the numerical display during nominal monitoring and emergency events. During emergencies, the percentage of time individuals spent looking at the configural display increased from 30 to 50%, while there was no corresponding increase in the participants' looking at the numerical display. When there were 2 concurrent emergency events instead of 1, total viewing time did not increase, suggesting that participants did not need to change their viewing strategy when the emergency situation complexity increased. Also, during emergencies, participants directed nearly half of their fixations to the configural display during the first 2 seconds of an emergency, while only directing fewer than 5% of fixations to the numerical display during that same period. The average response time for an emergency event was around 2 seconds, which suggests that participants obtained relevant information from the configural display in this time period. We found that when a patient monitor contains both a configural display and a numerical display, participants look at the configural display. Furthermore, during time-sensitive situations, participants utilize the configural display to provide important information. We suggest this because the configural display integrates the relevant vital signs into one display. These findings provide justification for pursuing integrated vital sign displays to efficiently communicate patient conditions in complex environments. On the battlefield, swift decision-making is essential, as combat medics must minimize the time required to assess and act in critical situations.

Mindful Awareness Related to Working Memory Capacity and Response Inhibition

Objectives: This study investigated the associations among trait mindfulness, working memory capacity (WMC), and response inhibition. Mindfulness and WMC are thought to involve goal maintenance while resolving competing responses (inhibition), and studies have indeed found associations among mindfulness, WMC, and response inhibition. However, previous studies focused primarily on behavioral inhibition and many failed to differentiate components of mindfulness (awareness and acceptance). This study examined how self-reported mindfulness (awareness and acceptance) related to performance on tasks of WMC and multiple types of response inhibition (i.e., behavioral inhibition, interference control, and cognitive inhibition). Methods: Sixty-seven undergraduate students (75% female) received extra credit for participation. Measures included the Philadelphia Mindfulness Scale (measuring awareness and acceptance), Hayling Task (cognitive inhibition), go/nogo task (behavioral inhibition), Attention Network Test (interference control), n-back task (WMC), and Automated Reading Span Task (WMC). Results: Higher self-reported awareness was related to stronger performance on two measures of WMC (r =.29; r =.32) and multiple measures of response inhibition, including behavioral inhibition (r = -.25), interference control (r = -.25), and cognitive inhibition (r = -.28); response inhibition and WMC accounted for 22% and 16% of the variance in awareness respectively. No relations were found between self-reported acceptance and cognitive performance. Conclusions: Overall, this study found that the Mindfulness component of higher awareness (but not the component of acceptance) was related to stronger WMC and response inhibition. Because Mindfulness, WMC, and response inhibition are related in unique ways to healthy functioning and wellbeing; learning about how they interact increases scientific understanding, and suggests a direction for potential interventions to target these areas.

Individual Differences in Fatigued Performance

Cognitive fatigue is a prevalent issue across multiple military operational domains, resulting in degraded mission performance and costly mishaps. One approach to mitigating the effects of fatigue in operational environments is to develop technology, such as biomathematical, physiological, and cognitive models, that can help individuals assess and predict their fatigue and its impacts on performance. We can further enhance the accuracy of these models by incorporating individual difference metrics that allow for increased individualization. In the current study, we examine how individual differences in circadian typology, typical sleep duration, sleep duration need, and hardiness relate to fatigued performance during a 24-hr long mobility aircraft simulator session with mobility aircrews. Specifically, we examine individual difference relationships with performance on three cognitive tasks, the Psychomotor Vigilance Test, the N-back task, and the Change Signal Task, which measure processes crucial to operational performance: attention, working memory, and executive functioning.

Executive functions and divergent thinking in young adults: Evidence from individual differences and cognitive training studies

The interplay between executive functions and divergent thinking remains a debated question in creativity research. To address this issue, two studies were conducted from different perspectives. The first study explored which of the executive functioning components—namely working memory, inhibition, and shifting—predicted divergent thinking. A sample of 203 college students performed a battery of tasks assessing divergent thinking, executive functions, and related cognitive variables (fluid intelligence, verbal fluency, and processing speed). After statistically controlling for these variables, only working memory emerged as a significant predictor of creativity scores in the Alternative Uses Task, while inhibition and shifting did not. In the second study, a cognitive training approach was employed to further elucidate the potential efficacy of working memory training in fostering divergent thinking. The results found that the experimental group, which received a 15-day dual n-back task training, demonstrated greater improvements in the creativity score of the Alternative Uses Task compared to the control group, suggesting a transfer effect from working memory training to divergent thinking. This research underscores the plasticity of divergent thinking and highlights a plausible avenue for enhancing creativity through targeted cognitive training.

Is precrastination related to updating and inhibition aspects of executive function?

ABSTRACT Precrastination is the act of completing a task as soon as possible even at the expense of extra effort. Past research has suggested that individuals precrastinate due to a desire to reduce their cognitive load, also known as the cognitive load-reduction (CLEAR) hypothesis [VonderHaar, R. L., McBride, D. M., & Rosenbaum, D. A. (2019). Task order choices in cognitive and perceptual-motor tasks: The cognitive-load-reduction (CLEAR) hypothesis. Attention, Perception, & Psychophysics, 81(7), 2517–2525. https://doi.org/10.3758/s13414-019-01754-z]. This idea stems from the notion that it is taxing to hold intentions in working memory and completing a task as soon as possible releases cognitive resources for other tasks. Based on this hypothesis, we predicted that aspects of executive function may play a role in precrastination. We tested this prediction using a box-moving task developed in a previous study to measure precrastination. We also incorporated tasks measuring updating and inhibition aspects of executive function: the Stroop interference (both experiments) and Simon tasks (Experiment 2) to measure inhibition and the 2-Back memory task (Experiment 1) to measure updating. We found that the majority of participants precrastinated significantly throughout the box-moving task trials, consistent with results from past studies. However, no relation was found between the executive function tasks and rates of precrastination. These results may be due to the automaticity of precrastination when cognitive resources are limited.

Sub-bundle based analysis reveals the role of human optic radiation in visual working memory.

White matter (WM) functional activity has been reliably detected through functional magnetic resonance imaging (fMRI). Previous studies have primarily examined WM bundles as unified entities, thereby obscuring the functional heterogeneity inherent within these bundles. Here, for the first time, we investigate the function of sub-bundles of a prototypical visual WM tract-the optic radiation (OR). We use the 7T retinotopy dataset from the Human Connectome Project (HCP) to reconstruct OR and further subdivide the OR into sub-bundles based on the fiber's termination in the primary visual cortex (V1). The population receptive field (pRF) model is then applied to evaluate the retinotopic properties of these sub-bundles, and the consistency of the pRF properties of sub-bundles with those of V1 subfields is evaluated. Furthermore, we utilize the HCP working memory dataset to evaluate the activations of the foveal and peripheral OR sub-bundles, along with LGN and V1 subfields, during 0-back and 2-back tasks. We then evaluate differences in 2bk-0bk contrast between foveal and peripheral sub-bundles (or subfields), and further examine potential relationships between 2bk-0bk contrast and 2-back task d-prime. The results show that the pRF properties of OR sub-bundles exhibit standard retinotopic properties and are typically similar to the properties of V1 subfields. Notably, activations during the 2-back task consistently surpass those under the 0-back task across foveal and peripheral OR sub-bundles, as well as LGN and V1 subfields. The foveal V1 displays significantly higher 2bk-0bk contrast than peripheral V1. The 2-back task d-prime shows strong correlations with 2bk-0bk contrast for foveal and peripheral OR fibers. These findings demonstrate that the blood oxygen level-dependent (BOLD) signals of OR sub-bundles encode high-fidelity visual information, underscoring the feasibility of assessing WM functional activity at the sub-bundle level. Additionally, the study highlights the role of OR in the top-down processes of visual working memory beyond the bottom-up processes for visual information transmission. Conclusively, this study innovatively proposes a novel paradigm for analyzing WM fiber tracts at the individual sub-bundle level and expands understanding of OR function.

Single session and repeated anodal transcranial direct current stimulation over the right dorsolateral prefrontal cortex increases reflective thinking but not working memory updating performance

BackgroundAnodal transcranial direct current stimulation (tDCS) over the right dorsolateral prefrontal cortex (DLPFC) has shown to have effects on different domains of cognition yet there is a gap in the literature regarding effects on reflective thinking performance. ObjectiveThe current study investigated if single session and repeated anodal tDCS over the right DLPFC induces effects on judgment and decision-making performance and whether these are linked to working memory (updating) performance or cognitive inhibition. MethodsParticipants received anodal tDCS over the right DLPFC once (plus sham tDCS in a second session) or twice (24 h apart). In the third group participants received a single session of sham stimulation only. Cognitive characteristic measures were administered pre-stimulation (thinking disposition, impulsivity, cognitive ability). Experimental tasks included two versions of the Cognitive Reflection Test (numeric vs verbal-CRT), a set of incongruent base-rate vignettes, and two working memory tests (Sternberg task and n-back task). Forty-eight participants (mean age = 26.08 ± 0.54 years; 27 females) were recruited. ResultsSingle sessions of tDCS were associated with an increase in reflective thinking performance compared to the sham conditions, with stimulation improving scores on incongruent base rate tasks as well as marginally improving numeric CRT scores (compared to sham), but not thinking tasks without a numeric component (verbal-CRT). Repeated anodal stimulation only improved numeric CRT scores. tDCS did not increase working memory (updating) performance. These findings could not be explained by a practice effect or a priori differences in cognitive characteristics or impulsivity across the experimental groups. ConclusionThe current results demonstrate the involvement of the right DLPFC in reflective thinking performance which cannot be explained by working memory (updating) performance or general cognitive characteristics of participants.

Brain correlates of attentional load processing reflect degree of bilingual engagement: Evidence from EEG

The present study uses electroencephalography (EEG) with an N-back task (0-, 1-, and 2-back) to investigate if and how individual bilingual experiences modulate brain activity and cognitive processes. The N-back is an especially appropriate task given recent proposals situating bilingual effects on neurocognition within the broader attentional control system (Bialystok and Craik, 2022). Beyond its working memory component, the N-Back task builds in complexity incrementally, progressively taxing the attentional system. EEG, behavioral and language/social background data were collected from 60 bilinguals. Two cognitive loads were calculated: low (1-back minus 0-back) and high (2-back minus 0-back). Behavioral performance and brain recruitment were modeled as a function of individual differences in bilingual engagement. We predicted task performance as modulated by bilingual engagement would reflect cognitive demands of increased complexity: slower reaction times and lower accuracy, and increase in theta, decrease in alpha and modulated N2/P3 amplitudes. The data show no modulation of the expected behavioral effects by degree of bilingual engagement. However, individual differences analyses reveal significant correlations between non-societal language use in Social contexts and alpha in the low cognitive load condition and age of acquisition of the L2/2L1 with theta in the high cognitive load. These findings lend some initial support to Bialystok and Craik (2022), showing how certain adaptations at the brain level take place in order to deal with the cognitive demands associated with variations in bilingual language experience and increases in attentional load. Furthermore, the present data highlight how these effects can play out differentially depending on cognitive testing/modalities – that is, effects were found at the TFR level but not behaviorally or in the ERPs, showing how the choice of analysis can be deterministic when investigating bilingual effects.