Executive Control Components Research Articles

Working memory in school-aged children with attention-deficit/hyperactivity disorder combined type: Are deficits modality specific and are they independent of impaired inhibitory control?

This study examines differences between children with attention-deficit/ hyperactivity disorder combined type (ADHD-C) and normal controls on verbal and visuospatial working-memory (WM) tasks. The extent to which WM deficits in children with ADHD-C are independent of impaired inhibitory control was also examined. Two groups of 7- to 12-year-old boys participated in this study. The first group included 31 boys diagnosed with ADHD-C, and the second group included 34 boys without ADHD. Various verbal and visuospatial WM tasks and two inhibitory control tasks—prepotent response inhibition and interference control—were used. Overall, our results suggest impaired verbal and visuospatial WM processes in children with ADHD-C, as well as a lower level of performance on prepotent response inhibition. WM deficits in ADHD have previously been suggested to be particularly salient in the spatial domain; our results instead showed the largest effect for a verbal WM task thought to put heavy load on the executive or attentional control component of the WM system. An interpretation of this finding is that it is variation in terms of difficulty level or load on the executive WM processes, rather than variation in modality (verbal versus visuospatial), that is important in demonstrating WM deficits in ADHD-C. Finally, findings from logistic regression analyses showed that deficits in WM and inhibitory control seem to be semi-independent in children with ADHD-C, at least with regard to the elementary school age.

Functional relationships between serum total cholesterol levels, executive control, and sustained attention

This study investigated the potential relationship between serum total cholesterol (TC) and two specific aspects of cognition (executive control and sustained attention) in a non-elderly sample, after controlling for life stress and several sociodemographic and health variables. For each participant (n = 46), measurements of TC, physical health, and life stress were obtained, and executive control and sustained attention were assessed using the Tower of London and the Digit Vigilance Test. The outcomes of these cognitive assessments were correlated with TC, and a covariate-adjusted analysis was performed. After controlling for several co-variates, TC was found to be significantly negatively associated with components of executive control and sustained attention. Because these cognitive functions are crucial in the moment-to-moment regulation of behavior, elevated TC may have negative behavioral consequences in everyday life situations.

The influence of working memory and other cognitive functions on task switching: Evidence from healthy aging and mild cognitive impairment

Event Abstract Back to Event The influence of working memory and other cognitive functions on task switching: Evidence from healthy aging and mild cognitive impairment Natalie Phillips1, 2, 3*, P. Goffaux4 and M. Sinai1, 2 1 Concordia University, Department of Psychology, Canada 2 Concordia University, Centre for Research in Human Development, Canada 3 Lady Davis Institute for Medical Research/Jewish General Hospital, Canada 4 University of Sherbrooke, Canada Efficient switching between tasks requires that attentional, preparatory, and working memory resources be mobilized. Because these processes represent components of executive control, it is not surprising to find age differences in task-switching. In this talk I will present behavioural and event-related brain potential (ERP) data on task switching performance in young adults, healthy older adults, and patients with mild cognitive impairment (MCI; a group at high risk for developing Alzheimer’s disease). In one study (Goffaux, Phillips, et al., in press), we demonstrate that individual differences in working memory are an important determinant of the performance of older adults during task switching. Specifically, older adults with high working memory performed similarly to younger adults, although their pattern of electrical brain activity differed. Older adults with low working memory performed more poorly and exhibited yet another pattern of electrical brain activity. In a second study (Sinai & Phillips, in preparation), we investigated task switching performance in MCI patients and healthy elderly controls. Despite the mild difficulties these patients show on a battery of neuropsychological tests, a significant number showed marked impairment on a set switching task and were unable to complete it without external support. However, other patients were able to perform the task and did not differ from their controls in terms of reaction time, accuracy, or ERPs. Taken together, these data indicate that task switching performance is sensitive to age and neurological status and appears dependent on other important cognitive abilities. Conference: 10th International Conference on Cognitive Neuroscience, Bodrum, Turkey, 1 Sep - 5 Sep, 2008. Presentation Type: Oral Presentation Topic: Symposium 2: Cognitive control processes Citation: Phillips N, Goffaux P and Sinai M (2008). The influence of working memory and other cognitive functions on task switching: Evidence from healthy aging and mild cognitive impairment. Conference Abstract: 10th International Conference on Cognitive Neuroscience. doi: 10.3389/conf.neuro.09.2009.01.016 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 26 Nov 2008; Published Online: 26 Nov 2008. * Correspondence: Natalie Phillips, Concordia University, Department of Psychology, Montréal, Canada, Natalie.Phillips@concordia.ca Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Natalie Phillips P. Goffaux M. Sinai Google Natalie Phillips P. Goffaux M. Sinai Google Scholar Natalie Phillips P. Goffaux M. Sinai PubMed Natalie Phillips P. Goffaux M. Sinai Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Unity and diversity of tonic and phasic executive control components in episodic and working memory

The present study aimed to delineate the extent to which unitary executive functions might be shared across the separate domains of episodic and working memory. A mixed blocked/event-related functional magnetic resonance imaging (fMRI) design was employed to assess sustained (tonic control) and transient (phasic control) brain responses arising from incrementing executive demand (source versus item episodic memory – vis-à-vis – two-back versus one-back working memory) using load-dependent activation overlaps as indices of common components. Although an extensive portion of the regional load effects constituted differential control modulations in both sustained and transient responses, commonalities were also found implicating a subset of executive core mechanisms consistent with unitary or domain general control. ‘Unitary’ control modulations were temporally dissociated into (1) shared tonic components involving medial and lateral prefrontal cortex, striatum, cerebellum and superior parietal cortex, assumed to govern enhanced top-down context processing, monitoring and sustained attention throughout task periods and (2) stimulus-synchronous phasic components encompassing posterior intraparietal sulcus, hypothesized to support dynamic shifting of the ‘focus of attention’ among internal representations. Taken together, these results converge with theoretical models advocating both unity and diversity among executive control processes.

Dissociation of sustained attention from central executive functions: local activity and interregional connectivity in the theta range

Human brain oscillatory activity was analysed in the electroencephalographic theta frequency range (4-7 Hz) while subjects executed complex sequential finger movements with varying task difficulty and memory load. Local frontal-midline theta activity was associated with the general level of cognitive demand, with the highest amplitudes in the most demanding condition. Using low-resolution electromagnetic tomography analysis (LORETA), this theta activity was localized in the anterior cingulate gyrus including the cingulate motor area. These results suggest that local theta activity in the anterior cingulate gyrus represents correlates of an attentional system that allocate cognitive resources. In addition, interregional connectivity in the theta frequency range was modulated by memory-related executive functions independently of task difficulty. Connectivity analyses revealed a more distributed long-range network including frontal and parietal cortices during execution of novel compared with well-trained finger movement sequences. Thus, these results are compatible with a model in which theta long-range coupling indicates integration of sensory information into executive control components of complex motor behaviour.

Hypnotizability and spatial attentional functions.

Many theories of hypnotic responding have proposed that differences in hypnotic trait rely on differences in frontal attentional functions. Evidence of hypnotizability-related attentional abilities are, however, very scant. This study was designed to investigate the relationship between hypnotizability and executive control components of attention in the spatial domain. We chose the Attention Network Test that enables to analyze alerting, orienting and executive control functions by measuring reaction times (RTs) to targets cued for different locations in space. According to Posner theory, alerting, orienting and executive control effects were found in both groups. No differences between highly susceptible (Highs) and low susceptible individuals (Lows) on executive control functions were found. However, in Highs alerting was significantly smaller than in Lows and Highs were significantly faster than Lows in the no and central cue conditions. These findings suggest that Highs would be endowed with a basal higher efficiency in achieving and maintaining their readiness to respond to incoming stimuli. This relation between hypnotizability and alerting, is discussed in terms of a possible more efficient noradrenergic activity driven by frontal attentional systems.

Neuroelectric and behavioral indices of interference control during acute cycling

Objective This study examined the effects of in-task, moderate-intensity aerobic exercise on neuroelectric and behavioral indices of interference control, one component of executive control. Methods Forty-one participants completed a V ˙ O 2 max test to determine maximal heart rate (HR). On a separate day, event-related brain potentials and task performance were measured during the counterbalanced conditions of upright cycling at 60% of maximal HR and rest while performing congruent and incongruent trials of a flanker task. Results Exercise resulted in reduced response accuracy for incongruent trials relative to rest; an effect not found for congruent trials. Decreased N1 amplitude was observed during exercise at parietal sites and globally for N2. Exercise also resulted in increased amplitude for the P2 at frontal and central sites, and for the P3 at frontal and lateral sites. Further, longer N2 and P3 latencies were observed during exercise relative to rest. Conclusion These findings suggest that the need to allocate attentional resources toward the large-scale bodily movements inherent in exercise may relate to inefficiency of neural resource allocation, resulting in decreased interference control. Significance These data indicate general and selective exercise-induced decrements in cognitive processing while performing acute aerobic exercise.

Input monitoring and response selection as components of executive control in pro-saccades and anti-saccades

Several studies have shown that anti-saccades, more than pro-saccades, are executed under executive control. It is argued that executive control subsumes a variety of controlled processes. The present study tested whether some of these underlying processes are involved in the execution of anti-saccades. An experiment is reported in which two such processes were parametrically varied, namely input monitoring and response selection. This resulted in four selective interference conditions obtained by factorially combining the degree of input monitoring and the presence of response selection in the interference task. The four tasks were combined with a primary task which required the participants to perform either pro-saccades or anti-saccades. By comparison of performance in these dual-task conditions and performance in single-task conditions, it was shown that anti-saccades, but not pro-saccades, were delayed when the secondary task required input monitoring or response selection. The results are discussed with respect to theoretical attempts to deconstruct the concept of executive control.

Annotation: Deconstructing the attention deficit in fragile X syndrome: a developmental neuropsychological approach.

Fragile X syndrome is one of the world's leading hereditary causes of developmental delay in males. The past decade has witnessed an explosion of research that has begun to unravel the condition at its various levels: from the genetic and brain levels to the cognitive level, and then to the environmental and behavioural levels. Our aim in this review is to attempt to integrate some of the extensive body of knowledge to move the research a step closer to understanding how the dynamics of atypical development can influence the specific cognitive and behavioural end-states frequently observed in children and adolescents with fragile X syndrome. We conducted a review of the current neuropsychological and neuropsychiatric approaches that have attempted to delineate the pattern of 'spared' and 'impaired' functions associated with the phenotype. The profile of findings suggests that fragile X syndrome should not be viewed merely as a catalogue of spared and impaired cognitive functions or modules. Instead, there appears to be a process of almost gradual modularisation whereby cognitive mechanisms become domain specific as a function of development itself (Karmiloff-Smith, 1992). The results of a decade of intense research point towards an early weakness in one or more components of executive control rather than single, static higher-level deficits (e.g., spatial cognition, speech processing). This weakness affects both the development of more complex functions and current performance. The prevailing tendency to interpret developmental disorders in terms of fixed damage to distinct modular functions needs to be reconsidered. We offer this review as an example of an alternative approach, attempting to identify an initial deficit and its consequences for the course of development. Through better definition of the cognitive and behavioural phenotype, in combination with current progress in brain imaging techniques and molecular studies, the next decade should continue to hold exciting promise for fragile X syndrome and other neurodevelopmental disorders.

Aging, expertise and fine motor movement

Age-graded decrements in accuracies and maximum speed of fine motor movements observed in numerous experimental studies have nurtured general factor explanations like the assumption of general age-related slowing of central cognitive processes. This review focuses on two domains of investigation that yielded challenges to general factor models. First, experimental approaches aiming at the decomposition of fine motor skills provide evidence for the dissociability of timing, sequencing, and executive control components that show differential rather than general age-related changes. Second, studies on cognitive-motor expertise demonstrate that age-related changes in critical skill components depend on individuals' time investments into specific practice activities. It is argued that the process dissociations observed at the behavioral level in developmental (i.e. age and expertise) studies reflect individuals' long-term adaptations to internal and external performance constraints. The outcomes of these adaptation processes are stable interindividual differences in component processes.

Arithmetic fact retrieval and working memory in schizophrenia

Despite its importance in every-day life and vocational rehabilitation, arithmetic ability has rarely been investigated in schizophrenic patients. Those few studies reporting arithmetic deficits in schizophrenia, however, administered complex calculation tasks which drew not only on arithmetic abilities, but also on working memory resources known to be impaired in schizophrenia. In the present study, arithmetic abilities and working memory functions were investigated in schizophrenic patients ( n=24) and healthy control subjects ( n=24). Arithmetic fact retrieval was assessed in single-digit multiplication and corresponding division problems using a result verification task which minimized working memory demands. Problem size and the disparity of the proposed result were manipulated. The storage component of working memory was tested with a digit span forward task and the executive control component with a digit span backward as well as with verbal fluency tasks. Schizophrenic patients performed worse than controls only in the executive tasks. Digit span forward was preserved. In the arithmetic tasks, groups did not differ from each other, and a similar pattern of task manipulations was obtained. Hence, despite the executive control deficit retrieval of arithmetic facts is preserved in schizophrenia. Moreover, the same underlying cognitive processes as in control subjects are involved.

Working memory and executive control.

A major problem in analysing the executive processes that seem to depend upon the prefrontal cortex stems from the absence of a well developed cognitive model of such processes. It is suggested that the central executive component of an earlier model of working memory might provide a suitable framework for such an analysis. The approach is illustrated using one proposed component of executive control, namely the capacity to combine two concurrent tasks. The application of the approach to patients suffering from Alzheimer's disease, and patients with acquired brain damage is discussed. Finally, a study is described in which the dual task performance of patients with known frontal lesions is shown to be associated with observed behavioural problems. The paper concludes with the discussion of the prospects for extending the approach to include a range of other executive processes, and to the way in which such an analysis may subsequently lead to a more integrated model of the central executive, and a better understanding of its relationship to the prefrontal cortex.

Switching attention between tasks: Exploration of the components of executive control and their development with training

Top down processes guided by attention and intention, have been recognized to be important determinants, and necessary complements in the formulation and guidance of skilled performance. The present paper summarizes the results of four experiments conducted to investigate the control operations and the cost involved in switching attention between task dimensions and attention strategies. Subjects were asked to switch between judging the value of digits, or the number of digit elements, in rows of digits presented on the screen. Alternatively they performed the task, switching between speed or accuracy emphasis. The experimental results provide strong evidence for the work of executive processes which operate as attention strategies and policy regulators. They are executed top down, in the service of intentions and basic attention policies, but depend on the existence of task representations, including the “so called” automatic performance units. Executive processes are shown to have sizable operation costs, over and beyond those imposed by the direct processing and response demands of the performed tasks. These costs are reduced with specific training focusing on the improvement of control functions.