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Cognitive Control (cognitive + control)
Selected AbstractsThe timing of cognitive control in partially incongruent categorizationHUMAN BRAIN MAPPING, Issue 9 2008Antao Chen Abstract We designed a novel task, partially incongruent categorization (PIC), to examine the timing of cognitive control. In the PIC task, participants categorized the probe stimulus according to a specific concept, and the number of features corresponding to the concept was varied. When there was one feature (c1 condition), the probe would elicit only categorization, but when there was more than one feature (c2 and c3 conditions), the probe would also elicit cognitive control. Here, the high temporal resolution of event-related potentials (ERPs) was utilized to investigate the temporal patterns of activity during conflict detection and control. Cognitive control elicited a N2 that was much larger in response to c2 and c3 than c1 in stimulus-locked waveforms, and no difference was evident between c2 and c3. The N2 was followed by a P3 that was much less on c2 and c3 than c1 trials, with no difference between c2 and c3. A dipole source analysis for two difference waves, c2,c1 and c3,c1, further showed that the corresponding dipoles of the N2 and P3 in the cognitive control conditions were in the anterior cingulate cortex (ACC) and prefrontal cortex (PFC), respectively. Taken together, the present findings support that ERP components in response to the PIC task reflect the time course of cognitive control: the N2 responds to conflict information and subsequently activates the P3 to control this conflict. The connection between the ACC and PFC is supported by their sequential activation within trials. Hum Brain Mapp, 2008. © 2007 Wiley-Liss, Inc. [source] Corticolimbic dysregulation and chronic methamphetamine abuseADDICTION, Issue 2007Kate Baicy ABSTRACT Aims This review aims to present and interpret evidence that methamphetamine dependence is associated with disorder of brain function that is required for top-down control of behavior. Approach Presented here are findings from brain imaging studies of human research participants with histories of chronic methamphetamine abuse in the context of functional consequences and implications for treatment of their dependence on methamphetamine. Findings Brain imaging studies have revealed differences in the brains of research participants who have used methamphetamine chronically and then abstained from taking the drug, compared with healthy control subjects. These abnormalities are prominent in cortical and limbic systems, and include deficits in markers of dopaminergic and serotonergic neurotransmitter systems, differences in glucose metabolism and deficits in gray matter. These abnormalities accompany cognitive deficits, including evidence of impaired inhibitory control. Conclusion Cortical deficits in abstinent methamphetamine abusers can affect a wide range of functions that can be important for success in maintaining drug abstinence. These include but are not limited to modulation of responses to environmental stimuli as well as internal triggers that can lead to craving and relapse. Potential therapies may combine behavioral approaches with medications that can improve cognitive control. [source] Effects of dopamine-related gene,gene interactions on working memory component processesEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 5 2009Christine Stelzel Abstract Dopamine modulates complex cognitive functions like working memory and cognitive control. It is widely accepted that an optimal level of prefrontal dopamine supports working memory performance. In the present study we used a molecular genetic approach to test whether the optimal activity of the dopamine system for different component processes of working memory is additionally related to the availability of dopamine D2 receptors. We sought evidence for this assumption by investigating the interaction effect (epistasis) of variations in two dopaminergic candidate genes: the catechol- O -methyltransferase (COMT) Val158Met polymorphism, which has been shown to influence prefrontal dopamine concentration, and the DRD2/ANKK1-Taq-Ia polymorphism, which has been related to the density of D2 receptors. Our results show that COMT effects on working memory performance are modulated by the DRD2/ANKK1-TAQ-Ia polymorphism and the specific working memory component process under investigation. Val, participants , supposedly characterized by increased prefrontal dopamine concentrations , outperformed Val+ participants in the manipulation of working memory contents, but only when D2 receptor density could be considered to be high. No such effect was present for passive maintenance of working memory contents or for maintenance in the face of distracting information. This beneficial effect of a balance between prefrontal dopamine availability and D2 receptor density reveals the importance of considering epistasis effects and different working memory subprocesses in genetic association studies. [source] Brain network dynamics during error commissionHUMAN BRAIN MAPPING, Issue 1 2009Michael C. Stevens Abstract Previous studies suggest that the anterior cingulate and other prefrontal brain regions might form a functionally-integrated error detection network in the human brain. This study examined whole brain functional connectivity to both correct and incorrect button presses using independent component analysis (ICA) of functional magnetic resonance imaging (fMRI) data collected from 25 adolescent and 25 adult healthy participants (ages 11,37) performing a visual Go/No-Go task. Correct responses engaged a network comprising left lateral prefrontal cortex, left postcentral gyrus/inferior parietal lobule, striatum, and left cerebellum. In contrast, a similar network was uniquely engaged during errors, but this network was not integrated with activity in regions believed to be engaged for higher-order cognitive control over behavior. A medial/dorsolateral prefrontal-parietal neural network responded to all No-Go stimuli, but with significantly greater activity to errors. ICA analyses also identified a third error-related circuit comprised of anterior temporal lobe, limbic, and pregenual cingulate cortices, possibly representing an affective response to errors. There were developmental differences in error-processing activity within many of these neural circuits, typically reflecting greater hemodynamic activation in adults. These findings characterize the spatial structure of neural networks underlying error commission and identify neurobiological differences between adolescents and adults. Hum Brain Mapp 2009. © 2007 Wiley-Liss, Inc. [source] The timing of cognitive control in partially incongruent categorizationHUMAN BRAIN MAPPING, Issue 9 2008Antao Chen Abstract We designed a novel task, partially incongruent categorization (PIC), to examine the timing of cognitive control. In the PIC task, participants categorized the probe stimulus according to a specific concept, and the number of features corresponding to the concept was varied. When there was one feature (c1 condition), the probe would elicit only categorization, but when there was more than one feature (c2 and c3 conditions), the probe would also elicit cognitive control. Here, the high temporal resolution of event-related potentials (ERPs) was utilized to investigate the temporal patterns of activity during conflict detection and control. Cognitive control elicited a N2 that was much larger in response to c2 and c3 than c1 in stimulus-locked waveforms, and no difference was evident between c2 and c3. The N2 was followed by a P3 that was much less on c2 and c3 than c1 trials, with no difference between c2 and c3. A dipole source analysis for two difference waves, c2,c1 and c3,c1, further showed that the corresponding dipoles of the N2 and P3 in the cognitive control conditions were in the anterior cingulate cortex (ACC) and prefrontal cortex (PFC), respectively. Taken together, the present findings support that ERP components in response to the PIC task reflect the time course of cognitive control: the N2 responds to conflict information and subsequently activates the P3 to control this conflict. The connection between the ACC and PFC is supported by their sequential activation within trials. Hum Brain Mapp, 2008. © 2007 Wiley-Liss, Inc. [source] Involvement of the inferior frontal junction in cognitive control: Meta-analyses of switching and Stroop studiesHUMAN BRAIN MAPPING, Issue 1 2005Jan Derrfuss Abstract There is growing evidence that a specific region in the posterior frontolateral cortex is involved intimately in cognitive control processes. This region, located in the vicinity of the junction of the inferior frontal sulcus and the inferior precentral sulcus, was termed the inferior frontal junction (IFJ). The IFJ was shown to be involved in the updating of task representations and to be activated commonly in a within-subject investigation of a task-switching paradigm, the Stroop task, and a verbal n-back task. Here, we investigate the involvement of the IFJ in cognitive control by employing a meta-analytic approach. Two quantitative meta-analyses of functional magnetic resonance imaging (fMRI) studies were conducted. One meta-analysis included frontal activations from task-switching, set-shifting, and stimulus,response (S,R) reversal studies, the other included frontal activations from color,word Stroop studies. Results showed highly significant clustering of activations in the IFJ in both analyses. These results provide strong evidence for the consistent involvement of the IFJ in both switching and Stroop paradigms. Furthermore, they support our concept of areal specialization in the frontolateral cortex, which posits that it is not only the middorsolateral part that plays an important role in cognitive control, but also the IFJ. Finally, our results demonstrate how quantitative meta-analyses can be used to test hypotheses about the involvement of specific brain regions in cognitive control. Hum Brain Mapp 25:22,34, 2005. © 2005 Wiley-Liss, Inc. [source] A comparative simulation study of work processes in autonomous production cellsHUMAN FACTORS AND ERGONOMICS IN MANUFACTURING & SERVICE INDUSTRIES, Issue 1 2002Christopher Schlick An approach to human-centered design and assessment of work processes in flexible manufacturing systems with the help of dynamic task networks is presented. To model and simulate the task networks, the method of timed colored Petri Nets is used. Two task networks are developed. The first task network is a model of work processes in Autonomous Production Cells (APCs). The second task network represents work processes in conventional Computer Numerically Controlled (CNC)-based manufacturing systems. The material processing technology is associated with 5-axis milling. The values of attributes of task elements were acquired empirically on a fine-grained level with reference to a sample milling order. Comparative hypotheses regarding time-on-task, supervisory control functions, levels of cognitive control, human error (HE), and labor division were then formulated. To test these hypotheses, several simulation experiments were conducted. The results from inferential statistics show that single-operator APCs have a 30% higher efficiency in relation to total time-on-task. Moreover, the level of cognitive control is significantly shifted toward rule- and knowledge-based behavior. Surprisingly, the simulation of minor HE does not demonstrate a significantly worse performance from APCs. A simulated labor division among central process planner and production operator allows an additional efficiency improvement of approximately 15%. However, the labor division has two important drawbacks: first, a sequential incompleteness of operators' task spectrum occurs; second, the operator has to cope with hierarchical task incompleteness. Finally, a sensitivity analysis was carried out to investigate the effects of varying lot sizes and number of processed orders. © 2002 John Wiley & Sons, Inc. [source] The Effects of Fetal Alcohol Syndrome on Response Execution and Inhibition: An Event-Related Potential StudyALCOHOLISM, Issue 11 2009Matthew J. Burden Background:, Both executive function deficits and slower processing speed are characteristic of children with fetal alcohol exposure, but the temporal dynamics of neural activity underlying cognitive processing deficits in fetal alcohol spectrum disorder have rarely been studied. To this end, event-related potentials (ERPs) were used to examine the nature of alcohol-related effects on response inhibition by identifying differences in neural activation during task performance. Methods:, We recorded ERPs during a Go/No-go response inhibition task in 2 groups of children in Cape Town, South Africa (M age = 11.7 years; range = 10 to 13),one diagnosed with fetal alcohol syndrome (FAS) or partial FAS (FAS/PFAS; n = 7); the other, a control group whose mothers abstained or drank only minimally during pregnancy (n = 6). Children were instructed to press a "Go" response button to all letter stimuli presented except for the letter "X," the "No-go" stimulus, which occurred relatively infrequently. Results:, Task performance accuracy and reaction time did not differ between groups, but differences emerged for 3 ERP components,P2, N2, and P3. The FAS/PFAS group showed a slower latency to peak P2, suggesting less efficient processing of visual information at a relatively early stage (,200 ms after stimulus onset). Moreover, controls showed a larger P2 amplitude to Go versus No-go, indicating an early discrimination between conditions that was not seen in the FAS/PFAS group. Consistent with previous literature on tasks related to cognitive control, the control group showed a well-defined, larger N2 to No-go versus Go, which was not evident in the FAS/PFAS group. Both groups showed the expected larger P3 amplitude to No-go versus Go, but this condition difference persisted in a late slow wave for the FAS/PFAS group, suggesting increased cognitive effort. Conclusions:, The timing and amplitude differences in the ERP measures suggest that slower, less efficient processing characterizes the FAS/PFAS group during initial stimulus identification. Moreover, the exposed children showed less sharply defined components throughout the stimulus and response evaluation processes involved in successful response inhibition. Although both groups were able to inhibit their responses equally well, the level of neural activation in the children with FAS/PFAS was greater, suggesting more cognitive effort. The specific deficits in response inhibition processing at discrete stages of neural activation may have implications for understanding the nature of alcohol-related deficits in other cognitive domains as well. [source] Altered Impulse Control in Alcohol Dependence: Neural Measures of Stop Signal PerformanceALCOHOLISM, Issue 4 2009Chiang-shan Ray Li Background:, Altered impulse control has been implicated in the shaping of habitual alcohol use and eventual alcohol dependence. We sought to identify the neural correlates of altered impulse control in 24 abstinent patients with alcohol dependence (PAD), as compared to 24 demographics matched healthy control subjects (HC). In particular, we examined the processes of risk taking and cognitive control as the neural endophenotypes of alcohol dependence. Methods:, To this end, functional magnetic resonance imaging (fMRI) was conducted during a stop signal task (SST), in which a procedure was used to elicit errors in the participants. The paradigm allowed trial-by-trial evaluation of response inhibition, error processing, and post-error behavioral adjustment. Furthermore, by imposing on the subjects to be both fast and accurate, the SST also introduced a distinct element of risk, which participants may or may not avert during the task. Brain imaging data were analyzed with Statistical Parametric Mapping in covariance analyses accounting for group disparity in general performance. Results:, The results showed that, compared to HC, PAD demonstrated longer go trial reaction time (RT) and higher stop success rate (SS%). HC and PAD were indistinguishable in stop signal reaction time (SSRT) and post-error slowing (PES). In a covariance analysis accounting for go trial RT and SS%, HC showed greater activity in the left dorsolateral prefrontal cortex than PAD, when subjects with short and long SSRT were contrasted. By comparing PAD and HC directly during stop errors (SE), as contrasted with SS, we observed greater activity in PAD in bilateral visual and frontal cortices. Compared to HC, PAD showed less activation of the right dorsolateral prefrontal cortex during PES, an index of post-error behavioral adjustment. Furthermore, PAD who showed higher alcohol urge at the time of the fMRI were particularly impaired in dorsolateral prefrontal activation, as compared to those with lower alcohol urge. Finally, compared to HC subjects, PAD showed less activity in cortical and subcortical structures including putamen, insula, and amygdala during risk-taking decisions in the SST. Conclusion:, These preliminary results provided evidence for altered neural processing during impulse control in PAD. These findings may provide a useful neural signature in the evaluation of treatment outcomes and development of novel pharmacotherapy for alcohol dependence. [source] Acquisition of Literacy in Bilingual Children: A Framework for ResearchLANGUAGE LEARNING, Issue 2007Ellen Bialystok Much of the research that contributes to understanding how bilingual children become literate is not able to isolate the contribution of bilingualism to the discussion of literacy acquisition for these children. This article begins by identifying three areas of research that are relevant to examining literacy acquisition in bilinguals, explaining the contribution of each, and associating each type of research with a skill required by monolingual children in becoming literate. Three prerequisite skills for the acquisition of literacy are competence with the oral language, understanding of symbolic concepts of print, and establishment of metalinguistic awareness. A review of the literature explores the extent to which these skills that influence literacy acquisition in monolinguals develop differently for bilingual children. The conclusion is that the relation between bilingualism and the development of each of the three skills is different, sometimes indicating an advantage (concepts of print), sometimes a disadvantage (oral language competence), and sometimes little difference (metalinguistic concepts) for bilingual children. Therefore, bilingualism is clearly a factor in children's development of literacy, but the effect of that factor is neither simple nor unitary. Since the publication of this article, our research has continued to explore the themes set out in this framework and provided more detail for the description of how bilingualism affects the acquisition of literacy. Two important advances in this research are the finding that some aspects of reading ability, notably phonological awareness, are rooted in general cognitive mechanisms and transfer easily across languages, whereas others, such as decoding, are more language dependent and language-specific and need to be relearned with each new writing system (Bialystok, Luk, & Kwan, 2005). Second, writing systems and the differences between them have a greater impact on children's acquisition of literacy than previously believed. Not surprisingly, this relation has been found for emerging ability with phonological awareness (Bialystok, McBride-Chang, & Luk, 2005) but, more surprisingly, has recently been shown to have a subtle influence on children's emerging concepts of print (Bialystok & Luk, in press). The interpretation that bilingualism must be considered in terms of both advantages and disadvantages has also been pursued in studies of cognitive and linguistic processing in adults. Recent research has shown that adult bilinguals display disadvantages on tasks measuring lexical retrieval and fluency (Michael & Gollan, 2005) but advantages on tasks assessing cognitive control of attention (Bialystok, Craik, Klein, & Viswanathan, 2004). This approach leads to a more detailed and, ultimately, more accurate description of how bilingualism affects cognitive performance. [source] Neurocognitive components of the behavioral inhibition and activation systems: Implications for theories of self-regulationPSYCHOPHYSIOLOGY, Issue 1 2008David M. Amodio Abstract We examined the neurocognitive correlates of the Behavioral Inhibition and Behavioral Activation Systems (BIS/BAS) in an effort to clarify ambiguities concerning interpretations of BIS as reflecting inhibition versus avoidance. We hypothesized that self-reported BIS should relate to neural mechanisms associated with conflict monitoring, whereas self-reported BAS should be associated with neural correlates of approach motivation. Consistent with these predictions, higher self-reported BIS was uniquely related to the N2 event-related potential on No-Go trials of a Go/No-Go task, linking BIS with conflict monitoring and sensitivity to No-Go cues. Higher BAS was uniquely related to greater left-sided baseline frontal cortical asymmetry associated with approach orientation. Implications for theories of self-regulation involving conflict monitoring, cognitive control, and approach/avoidance motivation are discussed. [source] Reduced activation in lateral prefrontal cortex and anterior cingulate during attention and cognitive control functions in medication-naïve adolescents with depression compared to controlsTHE JOURNAL OF CHILD PSYCHOLOGY AND PSYCHIATRY AND ALLIED DISCIPLINES, Issue 3 2009Rozmin Halari Background:, There is increasing recognition of major depressive disorder (MDD) in adolescence. In adult MDD, abnormalities of fronto-striatal and fronto-cingulate circuitries mediating cognitive control functions have been implicated in the pathogenesis and been related to problems with controlling negative thoughts. No neuroimaging studies of cognitive control functions, however, exist in paediatric depression. This study investigated whether medication-naïve adolescents with MDD show abnormal brain activation of fronto-striatal and fronto-cingulate networks when performing tasks of attentional and cognitive control. Methods:, Event-related functional magnetic resonance imaging was used to compare brain activation between 21 medication-naïve adolescents with a first-episode of MDD aged 14,17 years and 21 healthy adolescents, matched for handedness, age, sex, demographics and IQ. Activation paradigms were tasks of selective attention (Simon task), attentional switching (Switch task), and motor response inhibition and error detection (Stop task). Results:, In all three tasks, adolescents with depression compared to healthy controls demonstrated reduced activation in task-relevant right dorsolateral (DLPFC), inferior prefrontal cortex (IFC) and anterior cingulate gyrus (ACG). Additional areas of relatively reduced activation were in the parietal lobes during the Stop and Switch tasks, putamen, insula and temporal lobes during the Switch task and precuneus during the Simon task. Conclusions:, This study shows first evidence that medication-naïve adolescents with MDD are characterised by abnormal function in ACG and right lateral prefrontal cortex during tasks of attention and performance monitoring, suggesting an early pathogenesis of these functional abnormalities attributed to MDD. [source] Brain,computer interfacing based on cognitive controlANNALS OF NEUROLOGY, Issue 6 2010Mariska J. Vansteensel PhD Objective Brain,computer interfaces (BCIs) translate deliberate intentions and associated changes in brain activity into action, thereby offering patients with severe paralysis an alternative means of communication with and control over their environment. Such systems are not available yet, partly due to the high performance standard that is required. A major challenge in the development of implantable BCIs is to identify cortical regions and related functions that an individual can reliably and consciously manipulate. Research predominantly focuses on the sensorimotor cortex, which can be activated by imagining motor actions. However, because this region may not provide an optimal solution to all patients, other neuronal networks need to be examined. Therefore, we investigated whether the cognitive control network can be used for BCI purposes. We also determined the feasibility of using functional magnetic resonance imaging (fMRI) for noninvasive localization of the cognitive control network. Methods Three patients with intractable epilepsy, who were temporarily implanted with subdural grid electrodes for diagnostic purposes, attempted to gain BCI control using the electrocorticographic (ECoG) signal of the left dorsolateral prefrontal cortex (DLPFC). Results All subjects quickly gained accurate BCI control by modulation of gamma-power of the left DLPFC. Prelocalization of the relevant region was performed with fMRI and was confirmed using the ECoG signals obtained during mental calculation localizer tasks. Interpretation The results indicate that the cognitive control network is a suitable source of signals for BCI applications. They also demonstrate the feasibility of translating understanding about cognitive networks derived from functional neuroimaging into clinical applications. ANN NEUROL 2010 [source] Emotional vulnerability and cognitive control in patients with bipolar disorder and their healthy siblings: a pilot studyACTA NEUROPSYCHIATRICA, Issue 2 2010Kathrin Houshmand Scheuch K, Bräunig P, Gauggel S, Kliesow K, Sarkar R, Krüger S. Emotional vulnerability and cognitive control in patients with bipolar disorder and their healthy siblings: a pilot study. Objective: There is evidence that, even in remission, patients with bipolar disorder (BD) have deficits in cognitive function and emotional regulation. Siblings of patients with BD are also reported to exhibit minor dysfunction in neuropsychological domains. In this study, we examined the interference of acute mood state with reaction time (RT) and response inhibition in euthymic patients with BD, in their healthy siblings and in healthy controls. Methods: A total of 34 patients with bipolar I disorder, 22 healthy siblings and 33 healthy controls performed a stop-signal paradigm after induction of a transient intense sadness and a relaxed mood state. The differences in RT and the response inhibition were compared between the groups. Results: Euthymic patients with BD displayed a higher emotional reactivity compared with their siblings and with controls. Compared with controls, patients with BD showed longer RTs in a relaxed mood state and a delay in response inhibition during emotional activation. Conclusions: The present study provides evidence for the clinical observation that patients with BD have shorter RTs when in a state of emotional arousal rather than in a relaxed state. Inhibitory deficits in these patients may be because of a too strong emotional arousal. The results show that in patients with BD, relaxation and emotional arousal are inversely associated with performance in a neuropsychological task. This is in contrast to findings in healthy individuals suggesting a dysbalance in emotional regulation in these patients. [source] |