Jan R Wiersema

Ghent University, Gand, Flanders, Belgium

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Publications (39)117.68 Total impact

  • Inez Buyck, Jan R Wiersema
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    ABSTRACT: This study investigated the stability and state-related characteristics of electroencephalographic (EEG) deviances in attention-deficit/hyperactivity disorder (ADHD). Three minutes resting EEG with eyes closed and eyes open were compared between 21 children with ADHD and 29 typically developing children. Across resting conditions, children with ADHD exhibited divergent topographic distribution for theta, alpha and beta power compared to typically developing children. In addition, less alpha and theta suppression to eye opening was found in children with ADHD, but only in those without comorbid ODD/CD. Findings of the present study refer to a consistent divergence in topographic distribution in ADHD across resting state conditions, yet demonstrate that state-related factors and comorbidity may also contribute to resting EEG deviances in ADHD. The state-related findings are in accord with several theoretical accounts emphasizing the role of contextual and state factors defining deficits in ADHD.
    Research in developmental disabilities. 08/2014; 35(12):3217-3225.
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    ABSTRACT: This study adds to knowledge on somatisation in adolescents by exploring its relation with parenting behaviour and the mediating/moderating role of physiological responses in adolescents to parenting behaviour.
    International journal of psychophysiology: official journal of the International Organization of Psychophysiology 05/2014; · 3.05 Impact Factor
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    ABSTRACT: The default mode network (DMN) is the core brain system supporting internally oriented cognition. The ability to attenuate the DMN when switching to externally oriented processing is a prerequisite for effective performance and adaptive self-regulation. Right anterior insula (rAI), a core hub of the salience network (SN), has been proposed to control the switching from DMN to task-relevant brain networks. Little is currently known about the extent of anticipatory processes subserved by DMN and SN during switching. We investigated anticipatory DMN and SN modulation using a novel cued-switching task of between-state (rest-to-task/task-to-rest) and within-state (task-to-task) transitions. Twenty healthy adults performed the task implemented in an event-related functional magnetic resonance imaging (fMRI) design. Increases in activity were observed in the DMN regions in response to cues signalling upcoming rest. DMN attenuation was observed for rest-to-task switch cues. Obversely, DMN was up-regulated by task-to-rest cues. The strongest rAI response was observed to rest-to-task switch cues. Task-to-task switch cues elicited smaller rAI activation, whereas no significant rAI activation occurred for task-to-rest switches. Our data provide the first evidence that DMN modulation occurs rapidly and can be elicited by short duration cues signalling rest- and task-related state switches. The role of rAI appears to be limited to certain switch types - those implicating transition from a resting state and to tasks involving active cognitive engagement.
    NeuroImage 05/2014; · 6.25 Impact Factor
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    ABSTRACT: Investigating the underlying neural mechanisms of autism spectrum disorder (ASD) has recently been influenced by the discovery of mirror neurons. These neurons, active during both observation and execution of actions, are thought to play a crucial role in imitation and other social-communicative skills that are often impaired in ASD. In the current electroencephalographic study, we investigated mu suppression, indicating neural mirroring in children with ASD between the ages of 24 and 48 months and age-matched typically developing children, during observation of goal-directed actions and non-goal-directed mimicked hand movements, as well as during action execution. Results revealed no significant group differences with significant central mu suppression in the ASD children and control children during both execution and observation of goal-directed actions and during observation of hand movements. Furthermore, no significant correlations between mu suppression on one hand and quality of imitation, age, and social communication questionnaire scores on the other hand were found. These findings challenge the "broken mirror" hypothesis of ASD, suggesting that impaired neural mirroring is not a distinctive feature of ASD. Autism Res 2014, ●●: ●●- ●●. © 2014 International Society for Autism Research, Wiley Periodicals, Inc.
    Autism Research 02/2014; · 3.99 Impact Factor
  • Inez Buyck, Jan Roelf Wiersema
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    ABSTRACT: This study investigated EEG activity and its developmental course in ADHD throughout the lifespan, as well as the accuracy of EEG parameters in distinguishing ADHD patients from typically developing individuals. Three minutes eyes closed resting EEG was compared between 62 individuals with ADHD (36 children, 26 adults) and 55 typically developing individuals (30 children, 25 adults). EEG activity and maturation did not differ between individuals with ADHD and typically developing individuals. However, despite comparable developmental course between clinical groups, persistent elevated theta/beta ratio and reduced relative beta power were observed in the ADHD inattentive subtype compared to the ADHD combined subtype and controls across the lifespan. Therefore, a maturational deviation rather than a maturational delay may underlie a subgroup of ADHD. EEG based classification failed for ADHD but proved successful for age. These findings emphasize heterogeneity in ADHD throughout the lifespan and question clinical utility of conventional EEG approaches for diagnostic purposes in ADHD.
    Psychiatry Research. 01/2014;
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    ABSTRACT: Objective The present study investigates whether either adolescents' psychological distress and/or perceived parenting predicted the occurrence of NSSI. Furthermore, the consequences of NSSI are examined in a three-wave longitudinal study. Design The sample at time 1 (age 12) consisted of 1396 adolescent reports and 1438 parent reports. At time 2 (age 13), 827 adolescent reports and 936 parent reports were obtained. Time 3 (age 14) included 754 adolescent reports and 790 parent reports. Psychological distress of adolescents was measured using the Strengths and Difficulties Questionnaire. Perceived parenting behaviors were examined by the Parental Behavior Scale and the Psychological Control Scale. Results A total of 10% of the adolescents engaged in NSSI at least once before age 15. Higher psychological distress of adolescents at time 1 was associated with the presence of NSSI at time 2 or 3. The association between psychological distress at time 1 and perception of decreased parental rule setting at time 3 was mediated by the presence of NSSI at time 2. Conclusions The present study showed that psychological distress at age 12 predicts NSSI over time and that parental awareness of NSSI changes the perception of parenting behaviors.
    Journal of Adolescence. 01/2014; 37(6):817–826.
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    ABSTRACT: This study examines the influence of a button response task on the event-related potential (ERP) in a semantic priming experiment. Of particular interest is the N400 component. In many semantic priming studies, subjects are asked to respond to a stimulus as fast and accurately as possible by pressing a button. Response time (RT) is recorded in parallel with an electroencephalogram (EEG) for ERP analysis. In this case, the response occurs in the time window used for ERP analysis and response-related components may overlap with stimulus-locked ones such as the N400. This has led to a recommendation against such a design, although the issue has not been explored in depth. Since studies keep being published that disregard this issue, a more detailed examination of influence of response-related potentials on the ERP is needed. Two experiments were performed in which subjects pressed one of two buttons with their dominant hand in response to word-pairs with varying association strength (AS), indicating a personal judgement of association between the two words. In the first experiment, subjects were instructed to respond as fast and accurately as possible. In the second experiment, subjects delayed their button response to enforce a one second interval between the onset of the target word and the button response. Results show that in the first experiment a P3 component and motor-related potentials (MRPs) overlap with the N400 component, which can cause a misinterpretation of the latter. In order to study the N400 component, the button response should be delayed to avoid contamination of the ERP with response-related components.
    PLoS ONE 01/2014; 9(2):e87650. · 3.53 Impact Factor
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    ABSTRACT: Executive attention and its relationship with effortful control (EC) were investigated in children with ADHD (n = 24), autism spectrum disorder (ASD; n = 20), and controls (n = 21). Executive attention measures included flanker-performance and event-related potentials (N2, P3, and ERN). EC was assessed using questionnaires. Only the ERN was found to be robustly related to EC across groups. N2 did not differ between groups and only children with ADHD + ODD showed diminished executive attention as expressed in RT and P3. In ADHD, monitoring of incorrect (ERN) and correct (CRN) responses was diminished. Overall, the link between EC and executive attention was less strong as expected and varied depending on group and measure considered. All groups were able to detect conflict (N2) and all but ADHD + ODD were able to allocate extra attention in order to respond correctly (P3). Findings indicate a general reduced response monitoring in ADHD.
    Biological psychology 01/2014; · 4.36 Impact Factor
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    ABSTRACT: Introduction This study adds to knowledge on somatisation in adolescents by exploring its relation with parenting behaviour and the mediating/moderating role of physiological responses in adolescents to parenting behaviour. Method Eighteen adolescents with high and eighteen adolescents with low somatisation scores and their mothers completed a discussion task, from which observed parenting behaviour scores were derived. Skin conductance in adolescents was measured before and during the discussion. Results For adolescents with high levels of physiological responses, unadaptive parenting was related to a higher chance of high somatisation scores. For low physiologically responsive adolescents, the relation between parenting behaviour and somatisation was not significant. Conclusion Parenting behaviour is not univocally related to somatisation in adolescents, but the association depends on physiological responses in adolescents.
    International Journal of Psychophysiology. 01/2014;
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    ABSTRACT: Attention Deficit/Hyperactivity Disorder (ADHD) is a pathophysiologically complex and heterogeneous condition with both cognitive and motivational components. We propose a novel computational hypothesis of motivational deficits in ADHD, drawing together recent evidence on the role of anterior cingulate cortex (ACC) and associated mesolimbic dopamine circuits in both reinforcement learning and ADHD. Based on findings of dopamine dysregulation and ACC involvement in ADHD we simulated a lesion in a previously validated computational model of ACC (Reward Value and Prediction Model, RVPM). We explored the effects of the lesion on the processing of reinforcement signals. We tested specific behavioral predictions about the profile of reinforcement-related deficits in ADHD in three experimental contexts; probability tracking task, partial and continuous reward schedules, and immediate versus delayed rewards. In addition, predictions were made at the neurophysiological level. Behavioral and neurophysiological predictions from the RVPM-based lesion-model of motivational dysfunction in ADHD were confirmed by data from previously published studies. RVPM represents a promising model of ADHD reinforcement learning suggesting that ACC dysregulation might play a role in the pathogenesis of motivational deficits in ADHD. However, more behavioral and neurophysiological studies are required to test core predictions of the model. In addition, the interaction with different brain networks underpinning other aspects of ADHD neuropathology (i.e., executive function) needs to be better understood.
    Neural networks: the official journal of the International Neural Network Society 05/2013; 46C:199-209. · 1.88 Impact Factor
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    ABSTRACT: OBJECTIVE: Previous infant studies investigated neural mirroring during the observation of live or video actions. However, both methods have their (dis)advantages and studies using one of these methods are not always directly comparable. Therefore, the present study directly compared neural mirroring activity in a video setting with a live setting in infants between 18 and 36months old. METHODS: Central mu rhythm suppression was measured through EEG recordings during the observation and imitation of the same goal-directed and mimicked actions presented either on video or live. RESULTS: Results revealed significant mu suppression during action imitation in both settings but stronger mu suppression was observed in the live setting during this condition. Significant mu suppression during the observation of goal-directed actions and mimicked actions was only observed in the live setting. CONCLUSION: This study revealed a different influence of video and live actions on neural mirroring activity in infants. SIGNIFICANCE: It is recommended to use live actions to investigate neural mirroring in young children.
    Clinical neurophysiology: official journal of the International Federation of Clinical Neurophysiology 05/2013; · 3.12 Impact Factor
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    ABSTRACT: Objective: The preference for sooner smaller over larger later rewards is a prominent manifestation of impulsivity in ADHD. According to the State Regulation Deficit (SRD) model, this impulsive choice is the result of impaired regulation of arousal level and can be alleviated by adding environmental stimulation to increase levels of arousal. Method: To test this prediction, we studied the effects of adding background "pink noise" on impulsive choice using a classical and new adjusting choice delay task in a sample of 25 children with ADHD and 28 controls. Results: Children with ADHD made more impulsive choices than controls. Adding noise did not reduce impulsive choice in ADHD. Conclusion: The findings add to the existing evidence on impulsive choice in ADHD, but no evidence is found for the SRD model's explanation of this behavioral style. Alternative explanations for impulsive choice in ADHD are discussed. (J. of Att. Dis. 2013; XX(X) 1-XX).
    Journal of Attention Disorders 03/2013; · 2.16 Impact Factor
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    ABSTRACT: Since their discovery in the early 1990s, mirror neurons have been proposed to be related to many social-communicative abilities, such as imitation. However, research into the early manifestations of the putative neural mirroring system and its role in early social development is still inconclusive. In the current EEG study, mu suppression, generally thought to reflect activity in neural mirroring systems was investigated in 18- to 30-month-olds during the observation of object manipulations as well as mimicked actions. EEG power data recorded from frontal, central, and parietal electrodes were analysed. As predicted, based on previous research, mu wave suppression was found over central electrodes during action observation and execution. In addition, a similar suppression was found during the observation of intransitive, mimicked hand movements. To a lesser extent, the results also showed mu suppression at parietal electrode sites, over all three conditions. Mu wave suppression during the observation of hand movements and during the execution of actions was significantly correlated with quality of imitation, but not with age or language level.
    Developmental Science 03/2013; 16(2):173-85. · 3.89 Impact Factor
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    ABSTRACT: Objective: Attention-deficit/hyperactivity disorder (ADHD) is associated with performance deficits across a broad range of tasks. Although individual tasks are designed to tap specific cognitive functions (e.g., memory, inhibition, planning, etc.), these deficits could also reflect general effects related to either inefficient or impulsive information processing or both. These two components cannot be isolated from each other on the basis of classical analysis in which mean reaction time (RT) and mean accuracy are handled separately. Method: Seventy children with a diagnosis of combined type ADHD and 50 healthy controls (between 6 and 17 years) performed two tasks: a simple two-choice RT (2-CRT) task and a conflict control task (CCT) that required higher levels of executive control. RT and errors were analyzed using the Ratcliff diffusion model, which divides decisional time into separate estimates of information processing efficiency (called "drift rate") and speed-accuracy tradeoff (SATO, called "boundary"). The model also provides an estimate of general nondecisional time. Results: Results were the same for both tasks independent of executive load. ADHD was associated with lower drift rate and less nondecisional time. The groups did not differ in terms of boundary parameter estimates. Conclusion: RT and accuracy performance in ADHD appears to reflect inefficient rather than impulsive information processing, an effect independent of executive function load. The results are consistent with models in which basic information processing deficits make an important contribution to the ADHD cognitive phenotype. (PsycINFO Database Record (c) 2013 APA, all rights reserved).
    Neuropsychology 03/2013; 27(2):193-200. · 3.58 Impact Factor
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    ABSTRACT: Objective: The present study investigated differences in attentional networks in typically developing (TD) boys and boys with ADHD or autism spectrum disorder (ASD). In addition, we investigated the relationship between networks and the relationship with effortful control (EC). Method: An Attention Network Test was used to assess alerting, orienting, and executive attention in 25 TD boys, 25 boys with ADHD, and 25 boys with ASD. Results: In the absence of warning signals, boys with ADHD performed poorer than other children. In all groups, the orienting and executive control networks and the alerting and orienting networks interacted. Executive attention and EC were unrelated. Conclusion: Results provided evidence of impaired tonic alertness in ADHD and support the idea of functional integration of attentional networks. Finally, findings suggest that the link between EC reports and indices of neural systems involved in the effortful regulation of behavior may not be as unambiguous as previously thought. (J. of Att. Dis. 2013; XX(X) 1-XX).
    Journal of Attention Disorders 02/2013; · 2.16 Impact Factor
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    ABSTRACT: Objective: Cognitive and motivational factors differentially affect individuals with mental health problems such as ADHD. Here we introduce a new task to disentangle the relative contribution of inhibitory control and reward anticipation on task performance in children with ADHD and/or autism spectrum disorders (ASD). Method: Typically developing children, children with ADHD, ASD, or both disorders worked during separate sessions for monetary or social rewards in go/no-go tasks with varying inhibitory load levels. Participants also completed a monetary temporal discounting (TD) task. Results: As predicted, task performance was sensitive to both the effects of anticipated reward amount and inhibitory load. Reward amount had different effects depending on inhibitory load level. TD correlated with inhibitory control in the ADHD group. Conclusion: The integration of the monetary incentive delay and go/no-go paradigms was successful. Surprisingly, there was no evidence of inhibitory control deficits or altered reward anticipation in the clinical groups. (J. of Att. Dis. 2013; XX(X) 1-XX).
    Journal of Attention Disorders 02/2013; · 2.16 Impact Factor
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    ABSTRACT: This study explored direct and indirect associations between adolescents' somatization, parenting stress, and three parenting dimensions (warmth, psychological control, and harsh punishment). First, the associations were explored cross-sectionally. Second, significant cross-sectional links were further examined longitudinally in order to decide upon temporality. A total of 1499 adolescents and one of their parents (mostly the mother) agreed to participate. Questionnaires were administered when the child was respectively 12-13 (T1), 13-14 (T2), and 14-15 (T3) years old. Adolescents reported on their somatization, parents on their parenting behavior and parenting stress. Cross-sectionally, indirect links were found between all parenting dimensions and adolescents' somatization, through parenting stress. Longitudinal examination revealed two key aspects. First, parenting stress significantly predicted somatization. Higher T1 parenting stress was predictive for higher T2 and T3 somatization. When controlled for T1 parenting stress, higher T2 parenting stress (or in other words increased parenting stress at T2) was predictive for lower T3 somatization. Second, parenting stress was found to significantly predict parenting behaviors. Higher T1 parenting stress was predictive for higher T2 and T3 harsh punishment but increased parenting stress at T2 was predictive for lower harsh punishment one year later. Higher T1 parenting stress significantly predicted higher T2 psychological control. Clinicians should be aware that parenting stress may be a risk factor for the development of somatization in early adolescence. However, in later adolescence, increased parenting stress might be protective.
    The International Journal of Psychiatry in Medicine 01/2013; 46(3):243-70. · 1.15 Impact Factor
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    ABSTRACT: Interpreting others' actions is essential for understanding the intentions and goals in social interactions. Activity in the motor cortex is evoked when we see another person performing actions, which can also be influenced by the intentions and context of the observed action. No study has directly explored the influence of reward and punishment on motor cortex activity when observing others' actions, which is likely to have substantial relevance in different social contexts. In this experiment, EEG was recorded while participants watched movie clips of a person performing actions that led to a monetary reward, loss or no change for the observer. Using the EEG mu rhythm as an index of motor resonance, our results demonstrate that observation of rewarding actions produce significantly greater motor cortex activity than punishing or neutral actions, with punishing actions producing greater activity than neutral ones. In addition, the dynamic change in the mu rhythm over sensorimotor cortex is modulated by reward and punishment, with punishing actions producing a prolonged suppression. These findings demonstrate that the associated reward value of an observed action may be crucial in determining the strength of the representation of the action in the observer's brain. Consequently, reward and punishment is likely to drive observational learning through changes in the action observation network, and may also influence how we interpret, understand, engage in and empathize with others' actions in social interaction.
    Neuropsychologia 11/2012; · 3.48 Impact Factor
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    ABSTRACT: BACKGROUND: According to the state regulation deficit model, event rate (ER) is an important determinant of performance of children with attention-deficit/hyperactivity disorder (ADHD). Fast ER is predicted to create overactivation and produce errors of commission, whereas slow ER is thought to create underactivation marked by slow and variable reaction times (RT) and errors of omission. METHODS: To test these predictions, we conducted a systematic search of the literature to identify all reports of comparisons of ADHD and control individuals' performance on Go/No-Go tasks published between 2000 and 2011. In one analysis, we included all trials with at least two event rates and calculated the difference between ER conditions. In a second analysis, we used metaregression to test for the moderating role of ER on ADHD versus control differences seen across Go/No-Go studies. RESULTS: There was a significant and disproportionate slowing of reaction time in ADHD relative to controls on trials with slow event rates in both meta-analyses. For commission errors, the effect sizes were larger on trials with fast event rates. No ER effects were seen for RT variability. There were also general effects of ADHD on performance for all variables that persisted after effects of ER were taken into account. CONCLUSIONS: The results provide support for the state regulation deficit model of ADHD by showing the differential effects of fast and slow ER. The lack of an effect of ER on RT variability suggests that this behavioral characteristic may not be a marker of cognitive energetic effects in ADHD.
    Biological psychiatry 10/2012; · 8.93 Impact Factor
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    ABSTRACT: Activity in the motor cortex is induced when we watch others performing actions (Gallese et al., 1996), and can also be influenced by the intentions and context of the observed action (Iacoboni et al., 2005; Perry et al., 2010). The effect of reward and punishment on motor resonance has not yet been directly explored, though it is likely that different social contexts will be associated with different degrees of reward and punishment. EEG was recorded from 17 healthy right-handed females while they passively observed video clips of a person performing actions that led to a monetary reward, loss (i.e. punishment) or no change for the observer. The study compared the EEG mu rhythm suppression between conditions and showed that it was modulated by the motivational value of the observed action, with activity being the largest for rewarding actions and the least for neutral actions. We also show temporal dynamic changes in the mu rhythm power of these effects, with punishing actions producing delayed and prolonged mu suppression. This provides evidence for reward-related modulation of motor cortex activity during action observation. Our findings suggest that future studies investigating the neural activity related to the observation of others' actions may need to consider the effect of the reward (and punishment) associations made with the observed actions when comparing across conditions. The presence of reward-related modulation in motor resonance may also help to explain some previous inconsistent findings comparing mu rhythm activity in different clinical groups such as autism spectrum disorders (Oberman et al., 2012) and in schizophrenia (Singh et al., 2011). The reward and punishment associated with the actions we see in our social environment is likely to drive observational learning and may also influence how we interpret, understand, engage in and empathize with others’ actions in social interaction.
    Frontiers in Human Neuroscience 09/2012; · 2.91 Impact Factor

Publication Stats

482 Citations
117.68 Total Impact Points

Institutions

  • 2005–2014
    • Ghent University
      • Department of Experimental Clinical and Health Psychology
      Gand, Flanders, Belgium
  • 2009
    • University of Southampton
      • Department of Psychology
      Southampton, ENG, United Kingdom
    • University of Groningen
      • Department of Psychology
      Groningen, Province of Groningen, Netherlands