Task Performance Research Articles

Chronic cannabis use alters the spontaneous and oscillatory gamma dynamics serving cognitive control.

Regular cannabis use is associated with cortex-wide changes in spontaneous and oscillatory activity, although the functional significance of such changes remains unclear. We hypothesized that regular cannabis use would suppress spontaneous gamma activity in regions serving cognitive control and scale with task performance. Participants (34 cannabis users, 33 nonusers) underwent an interview regarding their substance use history and completed the Eriksen flanker task during magnetoencephalography (MEG). MEG data were imaged in the time-frequency domain and virtual sensors were extracted from the peak voxels of the grand-averaged oscillatory interference maps to quantify spontaneous gamma activity during the pre-stimulus baseline period. We then assessed group-level differences in spontaneous and oscillatory gamma activity, and their relationship with task performance and cannabis use metrics. Both groups exhibited a significant behavioral flanker interference effect, with slower responses during incongruent relative to congruent trials. Mixed-model ANOVAs indicated significant gamma-frequency neural interference effects in the left frontal eye fields (FEF) and left temporoparietal junction (TPJ). Further, a group-by-condition interaction was detected in the left FEF, with nonusers exhibiting stronger gamma oscillations during incongruent relative to congruent trials and cannabis users showing no difference. In addition, spontaneous gamma activity was sharply suppressed in cannabis users relative to nonusers in the left FEF and TPJ. Finally, spontaneous gamma activity in the left FEF and TPJ was associated with task performance across all participants, and greater cannabis use was associated with weaker spontaneous gamma activity in the left TPJ of the cannabis users. Regular cannabis use was associated with weaker spontaneous gamma in the TPJ and FEF. Further, the degree of use may be proportionally related to the degree of suppression in spontaneous activity in the left TPJ.

The Impact of Employees’ Perceived Usefulness of AI on Creativity and Task Performance

The Impact of Employees’ Perceived Usefulness of AI on Creativity and Task Performance

Ambivalence in the Leader-Member Exchange and Task Performance: A Conservation of Resources Theory

Ambivalence in the Leader-Member Exchange and Task Performance: A Conservation of Resources Theory

When Follower Anxiety Expression Promotes Task Performance? A Self-Concordance Model Perspective

When Follower Anxiety Expression Promotes Task Performance? A Self-Concordance Model Perspective

Improving Human Sustainability at Work by Reducing Cognitive Load of Task Performance

Improving Human Sustainability at Work by Reducing Cognitive Load of Task Performance

A Latent Trait Approach to the Measurement of Physical Fitness

ABSTRACT A latent trait model for the measurement of physical fitness is proposed. It links the performance in competitions or the laboratory to a latent trait. In contrast to usual approaches that simply consider the sum of scores obtained from quite differently scaled tasks like time to run 100 m and jumping distance to obtain a measure of fitness, it distinguishes between the trait to be measured and the performance in the tradition of latent trait models. The latent trait model that is used is able to account for continuous observations, which distinguishes it from the classical latent trait models for binary or categorical data typically used in the measurement of mental abilities. Tools for the investigation of the contribution of single tasks and the link between task performances with respect to the latent trait are proposed and illustrated exemplarily by using decathlon data.

Improvement of Motor Task Performance: Effects of Verbal Encouragement and Music—Key Results from a Randomized Crossover Study with Electromyographic Data

External motivational stimuli have been shown to improve athletic performance. However, the neurophysiological mechanisms underlying this improvement remain poorly understood. This randomized crossover study investigated the effects of music and verbal encouragement on measures of muscle excitation and myoelectric manifestations of fatigue in the biceps brachii and brachioradialis muscles during an endurance task. Fifteen untrained (mean age 29.57 ± 2.77 years) and 13 trained individuals (mean age 32.92 ± 2.90 years) were included. The endurance task, performed to exhaustion, consisted of keeping the dominant arm flexed to 90 degrees while holding a dumbbell loaded to 80% of 1RM with a supine grip in three randomized conditions: standard, with self-selected music, and with verbal encouragement. The untrained subjects showed an increase in task duration of 15.26% (p < 0.003) with music and 15.85% (p < 0.002) with verbal encouragement compared to the condition without external stimuli. There were no significant differences in the myoelectric manifestations of fatigue between the different conditions. Regarding the muscle excitation metrics, although the mean amplitude, peak value, and area under the curve remained unchanged across conditions, a significant reduction in the trend coefficient, indicating motor unit recruitment over time, was observed with both music (biceps brachii: −10.39%, p < 0.001; brachioradialis: −9.40%, p < 0.001) and verbal encouragement (biceps brachii: −7.61%, p < 0.001; brachioradialis: −6.51%, p < 0.001) compared to the standard condition. For the trained participants, no significant differences were observed between conditions in terms of task duration and outcome measures related to muscle excitation and myoelectric manifestations of fatigue, suggesting the possible presence of a ceiling effect on motivation. These results highlight the important role of external motivational stimuli, such as music and verbal encouragement, in improving task performance in untrained subjects, probably through more effective and efficient recruitment of motor units.

Circadian-informed lighting improves vigilance, sleep, and subjective sleepiness during simulated night shift work.

Shiftwork is associated with cognitive impairment and reduced sleep time and quality, largely due to circadian misalignment. This study tested if circadian-informed lighting could improve cognitive performance and sleep during simulated night shifts versus dim control lighting. Nineteen healthy participants (Mean±SD 29±10 years, 12 males, 7 females) were recruited to a laboratory study consisting of two counterbalanced 8-day lighting conditions (order randomized) 1-month apart: 1) control lighting condition- dim, blue-depleted and 2) circadian-informed lighting condition- blue-enriched and blue-depleted where appropriate. Participants underwent an adaptation night (22:00h - 07:00h), then four nights of simulated nightwork (cognitive testing battery of nine tasks, 00:00h - 08:00h) and sleep during the day (10:00h - 19:00h). Psychomotor vigilance task (PVT) lapses, Karolinska Sleepiness Scale (KSS) scores, and polysomnography-derived sleep outcomes were compared between conditions and across days using mixed models. Significant condition-by-day-by-time of task interaction effects were found for PVT lapses, median reaction time, and reaction speed, with ~50% fewer lapses by the end of simulated shiftwork with circadian-informed lighting versus control (mean±SD 7.4±5.0 vs. 15.6±6.1). KSS was lower around the nightshift midpoints on days 6 and 7 with circadian versus control lighting. Participants slept 52 minutes longer [95% CIs: 27.5, 76.5 mins] by Day 7 with circadian-informed versus control lighting, p<0.001. Effects were inconsistent on other performance tasks. Circadian-informed lighting improved sleep, sleepiness, and vigilance compared to control lighting. These findings support the potential for lighting interventions to improve sleep and vigilance in night shift workers chronically exposed to dim lighting.

Impairment of synaptic plasticity in the primary somatosensory cortex in a model of diabetic mice

Type 1 and type 2 diabetic patients experience alterations in the Central Nervous System, leading to cognitive deficits. Cognitive deficits have been also observed in animal models of diabetes such as impaired sensory perception, as well as deficits in working and spatial memory functions. It has been suggested that a reduction of insulin-like growth factor-I (IGF-I) and/or insulin levels may induce these neurological disorders. We have studied synaptic plasticity in the primary somatosensory cortex of young streptozotocin (STZ)-diabetic mice. We focused on the influence of reduced IGF-I brain levels on cortical synaptic plasticity. Unit recordings were conducted in layer 2/3 neurons of the primary somatosensory (S1) cortex in both control and STZ-diabetic mice under isoflurane anesthesia. Synaptic plasticity was induced by repetitive whisker stimulation. Results showed that repetitive stimulation of whiskers (8 Hz induction train) elicited a long-term potentiation (LTP) in layer 2/3 neurons of the S1 cortex of control mice. In contrast, the same induction train elicited a long-term depression (LTD) in STZ-diabetic mice that was dependent on NMDA and metabotropic glutamatergic receptors. The reduction of IGF-I brain levels in diabetes could be responsible of synaptic plasticity impairment, as evidenced by improved response facilitation in STZ-diabetic mice following the application of IGF-I. This hypothesis was further supported by immunochemical techniques, which revealed a reduction in IGF-I receptors in the layer 2/3 of the S1 cortex in STZ-diabetic animals. The observed synaptic plasticity impairments in STZ-diabetic animals were accompanied by decreased performance in a whisker discrimination task, along with reductions in IGF-I, GluR1, and NMDA receptors observed in immunochemical studies. In conclusion, impaired synaptic plasticity in the S1 cortex may stem from reduced IGF-I signaling, leading to decreased intracellular signal pathways and thus, glutamatergic receptor numbers in the cellular membrane.

Does it take two to tango? Combined effects of relational job crafting and job design on energy and performance

SummaryDespite an extensive body of research on job crafting, our understanding of how bottom‐up job crafting behaviors interact with top‐down job design in influencing employee effectiveness remains limited. Drawing on conservation of resources theory, we developed and tested a theoretical framework to examine the implications of daily promotion‐ versus prevention‐oriented relational job crafting on employees' energy and subsequent task performance, in the context of relational job design (i.e., task interdependence). To test our theorizing, we conducted two experience‐sampling studies over 10 workdays with full‐time employees across various organizations (Study 1: Nday‐level = 845, Nperson‐level = 126; Study 2: Nday‐level = 793, Nperson‐level = 108). Multilevel path modeling indicated promotion‐oriented relational job crafting was positively associated with subsequent task performance by increasing energy levels (Study 2), particularly when task interdependence was low (Study 1). In contrast, prevention‐oriented relational job crafting was energy depleting in low‐task‐interdependent contexts (Study 2) but increased employees' energy in high‐task‐interdependent contexts (Study 1). Our findings suggest different forms of day‐to‐day relational job crafting behaviors are relevant for employees' energy and performance, but their effectiveness may depend on the relational job‐design context.

BMCS-Net: A Bi-directional multi-scale cascaded segmentation network based on transformer-guided feature Aggregation for medical images

convolutional neural networks (CNNs) show great potential in medical image segmentation tasks, and can provide reliable basis for disease diagnosis and clinical research. However, CNNs exhibit general limitations on modeling explicit long-range relation, and existing cures, resorting to building deep encoders along with aggressive downsampling operations, leads to loss of localized details. Transformer has naturally excellent ability to model the global features and long-range correlations of the input information, which is strongly complementary to the inductive bias of CNNs. In this paper, a novel Bi-directional Multi-scale Cascaded Segmentation Network, BMCS-Net, is proposed to improve the performance of medical segmentation tasks by aggregating these features obtained from Transformers and CNNs branches. Specifically, a novel feature integration technique, termed as Two-stream Cascaded Feature Aggregation (TCFA) module, is designed to fuse features in two-stream branches, and solve the problem of gradual dilution of global information in the network. Besides, a Multi-Scale Expansion-Aware (MSEA) module based on the convolution of feature perception and expansion is introduced to capture context information, and further compensate for the loss of details. Extensive experiments demonstrated that BMCS-Net has an excellent performance on both skin and Polyp segmentation datasets.

EXPRESS: The Role of Articulatory Rehearsal in Short-Term False Memories during Aging.

Recent studies have shown that articulatory rehearsal prevents false memories in working memory tasks in young adults. During aging, a substantial increase in false memories has been documented in numerous studies. The aim of the present study was to investigate the role of rehearsal in the increase of false memories with age. In two experiments, we manipulated the opportunity to use rehearsal in a Brown-Peterson task in which younger (n = 80) and older (n = 70) adults maintained semantically related word lists and reported their maintenance strategies. Both experiments showed that reducing the opportunity to use rehearsal increased false memories and decreased correct recall in both groups. Furthermore, older adults made more false memories and less correct recall than younger adults, and these effects were partially mediated by the number of times participants reported using rehearsal (Exp. 2). These findings suggest that age-related differences in rehearsal use explain differences in working memory task performance.

EXPRESS: The Impact of Subtle Contextual Information on Remembering to Complete Academic Goals.

Remembering to complete goals-termed prospective memory (PM)-is critical for success in everyday life, yet minimal empirical work has been dedicated to examining prospective memory within an educational setting. The main goal of this study was to investigate students' ability to complete numerous future-oriented academic intentions (PM tasks) while simultaneously paying attention to a lecture and to see if working memory capacity (WM) and adding subtle contextual information would support the students' likelihood of completing their PM tasks. Participants took part in a 2-hour session of college course-like activities. Throughout the session, there was occasionally the opportunity to complete one of several naturalistic PM tasks. The following findings are based on the results of our Bayesian models. Providing subtle contextual clues about when PM tasks could be completed was found to likely increase performance. The number of PM intentions to be remembered (i.e., load) produced no discernable effect on ongoing task performance or PM performance. Furthermore, individual differences in WM capacity were likely to be predictive of a near-zero change in PM performance. The current findings hold meaningful implications for educators, wherein providing context, even at a subtle level, can enhance students' ability to remember to complete tasks, without altering their ability to focus on the tasks at hand. Moreover, it appears that asking students to remember to complete multiple, prospective in-class tasks is not likely to hinder task completion or their ability to focus on other ongoing tasks.

Spiking attractor model of motor cortex explains modulation of neural and behavioral variability by prior target information

When preparing a movement, we often rely on partial or incomplete information, which can decrement task performance. In behaving monkeys we show that the degree of cued target information is reflected in both, neural variability in motor cortex and behavioral reaction times. We study the underlying mechanisms in a spiking motor-cortical attractor model. By introducing a biologically realistic network topology where excitatory neuron clusters are locally balanced with inhibitory neuron clusters we robustly achieve metastable network activity across a wide range of network parameters. In application to the monkey task, the model performs target-specific action selection and accurately reproduces the task-epoch dependent reduction of trial-to-trial variability in vivo where the degree of reduction directly reflects the amount of processed target information, while spiking irregularity remained constant throughout the task. In the context of incomplete cue information, the increased target selection time of the model can explain increased behavioral reaction times. We conclude that context-dependent neural and behavioral variability is a signum of attractor computation in the motor cortex.

Selectively maintaining an object's feature in visual working memory: A comparison between highly discriminable and fine-grained features.

Selectively maintaining information is an essential function of visual working memory (VWM). Recent VWM studies have mainly focused on selective maintenance of objects, leaving the mechanisms of selectively maintaining an object's feature in VWM unknown. Based on the interactive model of perception and VWM, we hypothesized that there are distinct selective maintenance mechanisms for objects containing fine-grained features versus objects containing highly discriminable features. To test this hypothesis, we first required participants to memorize a dual-feature object (colored simple shapes vs. colored polygons), and informed them about the target feature via a retro-cue. Then a visual search task was added to examine the fate of the irrelevant feature. The selective maintenance of an object's feature predicted that the irrelevant feature should be removed from the active state of VWM and should not capture attention when presented as a distractor in the visual search task. We found that irrelevant simple shapes impaired performance in the visual search task (Experiment 1). However, irrelevant polygons did not affect visual search performance (Experiment 2), and this could not be explained by decay of polygons (Experiment 3) or by polygons not capturing attention (Experiment 4). These findings suggest that VWM adopts dissociable mechanisms to selectively maintain an object's feature, depending on the feature's perceptual characteristics.

Enhancing E-learning in higher education: Lessons learned from the pandemic

This study delves into the intricate realm of evaluating and refining e-learning practices, drawing upon insights from esteemed higher education professionals. Through a qualitative lens rooted in phenomenology, the research engages in semi-structured interviews with 30 faculty members from seven public universities in Tehran, ensuring theoretical saturation. Employing inductive content analysis, the data examination unveils three core categories of challenges: educational assessment, research evaluation, and university services. Emphasizing the significance of internal task performance, adaptability to dynamic environments, and external institutional promotion, the study advocates for the development of a comprehensive evaluation model and tools to uphold program quality, efficiency, and effectiveness. Against the backdrop of the COVID-19 pandemic, the research highlights the pressing need for Iranian higher education to bolster productivity through strategic resource allocation across education, research, services, and human capital development domains. Such efforts are pivotal in shaping a more prosperous future and bolstering societal scientific and cultural standing.

Speech-Gesture Matching and Schizotypal Traits: A Network Approach.

Impaired speech-gesture matching has repeatedly been shown in patients with schizophrenia spectrum disorders. Here, we tested the hypothesis that schizotypal traits in the general population are related to reduced speech-gesture matching performance and reduced self-reports about gesture perception. We further explored the relationships between facets of schizotypy and gesture processing in a network model. Participants (1094 mainly healthy adults) were presented with concrete or abstract sentences accompanied with videos showing related or unrelated gestures. For each video, participants evaluated the alignment between speech and gesture. They also completed self-rating scales about the perception and production of gestures (Brief Assessment of Gesture scale) and schizotypal traits (Schizotypal Personality Questionnaire-Brief 22-item version). We analyzed bivariate associations and estimated a non-regularized partial Spearman correlation network. We characterized the network by analyzing bridge centrality and controllability metrics of nodes. We found a negative relationship between both concrete and abstract gesture-speech matching performance and overall schizotypy. In the network, disorganization had the highest average controllability and it was negatively related to abstract speech-gesture matching. Bridge centralities indicated that self-reported production of gestures to enhance communication in social interactions connects self-reported gesture perception, schizotypal traits, and gesture processing task performance. The association between impaired abstract speech-gesture matching and disorganization supports a continuum between schizophrenia and schizotypy. Using gestures to facilitate communication connects subjective and objective aspects of gesture processing and schizotypal traits. Future interventional studies in patients should test the potential causal pathways implied by this network model.

Using Task-fMRI to Explore the Relationship Between Lifetime Cannabis Use and Cognitive Control in Individuals with First Episode Schizophrenia

Abstract While continued cannabis use and misuse in individuals with schizophrenia is associated with a variety of negative outcomes, individuals with a history of use tend to show higher cognitive performance compared to non-users. While this is replicated in the literature, few studies have used task-based functional magnetic resonance imaging (fMRI) to evaluate whether the brain networks underpinning these cognitive features are similarly impacted. Forty-eight first episode individuals with schizophrenia (FES) with a history of cannabis use (FES+CAN), 28 FES individuals with no history of cannabis use (FES-CAN), and 59 controls (CON) performed the AX-Continuous Performance Task during fMRI. FES+CAN showed higher cognitive control performance (d’-context) compared to FES-CAN (p&amp;lt;.05, ηp2=.053), and both FES+CAN (p&amp;lt;.05, ηp2=.049) and FES-CAN (p&amp;lt;.001, ηp2=.216) showed lower performance compared to CON. FES+CAN (p&amp;lt;.05, ηp2=.055) and CON (p&amp;lt;.05, ηp2=.058) showed higher dorsolateral prefrontal cortex (DLPFC) activation during the task compared to FES-CAN, while FES+CAN and CON were not significantly different. Within the FES+CAN group, younger age of initiation of cannabis use was associated with lower IQ and lower global functioning. More frequent use was also associated with higher reality distortion symptoms at the time of the scan. These data are consistent with previous literature suggesting that individuals with schizophrenia and a history of cannabis use have higher cognitive control performance. For the first time, we also reveal that FES+CAN have higher DLPFC brain activity during cognitive control compared to FES-CAN. Several possible explanations for these findings are discussed.

Prefrontal oscillatory slowing in early-course schizophrenia is associated with worse cognitive performance and negative symptoms: a TMS-EEG study

Abnormalities in dorsolateral prefrontal cortex (DLPFC) oscillations are neurophysiological signatures of schizophrenia thought to underlie its cognitive deficits. Transcranial magnetic stimulation with electroencephalography (TMS-EEG) provides a measure of cortical oscillations unaffected by sensory relay functionality and/or patients' level of engagement, which are important confounding factors in schizophrenia. Previous TMS-EEG work showed reduced fast, gamma-range oscillations and a slowing of the main DLPFC oscillatory frequency, or natural frequency, in chronic schizophrenia. However, it is unclear whether this DLPFC natural frequency slowing is present in early-course schizophrenia (EC-SCZ) and is associated with symptom severity and cognitive dysfunction. We applied TMS-EEG to the left DLPFC in 30 EC-SCZ and 28 healthy control (HC) subjects. Goal-directed working memory performance was assessed using the "AX" Continuous Performance Task (AX-CPT). The EEG frequency with the highest cumulative power at the stimulation site, or natural frequency, was extracted. We also calculated the local Relative Spectral Power (RSP) as the average power in each frequency band divided by the broadband power. Compared to HC, EC-SCZ had reduced DLPFC natural frequency (p=0.0000002, Cohen's d=-2.32) and higher DLPFC beta-range RSP (p=0.0003, Cohen's d=0.77). In EC-SCZ, the DLPFC natural frequency was inversely associated with negative symptoms. Across all participants, the beta-band RSP negatively correlated with the AX-CPT performance. A DLPFC oscillatory slowing is an early pathophysiological biomarker of schizophrenia that is associated with its symptom severity and cognitive impairments. Future work should assess whether non-invasive neurostimulation can ameliorate prefrontal oscillatory deficits and related clinical functions in EC-SCZ.

Does innovative behaviour intervene between budgetary participation and performance in the public sector?

Purpose For a public servant (PS) to be innovative, he or she needs to gather and process enough vital information from budget setting processes. However, research addressing how budgetary participation (BP) can trigger innovative behaviour (IB) in PSs and eventually foster task performance (TP) is rare, which is why the authors conduct this research. The purpose of this study is to understand how BP shapes TP through the IB of PSs. Design/methodology/approach The authors develop and test a mediation model with 860 responses from public sector workers across 25 government agencies using the PLS-SEM technique of Smart PLS 4. Possible control factors were addressed for both the mediator and target-independent construct. In particular, the authors use sex, age and tenure as control factors for IB. Also, the authors use job satisfaction, job engagement and perceived fairness in the budgetary system as control factors for TP. Findings The authors find a favourable and significant relationship between BP and TP; BP and IB; and IB and TP. The authors also find that IB partially mediates the relationship between BP and TP, such that BP fosters TP through the innovativeness of PSs. This finding suggests that PSs who participate in budget preparation are able to innovate, which, in turn enable them to perform tasks effectively. Research limitations/implications The authors call on forthcoming researchers to test the mediation model in other public sector settings worldwide. They may also consider other variables that can possibly mediate the positive impacts of BP on TP. Practical implications Lessons are discussed for governments, human resources directors and managers, management accountants, budget officers, procurement officers and other public sector workers and consultants. Originality/value The authors show how BP fosters TP through the innovativeness of PSs, since there is much more to know in this regard. The authors also help to resolve the paradox of inconsistency in the BP–TP literature by using IB as a mediator.