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Increasing evidence shows that virtual reality (VR) training is highly effective in cognitive and motor rehabilitation. Another modern form of training is cognitive–motor dual-task training (CMDT), which has been demonstrated to rapidly improve physical and cognitive functions in real environments. This study aims to test whether a VR-based CMDT protocol can be used for motor and cognitive skill enhancement in young, healthy subjects. For this aim, 24 university students participated in a randomized control trial. The experimental group participated in a 5-week virtual reality reaction training (VRRT), performing 30 min sessions once a week. The control group did not receive any training but was tested twice with the same measures and temporal distance as the experimental group. Before and after the intervention, motor, cognitive, and electrophysiological measures were assessed. The results showed that following VRRT, the response time for both physical and cognitive tests was improved by about 14% and 12%, respectively, while the control group did not show significant changes. Moreover, electrophysiological data revealed a significant increase in anticipatory motor readiness in premotor brain areas in the experimental group only; however, cognitive top–down control tended to be increased in prefrontal areas after VRRT. This training protocol in a VR modality seems to be as effective as other CMDT methodologies carried out in a real modality. Still, it has the advantages of being more flexible and more user-friendly compared to standard training. The VRRT's efficacy on physical and cognitive functions indicates that virtual reality applications can be used by the young population, not only for entertainment purposes but also in the form of cognitive–motor training. [ABSTRACT FROM AUTHOR]

Attention can be directed to the global or local level of a visual stimulus (i.e., Navon figure). Previous studies yielded reliable trial-to-trial level switch costs (i.e., worse performance when responding to the other level than on a previous trial), even though level cueing effects indicated anticipatory deployment of attention to the upcoming target level. To investigate the interplay of attentional preparation and persistence, we applied a probe trial method assumed to ensure a high degree of preparation for the upcoming target level and minimizing stimulus-specific proactive interference. Mirroring previous findings obtained in the domain of spatial attention, we found evidence for anticipatory attentional focusing on global/local target levels but not for persistence of the attentional set adopted on the previous trial. In a second experiment, we prevented preparation for upcoming attentional demands (in both global-local and spatial attention tasks). This resulted in the modulation of performance (in critical probe trials) by the attentional demands of the predecessor trial. Together, our findings demonstrate sensitivity of the probe trial method for attentional persistence and raise the possibility that such persistence can be completely eliminated by sufficiently strong preparation for the attentional demands of the following trial.

Anticipatory event-related potentials (ERPs) precede upcoming events such as stimuli or actions. These ERPs are usually obtained in cued sensory–motor tasks employing a warning stimulus that precedes a probe stimulus as in the contingent negative variation (CNV) paradigms. The CNV wave has been widely studied, from clinical to brain–computer interface (BCI) applications, and has been shown to emerge in medial frontoparietal areas, localized in the cingulate and supplementary motor areas. Several dated studies also suggest the existence of a prefrontal CNV, although this component was not confirmed by later studies due to the contamination of ocular artifacts. Another lesser-known anticipatory ERP is the prefrontal negativity (pN) that precedes the uncued probe stimuli in discriminative response tasks and has been localized in the inferior frontal gyrus. This study aimed to characterize the pN by comparing it with the CNV in cued and uncued tasks and test if the pN could be associated with event preparation, temporal preparation, or both. To achieve these aims, high-density electroencephalographic recording and advanced ERP analysis controlling for ocular activity were obtained in 25 volunteers who performed 4 different visuomotor tasks. Our results showed that the pN amplitude was largest in the condition requiring both time and event preparation, medium in the condition requiring event preparation only, and smallest in the condition requiring temporal preparation only. We concluded that the prefrontal CNV could be associated with the pN, and this activity emerges in complex tasks requiring the anticipation of both the category and timing of the upcoming stimulus. The proposed method can be useful in BCI studies investigating the endogenous neural signatures triggered by different sensorimotor paradigms. [ABSTRACT FROM AUTHOR]

A key element of human flexible behavior concerns the ability to continuously predict and prepare for sudden changes in tasks or actions. Here, we tested whether people can dynamically modulate task preparation processes and decision-making strategies when the identity of a to-be-performed task becomes uncertain. To this end, we developed a new paradigm where participants need to prepare for one of nine tasks on each trial. Crucially, in some blocks, the task being prepared could suddenly shift to a different task after a longer cue-target interval, by changing either the stimulus category or categorization rule that defined the initial task. We found that participants were able to dynamically modulate task preparation in the face of this task uncertainty. A second experiment shows that these changes in behavior were not simply a function of decreasing task expectancy, but rather of increasing switch expectancy. Finally, in the third and fourth experiment, we demonstrate that these dynamic modulations can be applied in a compositional manner, depending on whether either only the stimulus category or categorization rule would be expected to change. [ABSTRACT FROM AUTHOR]

Abstract Daily life is filled with sequences of multiple tasks, each with their own relevant perceptual input. Working memory needs to dissociate representations that drive attention towards currently relevant information from prospective representations that are needed for future tasks, but that until then should be prevented from guiding attention. Yet, little is known about how the brain initiates and controls such sequential prioritization of selection. In the current study we recorded EEG while subjects remembered a color as the target template for one of two sequential search tasks, thus making it either currently relevant (when it was the target for the first search) or prospectively relevant (when it was the target for the second search) prior to the task sequence. Using time-frequency specific linear classifiers, we were able to predict the priority status (current versus prospective) of the memory representation from multivariate patterns of delta (2–4 Hz) and non-lateralized alpha power (8–14 Hz) during both delay periods. The delta band was only transiently involved when initializing the priority status at the start of the first delay, or when switching priority during the second delay, which we interpret as reflecting the momentary top-down control over prioritization. In contrast, alpha power decoding was based on a more stable pattern of activity that generalized across time both within and between delay periods, which we interpret as reflecting a difference in the prioritized memory representations themselves. Taken together, we reveal the involvement of a complex, distributed and dynamic spatiotemporal landscape of frequency-specific oscillatory activity in controlling prioritization of information within working memory. Highlights • MVPA of EEG oscillatory signals dissociates current from future perceptual tasks • Current versus future status can be decoded during the delay prior to the tasks • Status decoding is reflected specifically in oscillatory delta and alpha band activity • Spatial pattern of activity underlying status decoding is complex and distributed • MVPA more sensitive than univariate measures to study higher order brain states [ABSTRACT FROM AUTHOR]

Abstract Preparing for a mentally demanding task calls upon cognitive and motivational resources. The underlying neural implementation of these mechanisms is receiving growing attention because of its implications for professional, social, and medical contexts. While several fMRI studies converge in assigning a crucial role to a cortico-subcortical network including Anterior Cigulate Cortex (ACC) and striatum, the involvement of Dorsolateral Prefrontal Cortex (DLPFC) during mental effort anticipation has yet to be replicated. This study was designed to target DLPFC contribution to anticipation of a difficult task using functional Near Infrared Spectroscopy (fNIRS), as a more cost-effective tool measuring cortical hemodynamics. We adapted a validated mental effort task, where participants performed easy and difficult mental calculation, and measured DLPFC activity during the anticipation phase. As hypothesized, DLPFC activity increased during anticipation of a hard task as compared to an easy task. Besides replicating previous fMRI work, these results establish fNIRS as an effective tool to investigate cortical contributions to anticipation of effortful behavior. This is especially useful if one requires testing large samples (e.g., to target individual differences), populations with contraindication for functional MRI (e.g., infants or patients with metal implants), or subjects in more naturalistic environments (e.g., work or sport). Highlights • Anticipating a mentally effortful task recruits DLPFC, measured by fMRI. • fNIRS is a cost-effective method to measure cortical activity (oxyhemoglobin). • This study validates the use of fNIRS to measure difficulty anticipation in DLPFC. • Anticipating a hard task is associated with increased oxyhemoglobin in DLPFC. • fNIRS can be used in studies investigating the role of DLPFC in mental effort. [ABSTRACT FROM AUTHOR]

Abstract Previous research has shown that there are significant task-switching costs even when participants have time to prepare for task switching after cueing. We investigated individual differences in task switching by monitoring errors and response times of individual participants. In Experiment 1A, 58 participants were encouraged to finish the session early by completing 200 consecutive trials without making an error. In case of a mistake, they had to repeat their effort until the experimental session expired. Using this demanding procedure, 16 participants managed to complete early. Among these 16 we identified 9 best performers who showed no significant switch costs. We conducted follow-up Experiment 1B on these best performers by systematically varying cue-stimulus intervals and inter-trial intervals. The results confirmed that these participants had no significant RT and ER switch costs when they had time to prepare the task between cue and target onset. However, significant switch costs emerged when cue and target stimulus were presented simultaneously. In Experiment 1C, using three classical task-switching paradigms, we compared the best performers with 9 controls who had made frequent errors in Experiment 1A. Although the best performers responded faster and made fewer errors, they only showed reduced switch costs in a pre-cued paradigm that had been extensively practiced. In two other paradigms with simultaneous presentation of cue and target stimulus, best performers had switch costs and showed considerable individual differences similar to the controls. We conclude that there are considerable individual differences in task switching and that smaller individual switch costs are mainly related to efficient task preparation. We speculate that efficient task preparation may be linked to better executive control and general intelligence. Highlights • Participants vary considerably in their task switching performance. • There are participants who consistently show no switch costs in a cued paradigm. • Elimination of switch costs is due to efficient preparation in cue-stimulus intervals. • Efficient preparation may relate to better executive control and general intelligence. [ABSTRACT FROM AUTHOR]

The aim of the current study was to investigate the effects of postural control demands on cognitive control processes in concurrent auditory-manual task switching. To this end, two experiments were conducted using an auditory cued task-switching paradigm with different postural control demands (sitting vs. standing). This design allowed us to explore the effect of postural control on switch costs, mixing costs, and the between-task congruency effect. In addition, we varied the cue-based task preparation in Experiment 1 to examine whether preparation processes are independent of additional postural control demands or if the motor control processes required by the postural control demands interfere with task-specific cognitive preparation processes. The results show that we replicated the standard effects in task switching, such as switch costs, mixing costs, and congruency effects in both experiments as well as a preparation-based reduction of these costs in Experiment 1. Importantly, we demonstrated a selective effect of postural control demands in task switching in terms of an increased congruency effect when standing as compared to sitting. This finding suggests that particularly in situations that require keeping two tasks active in parallel, the postural control demands have an influence on the degree to which cognitive control enforces a more serial (shielded) mode or a somewhat less selective attention mode that allows for more parallel processing of concurrently held active task rules.

We investigated pupil dilation in 96 subjects during task preparation and during a post-trial interval in a visual search task and an auditory working memory task. Completely informative difficulty cues (easy, medium, or hard) were presented right before task preparation to examine whether pupil dilation indicated advance mobilisation of attentional resources; functional magnetic resonance imaging (fMRI) studies have argued for the existence of such task preparation, and the literature shows that pupil dilation tracks attentional effort during task performance. We found, however, little evidence for such task preparation. In the working memory task, pupil size was identical across cues, and although pupil dilation in the visual search task tracked the cue, pupil dilation predicted subsequent performance in neither task. Pupil dilation patterns in the post-trial interval were more consistent with an effect of emotional reactivity. Our findings suggest that the mobilisation of attentional resources in the service of the task does not occur during the preparatory interval, but is delayed until the task itself is initiated. [ABSTRACT FROM AUTHOR]

This study investigated cerebral blood flow modulations during task preparation in a precued saccade paradigm. Bilateral blood flow velocities in the middle cerebral arteries were recorded in 48 subjects using functional transcranial Doppler sonography. Video-based eye-tracking was applied for ocular recording. Antisaccade and prosaccade trials were presented in both block-wise and interleaved order. A right dominant flow response arose during task preparation. While the response was stronger during antisaccade than prosaccade trials, the degree of lateralisation did not differ between the two trial types. Direction error rates were higher and latencies were longer for antisaccades than prosaccades. There were no differences between block-wise and interleaved trials in blood flow or performance. The stronger blood flow increases during antisaccade than prosaccade preparation reflects the complexity of the upcoming task demands as well as proactive inhibition. The right hemispheric lateralisation may be attributed to preparatory attention independent of demands on inhibitory control. [ABSTRACT FROM AUTHOR]

When participants predict the upcoming stimulus in a randomized choice reaction task, a match between prediction and stimulus increases processing speed at a level similar to that observed in cueing studies with highly valid cues. This might be taken to suggest that people cannot help but fully use their self-generated, verbalized predictions for preparing task processing. Thus, we tested how flexibly participants can control formation and implementation of predictions. In Experiment 1, we varied validity and response-relevance of predictions. We observed that prediction effects on RT can be boosted by increasing validity, but prevail under adverse circumstances. This was not the case in a control group who read rather than predicted the feature words, suggesting that the effect was specific to predictions as such. Experiment 2 provided further evidence for limited control of participants over implementing and forming predictions. Participants were provided with practice on stimuli occurring with varying frequency, but neither learned to strategically choose predictions to maximize the number of match trials, nor did they reduce the amount of prediction-based preparation when predicting an infrequent stimulus. As sequential aftereffects of prediction match did not vary with validity, they were identified as an independent effect of verbalizing a response-relevant stimulus feature. The results are consistent with the view that the predicted stimulus feature is represented in the focus of attention in working memory and that the amount of implementation can be subject to weighting. [ABSTRACT FROM AUTHOR]

Visual selective attention is known to be guided by stimulus-based (bottom-up) and goal-oriented (top-down) control mechanisms. Recent work has pointed out that selection history (i.e., the bias to prioritize items that have been previously attended) can result in a learning experience that also has a substantial impact on subsequent attention guidance. The present study examined to what extent goal-oriented top-down control mechanisms interact with an observer's individual selection history in guiding attention. Selection history was manipulated in a categorization task in a between-subjects design, where participants learned that either color or shape was the response-relevant dimension. The impact of this experience was assessed in a compound visual search task with an additional color distractor. Top-down preparation for each search trial was enabled by a pretrial task cue (Experiment 1) or a fixed, predictable trial sequence (Experiment 2). Reaction times and ERPs served as indicators of attention deployment. Results showed that attention was captured by the color distractor when participants had learned that color predicted the correct response in the categorization learning task, suggesting that a bias for predictive stimulus features had developed. The possibility to prepare for the search task reduced the bias, but could not entirely overrule this selection history effect. In Experiment 3, both tasks were performed in separate sessions, and the bias still persisted. These results indicate that selection history considerably shapes selective attention and continues to do so persistently even when the task allowed for high top-down control. [ABSTRACT FROM AUTHOR]

When participants rapidly switch between tasks that share the same stimuli and responses, task confusions (i.e., the accidental application of the wrong task) can occur. The present study investigated whether these task confusions result from failures of endogenous control (i.e., from ineffective task preparation) or from failures of exogenous control (i.e., from stimulus-induced task conflicts). The frequency of task confusions was estimated by considering the relative proportion of distractor errors, that is, errors that result when participants erroneously respond to the distractor associated with the alternative task. In Experiment 1, the efficiency of exogenous control was manipulated by varying the temporal order of target and distractor presentation. In Experiment 2, the efficiency of endogenous control was manipulated by varying the time available for preparing the task in advance. It turned out that only the efficiency of exogenous control but not the efficiency of endogenous control influenced the proportion of distractor errors. Accordingly, task confusions are more related to failures in exogenous control.

The present study focused on the role of task preparation in age-related task-switching deficits. In Experiment 1, we assessed the preparatory reduction of alternation costs (i.e., alternating-task conditions vs. single-task conditions) in twenty-two older adults (65–78 years) and 22 young adults (20–28 years) by varying the response-stimulus interval (RSI) in a task-switching paradigm with a predictable task sequence and univalent stimuli. In Experiment 2, in which new groups of 22 older adults (65–78 years) and 22 young adults (18–24 years) took part, we replicated Experiment 1 with bivalent stimuli, which were associated with both tasks and thus increased task-set competition. Whereas in Experiment 1, in which we used univalent stimuli, there were no age-related differences in the preparatory reduction of alternation costs, the data showed impaired task preparation in old age with bivalent stimuli in Experiment 2. These data support the notion that task-preparation deficits in old age occur particularly in situations of increased task-set competition. [ABSTRACT FROM AUTHOR]

Recent neuroimaging studies have shown that working memory (WM) task difficulty can be decoded from patterns of brain activation in the WM network during preparation to perform those tasks. The inter-regional connectivity among the WM regions during task preparation has not yet been investigated. We examined this question using the graph modeling methods IMaGES and LOFS, applied to the previously published fMRI data of Manelis and Reder (2013). In that study, subjects performed 1-, 2-, and 3-back tasks. Each block of n-back was preceded by a preparation period and followed by a rest period. The analyses of task-related brain activity identified a network of 18 regions that increased in activation from 1- to 3-back (Increase network) and a network of 17 regions that decreased in activation from 1- to 3-back (Decrease network). The graph analyses revealed two types of connectivity sub-networks within the Increase and Decrease networks: default and preparation-related. The default connectivity was present not only during task performance, but also during task preparation and during rest. We propose that this sub-network may serve as a core system that allows one to quickly activate cognitive, perceptual and motor systems in response to the relevant stimuli. The preparation-related connectivity was present during task preparation and task performance, but not at rest, and depended on the n-back condition. The role of this sub-network may be to pre-activate a connectivity road map in order to establish a top-down and bottom-up regulation of attention prior to performance on WM tasks.

When participants rapidly switch between tasks that share the same stimuli and responses, task confusions (i.e., the accidental application of the wrong task) can occur. The present study investigated whether these task confusions result from failures of endogenous control (i.e., from ineffective task preparation) or from failures of exogenous control (i.e., from stimulus-induced task conflicts). The frequency of task confusions was estimated by considering the relative proportion of distractor errors, that is, errors that result when participants erroneously respond to the distractor associated with the alternative task. In Experiment 1, the efficiency of exogenous control was manipulated by varying the temporal order of target and distractor presentation. In Experiment 2, the efficiency of endogenous control was manipulated by varying the time available for preparing the task in advance. It turned out that only the efficiency of exogenous control but not the efficiency of endogenous control influenced the proportion of distractor errors. Accordingly, task confusions are more related to failures in exogenous control. [ABSTRACT FROM AUTHOR]

The current study assessed the effect that unexpected task constraint, following self-generated task choice, has on task switching performance. Participants performed a modified double-registration voluntary task switching procedure in which participants specified the task they wanted to perform, were presented with a cue that, on the majority of trials, confirmed the choice, and then performed the cued task. On a small portion of trials, participants were cued to perform a task that did not match their choice. Trials on which cues unexpectedly failed to match the chosen task were associated with costs. These costs were particularly large when participants chose to switch tasks but had to unexpectedly repeat the previous task. The results suggest that when participants choose to switch tasks, they prepare for that switch in anticipation of the stimulus, and the preparation is durable such that it cannot be readily undone. [ABSTRACT FROM PUBLISHER]

Cognitive control is thought to rely upon a set of distributed brain regions within frontoparietal cortex, but the functional contributions of these regions remain elusive. Here, we investigated the disruptive effects of transcranial magnetic stimulation (TMS) over the human prefrontal and parietal cortices in task preparation at different abstraction levels. While participants completed a task-switching paradigm that assessed the reconfiguration of task goals and response sets independently, TMS was applied over the left inferior frontal junction (IFJ) and over the left intraparietal sulcus (IPS) during task preparation. In Experiment 1, TMS over the IFJ caused interference with the updating of task goals, while leaving the updating of response sets unaffected. In Experiment 2, TMS over the IPS created the opposite pattern of results, perturbing only the ability to update response sets, but not task goals. Experiment 3 furthermore revealed that TMS over the IPS interfered with task goal updating when the pulses are delivered at a later point in time during preparation. This dissociation of abstract and action-related components not only reveals distinct cognitive control processes during task preparation, but also sheds new light on how prefrontal and parietal areas might work in concert to support flexible and goal-oriented control of behavior. [ABSTRACT FROM AUTHOR]

A central aspect of cognitive control is the capacity to anticipatorily prepare for specific task requirements prior to carrying out a task. To study the changes caused by task preparation, the cued task-switching paradigm has generally been used. While research on anticipatory control has long focused on general processing differences between switch and repeat trials, more recent research suggests that contextual variations strongly modulate such differences. In the current paper, we argue that anticipatory task set preparation strongly depends on contextual variables leading to different strategies to prepare for an upcoming task. We provide behavioral as well as neuroscientific evidence for this claim. Furthermore, we show that some preparatory processes are sensitive to strategic modulations whereas other preparatory processes are not. Based on this, we propose a functional dissociation within the fronto-parietal network involved in task preparation. [ABSTRACT FROM AUTHOR]

Recent neuroimaging studies have shown that working memory (WM) task difficulty can be decoded from patterns of brain activation in the WM network during preparation to perform those tasks. The inter-regional connectivity among the WM regions during task preparation has not yet been investigated. We examined this question using the graph modeling methods IMaGES and LOFS, applied to the previously published fMRI data of Manelis and Reder (2013). In that study, subjects performed 1-, 2-, and 3-back tasks. Each block of n-back was preceded by a preparation period and followed by a rest period. The analyses of task-related brain activity identified a network of 18 regions that increased in activation from 1- to 3-back (Increase network) and a network of 17 regions that decreased in activation from 1- to 3-back (Decrease network). The graph analyses revealed two types of connectivity sub-networks within the Increase and Decrease networks: "default" and "preparation-related." The "default" connectivity was present not only during task performance, but also during task preparation and during rest. We propose that this sub-network may serve as a core system that allows one to quickly activate cognitive, perceptual and motor systems in response to the relevant stimuli. The "preparation-related" connectivity was present during task preparation and task performance, but not at rest, and depended on the n-back condition. The role of this sub-network may be to pre-activate a connectivity "road map" in order to establish a top-down and bottom-up regulation of attention prior to performance on WM tasks. [ABSTRACT FROM AUTHOR]

The left dorsolateral prefrontal cortex (ldlPFC) has been highlighted as a key actor in human perceptual decision-making (PDM): It is theorized to support decision-formation independently of stimulus type or motor response. PDM studies however generally confound stimulus onset and task onset: when the to-be-recognized stimulus is presented, subjects know that a stimulus is shown and can set up processing resources-even when they do not know which stimulus is shown. We hypothesized that the ldlPFC might be involved in task preparation rather than decision-formation. To test this, we asked participants to report whether sequences of noisy images contained a face or a house within an experimental design that decorrelates stimulus and task onset. Decision-related processes should yield a sustained response during the task, whereas preparation-related areas should yield transient responses at its beginning. The results show that the brain activation pattern at task onset is strikingly similar to that observed in previous PDM studies. In particular, they contradict the idea that ldlPFC forms an abstract decision and suggest instead that its activation reflects preparation for the upcoming task. We further investigated the role of the fusiform face areas and parahippocampal place areas which are thought to be face and house detectors, respectively, that feed their signals to higher level decision areas. The response patterns within these areas suggest that this interpretation is unlikely and that the decisions about the presence of a face or a house in a noisy image might instead already be computed within these areas without requiring higher-order areas. Hum Brain Mapp 35:3170-3187, 2014. © 2013 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

An unresolved issue in the task-switching literature is whether preparatory reconfiguration occurs before a change of task. In this study, we used event-related potentials (ERPs) to determine whether preparatory reconfiguration occurs during two different task-switching procedures: voluntary and cued task switching. We focused on two ERP components that index different cognitive operations. The contingent negative variation (CNV) is a sensitive measure of a participant's preparedness to use a specific stimulus-response mapping. In contrast, the P3 indexes memory updating. We found a pronounced modulation of the CNV before voluntary task switches, but not before cued task switches. Instead, cued task switches were preceded by a larger P3, as compared with task repetitions. Our findings suggest that task set reconfiguration is carried out prior to voluntary task switches, whereas memory processes dominate cued task switches. [ABSTRACT FROM AUTHOR]

Abstract: Cognitive control processes refer to the ability to flexibly adapt one's thoughts and actions in the pursuit of an internal goal. Task preparation is a central aspect of cognitive control and has generally been studied using explicitly cued task-switching paradigms. Over the last decade, numerous fMRI studies have identified a fronto-parietal network to exhibit greater activity during the preparation of task switches than during the preparation of task repetitions, which is assumed to reflect endogenous cognitive control processes. There is, however, a huge variability in preparatory switch-specific brain activity reported in the imaging literature on task-switching. One factor that might explain this heterogeneity is the difference in switch probability across studies. In the current fMRI study, we examined which preparation-related cognitive control areas are susceptible to such contextual differences by manipulating the switch probability within subjects. In the low switch probability (30% switch trials) blocks, we found the frequently observed switch-related preparatory activation in fronto-parietal areas. In the high switch probability (50% switch trials) blocks, however, only part of these areas (more particularly the (pre-) SMA, extending into the dorsal ACC and the superior parietal lobule) showed higher activation in switch compared to repeat trials. The activation levels in the other areas (the lateral prefrontal cortex, inferior parietal lobule and middle temporal gyrus) were very similar for switch and repeat trials. Our results suggest a functional dissociation within the cognitive control network with some brain areas being sensitive to the switch probability context while others are not. [Copyright &y& Elsevier]

A large body of behavioural research has used the cued task-switching paradigm to characterize the nature of trial-by-trial preparatory adjustments that enable fluent task implementation when demands on cognitive flexibility are high. This work reviews the growing number of fMRI studies on the same topic, mostly focusing on the central hypothesis that preparatory adjustments should be indicated by enhanced prefrontal and parietal BOLD activation in task switch when compared with task repeat trials under conditions that enable advance task preparation. The evaluation of this straight-forward hypothesis reveals surprisingly heterogeneous results regarding both the precise localization and the very existence of switch-related preparatory activation. Explanations for these inconsistencies are considered on two levels. First, we discuss methodological issues regarding (i) the possible impact of different fMRI-specific experimental design modifications and (ii) statistical uncertainty in the context of massively multivariate imaging data. Second, we discuss explanations related to the multidimensional nature of task preparation itself. Specifically, the precise localization and the size of switch-related preparatory activation might depend on the differential interplay of hierarchical control via abstract task goals and attentional versus action-directed preparatory processes. We argue that different preparatory modes can be adopted relying either on advance goal activation alone or on the advance resolution of competition within action sets or attentional sets. Importantly, while either mode can result in a reduction of behavioral switch cost, only the latter two are supposed to be associated with enhanced switch versus repeat BOLD activation in prepared trial conditions. Hum Brain Mapp, 2013. © 2011 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

The aim of our study was to examine the role of task preparation and task inhibition in age-related task-switching deficits. In 2 experiments, we used a cuing paradigm with 3 tasks and manipulated the cue-stimulus interval (CSI). Additionally, switching among 3 tasks enabled us to examine n-2 task repetition costs, which reflect persisting inhibition of abandoned tasks. In Experiment 1, we found larger mixing costs (i.e., performance in mixed-task blocks vs. single-task blocks) in older adults than in young adults, and preparation effects were smaller in older adults than in young adults. In Experiment 2, where CSIs were blocked instead of randomly varied, we replicated reduced effects of task preparation in older adults. N-2 task repetition costs were not significant in Experiment 1 but significant in Experiment 2, and these costs did not differ across age groups in both experiments. The data suggest a task-preparation deficit in older adults that contributes to increased mixing costs in older adults. [ABSTRACT FROM AUTHOR]

Abstract: Recent neuroimaging evidence suggests that the dorsolateral prefrontal cortex is associated with creating deceptive responses. However, the neural basis of the preparatory processes that create deception has yet to be explored. Previous neuroimaging studies have demonstrated that the preparation for a certain task activates brain areas relevant to the execution of that task, leading to the question of whether dorsolateral prefrontal activity is observed during the preparation for deception. In the present study, we used functional magnetic resonance imaging (fMRI) to determine whether dorsolateral prefrontal activity, which increases during the execution of deception compared with the execution of truth-telling, also increases during the preparation for deception compared with the preparation for truth-telling. Our data show that the execution of deception was associated with increased activity in several brain regions, including the left dorsolateral prefrontal cortex, compared with truth-telling, confirming the contribution of this region to the production of deceptive responses. The results also reveal that the preparations for both deception and truth-telling were associated with increased activity in certain brain regions, including the left dorsolateral prefrontal cortex. These findings suggest that the preparations for truth-telling and deception make similar demands on the brain and that the dorsolateral prefrontal activity identified in the preparation phase is associated with general preparatory processes, regardless of whether one is telling a lie or the truth. [Copyright &y& Elsevier]

There are several International olympiads for secondary school students, but the five which are most widely recognised are those in mathematics, physics, chemistry, biology and informatics, in approximate order of founding. Most of these were originally founded under the auspices of UNESCO. Of these, the discipline most closely related to Informatics is mathematics, and in fact in several countries, for example Australia and Bulgaria (the latter of which can be credited as the founding country of IOI), the two olympiad programs are administered by the same organisation. The purpose of this paper is to compare the two olympiads in some detail, including tasks, topics, evaluation, etc. Despite the close relationship between the disciplines themselves, and the fact that there are similarities in the structure of the olympiads, in fact between all five, such as the medal structure, it is surprising also how different are the evolved traditions of IMO and IOI. [ABSTRACT FROM AUTHOR]

Abstract: The ability to flexibly shift between tasks is central to cognitive control, but whether the same brain mechanisms mediate shifting across different tasks is unknown. In this study, we investigated whether variations in stimulus-dimensions or response-mapping might influence task switching in terms of its preparatory processes, as reflected in cue-locked event-related potentials (ERPs), and its implementation processes, as reflected in stimulus-locked ERPs. Participants judged pairs of digits as same or different in one of two conditions. In one condition, the task-relevant stimulus-dimension was either repeated or switched across trials while the response-mapping rule was kept constant. In the other condition, the task-relevant stimulus-dimension was kept constant while the response-mapping rule was repeated or switched across trials. The length of the preparatory interval was manipulated. Data revealed switch-related preparatory ERP components (including N2 and a late slow positivity) that were associated with both types of task shifting and an N400-like negativity that distinguished between the two types. Several switch-related implementation ERP components associated with both types of task shifting were found at posterior sites. Distinct frontal modulations of the N1, P2, and N2 were found to associate with the implementation of the response-mapping shift, whereas a slow positivity was associated with the implementation of the stimulus-dimension shift. Therefore, this study demonstrates that there are shared and distinct processes across different types of task shifting. Finally, because the same transition-cue was used for different task shifts, the distinct processes cannot be explained simply by differences in cue processing. [Copyright &y& Elsevier]

Objective: The nature of increased-age-related dual-task interference was examined during a driving-like dual task in the laboratory.Background: Previous research revealed age-related deficits in dual tasks especially when cognitive and motor demands are involved. The specific contributions of sensory input, working memory demands, and/or coordination of motor responses to dual-task interference are not clear and should be clarified in the present study.Method: Younger and older participants performed a driving-like tracking task and a visually cued attention task within a dual task. Behavioral and electrophysiological data were recorded during task performance.Results: Overall tracking performance was lower for the older versus younger participants. This age-related decline was particularly pronounced in the time interval after the stimulus when the attention task demanded a motor response. In contrast, older participants tracked relatively better than the younger participants in the time interval preceding the stimulus. In the attention task, the older versus younger participants showed increased responses times and rates of false alarms and misses, suggesting a deficit in retaining the context in the cue-stimulus interval. The electroencephalogram data suggest that the older participants invested more resources than the younger participants in dual-task management during the cue-stimulus interval.Conclusion: Evidence was found for increased motor interference and a deficient context processing as well as for an increased investment of processing resources in the older compared with the younger group.Application: The results suggest that in-vehicle information systems for older drivers should be designed to support cue maintenance and that simultaneous motor demands should not be required. [ABSTRACT FROM AUTHOR]

Abstract: The goal of the study was to explore the time-course of the asymmetrical “local” switch cost observed in task switching. We investigated event-related potentials induced by cue and target processing when participants were engaged in a card-sorting switching task. Participants were instructed to match each card (target) following one of two possible task rules, the color or the form. The correct task rule changed unpredictably after a variable number of trials, and was signalled by cues indicating to switch or repeat the previous task rule. We observed that transition type (switch versus repeat) and task rule (color versus form) influenced both cue and target processing. Interestingly, the interaction between transition type and task rule, indicating an asymmetry in the local switch cost, affected the brain responses during target processing but not during cue processing. These results suggest that the asymmetry in the local switch cost relates to task execution processes. [Copyright &y& Elsevier]

Abstract: In a cross-sectional, electrophysiological study 91 workers of a big car factory performed a series of switch tasks to assess their cognitive control functions. Four groups of workers participated in the study: 23 young and 23 middle aged assembly line employees and 22 young and 23 middle aged employees with flexible job demands like service and maintenance. Participants performed three digit categorisation tasks. In addition to single task blocks, a cue-based (externally guided) and a memory-based (internally guided) task switch block was administered. Compared to young participants, older ones showed the typical RT-decline. No differences between younger and older participants regarding the local switch costs could be detected despite the source of the current task information. In contrast, whereas the groups did not differ in mixing costs in the cued condition, clear performance decrements in the memory-based mixing block were observed in the group of older employees with repetitive work demands. These findings were corroborated by a number of electrophysiological results showing a reduced CNV suggesting an impairment of task specific preparation, an attenuated P3b suggesting reduced working memory capacity and a decreased Ne suggesting deficits in error monitoring in older participants with repetitive job demands. The results are compatible with the assumption that long lasting, unchallenging job demands may induce several neurocognitive impairments which are already evident in the early fifties. Longitudinal studies are needed to confirm this assumption. [ABSTRACT FROM AUTHOR]

The relation of aerobic fitness to task preparation was examined in a sample of young adults separated into higher- and lower-fit groups according to their maximal oxygen consumption. Participants performed a modified Sternberg working memory task under speed and accuracy instructions while measures of task performance and contingent negative variation (CNV) were collected. Analyses revealed no significant fitness differences between groups on task performance measures. However, frontal CNV amplitude was significantly larger for lower-fit participants compared to higher-fit participants during the speed instructions, an effect not found for the accuracy instructions. These results suggest that lower-fit individuals may rely to a greater extent on cognitive control processes to respond under speeded conditions, whereas higher-fit individuals may maintain a more constant level of control irrespective of the task instructions. [ABSTRACT FROM AUTHOR]

Abstract: To isolate the neural correlates for task rule activation from those related to general task preparation, the effect of a cue explicitly specifying the S–R correspondences (rule-cue) was contrasted with the effects of a cue specifying only the task to performed (task-cue). While the task-cue provides merely information about the type of task, the rule-cue is explicit about both the task type and the task rule (i.e., the set of S–R correspondences). The rule-cue was expected to activate the task rule more efficiently in the preparation period (prior to target presentation); by contrast, in the task-cue condition, part of the task rule activation was expected to be postponed into the task execution period (following the presentation of the target). In an event-related fMRI experiment, we found the right anterior and middle parts of the middle frontal and superior frontal gyri, the right inferior frontal junction, the pre-SMA, as well as the right superior and inferior parietal lobes to show larger activation elicited by the rule-cue than by the task-cue prior to target presentation. Conversely, the results revealed larger activations in these regions in the task-cue than in the rule-cue condition during the task execution period. In summary, this study identified some of the neural correlates of task rule activation and showed that these are a subset of the general task preparation network. [Copyright &y& Elsevier]

Abstract: By using event-related potentials (ERPs) the present study examines if age-related differences in preparation and processing especially emerge during divided attention. Binaurally presented auditory cues called for focused (valid and invalid) or divided attention to one or both ears. Responses were required to subsequent monaurally presented valid targets (vowels), but had to be suppressed to non-target vowels or invalidly cued vowels. Middle-aged participants were more impaired under divided attention than young ones, likely due to an age-related decline in preparatory attention following cues as was reflected in a decreased CNV. Under divided attention, target processing was increased in the middle-aged, likely reflecting compensatory effort to fulfill task requirements in the difficult condition. Additionally, middle-aged participants processed invalidly cued stimuli more intensely as was reflected by stimulus ERPs. The results suggest an age-related impairment in attentional preparation after auditory cues especially under divided attention and latent difficulties to suppress irrelevant information. [Copyright &y& Elsevier]

Abstract: Physical activity and aerobic exercise in particular, promotes health and effective cognitive functioning. To elucidate mechanisms underlying the beneficial effects of physical fitness and acute exercise, behavioral and electrophysiological indices of task preparation and response inhibition as a part of executive functions were assessed in a modified version of an Eriksen flanker task subsequent to an acute bout of aerobic exercise and a period of rest, respectively. 35 higher- and lower-fit adolescents between 13 and 14 years of age participated in a controlled cross-over study design. Results indicate that higher-fit individuals show significantly greater CNV amplitudes, reflecting enhanced task preparation processes, as well as decreased amplitudes in N2, indexing more efficient executive control processes. P3 amplitudes associated with the allocation of attentional and memory control neither showed influences of physical fitness nor the acute bout of exercise. Furthermore, acute aerobic exercise was not related to any of the dependent measures. The current findings suggest that physical fitness, but not an acute bout of aerobic exercise enhances cognitive processing by increasing attentional allocation to stimulus encoding during task preparation. [Copyright &y& Elsevier]

The nomological network of the technology acceptance model is expanded through the addition of affective and task-preparation variables as antecedents to traditional predictors of technology acceptance:output quality, result demonstrability, and ease of use. An empirical study involving a visual/simulation information system, set in the domain of retail merchandise planning, finds that negative affectivity (NA) is a consistent and strong negative antecedent to perceptions of output quality, result demonstrability, and ease of use. In contrast, positive affectivity (PA) is a significant and positive antecedent to ease of use, but not necessarily a significant antecedent to either output quality or result demonstrability. A new construct developed from the job characteristics literature-perceived task preparation-measured the subject ~ perceptions of the pre-system usage training, which included task design and modeling instruction, scenarios of activities within the prospective information system, discussions and review of the system documentation, and highly structured, pm-task system use activities. Perceived task preparation was found to be a significant and strong positive indicator of computer self-efficacy. [ABSTRACT FROM AUTHOR]

Abstract: The present study examined whether task preparation had an equivalent beneficial effect for both switch and repeat trials in the context of a task switching paradigm. A pair-wise task-switching paradigm was used where each trial was comprised of two tasks that were either the same (task repeat) or different (task switch). The effect of preparation was manipulated so that participants either performed pure repeat trials or pure switch trials in separate blocks (foreknowledge conditions) or performed both switch and repeat trials within the same block (non-foreknowledge conditions). In addition, the time interval between the response to the first task and the onset of the next task''s stimulus (response-stimulus interval, RSI) was set at either 300 ms or 600 ms. Both stimulus-locked and response-locked lateralized readiness potentials were measured to examine at what stage in time that task preparation affects the task performance. The results showed that task preparation had the same amount of beneficial effect on the stage of response selection for both switch and repeat trials, regardless of whether the RSI was short or long. [Copyright &y& Elsevier]

Abstract: This study investigates the ability to use foreknowledge in preparation of cognitive processes in young and older participants and in PD patients. Additionally, we test the hypothesis that age-associated cognitive deficits in task switching reflect a dopaminergic dysfunction that accompanies healthy aging. To this end, we use a task-switching paradigm that (i) is known to be highly sensitive for dopaminergic dysfunction in the frontostriatal loops and (ii) can be applied with predictable and unpredictable switch and non-switch trials to assess the effect of task foreknowledge. Our results show that young participants benefit from foreknowledge and are thus able to prepare for predictable cognitive processes. Older participants have lost their ability to benefit from foreknowledge, which seems to be an effect of healthy aging. In predictable trials, the performance of PD patients did not differ from that of controls. Thus, PD patients do not show an additional deficit in the preparation of predictable cognitive switches. However, PD patients are specifically impaired in unpredictable trials compared to controls. We suggest that this result can be explained by the uncertainty about the next task in the unpredictable condition which prevents an automatic process and demands more attention. Furthermore, our results of older participants do not resemble the deficits seen in PD patients in task-switching behavior. This argues for different mechanisms that underlie the changes in task-switching behavior in healthy aging and PD. [Copyright &y& Elsevier]

Three experiments examined the implications of adding a fourth preparation stage to the encoding-retention-retrieval stage analysis of memory. Action memory was selected as the research domain. The results demonstrated that systematic variation of the preparation stage yields new insights about enactment effects in memory. Together with effects of enactment in the preparatory stage, enactment was also shown to give differential effects in encoding and retrieval, with interactions between these three factors. The experimental results were discussed in relation to a strategy processing interpretation of action memory. [ABSTRACT FROM AUTHOR]