Publications by authors named "Dirk Geurts"

Objective: Parkinson's disease (PD) resting tremor is thought to be initiated in the basal ganglia and amplified in the cerebello-thalamo-cortical circuit. Because stress worsens tremor, the noradrenergic system may play a role in amplifying tremor. We tested if and how propranolol, a non-selective beta-adrenergic receptor antagonist, reduces PD tremor and whether or not this effect is specific to stressful conditions.

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Background: Major Depressive disorder (MDD) and Attention Deficit Hyperactivity Disorder (ADHD) are prevalent mental disorders that often co-occur. There is overlap in symptomatology between MDD and ADHD that complicates diagnostics and treatment selection. Hence, to aid diagnostics of single and comorbid disorders, we aimed to examine the discriminative power of common symptom measures and cognitive dysfunction to differentiate between participants diagnosed with MDD, ADHD, ADHD and comorbid MDD and without a mental disorder.

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Background: Stress-related disorders are a growing public health concern. While stress is a natural and adaptive process, chronic exposure to stressors can lead to dysregulation and take a cumulative toll on physical and mental well-being. One approach to coping with stress and building resilience is through Mindfulness-Based Stress Reduction (MBSR).

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Interaction between Pavlovian and instrumental control systems is key for adaptive motivated behavior, but also plays an important role in various neuropsychiatric disorders, including depression, addiction, and anxiety. Here, we employed the flouorodopa positron emission tomography ([¹⁸F]-DOPA PET) in healthy participants ( = 100) to assess whether dopamine synthesis capacity (K), specifically in the ventral striatum, accounts for individual variation in Pavlovian-to-instrumental transfer (PIT). Surprisingly, this was not the case.

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Background: Violent offenders with psychopathic tendencies are characterized by instrumental, i.e., planned, callous, and unemotional (aggressive) behavior and have been shown to exhibit abnormal aversive processing.

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Borderline personality disorder (BPD) is a prevalent, devastating, and heterogeneous psychiatric disorder. Treatment success is highly variable within this patient group. A cognitive neuroscientific approach to BPD might contribute to precision psychiatry by identifying neurocognitive factors that predict who will benefit from a specific treatment.

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Background: Preliminary evidence suggests that Mindfulness-Based Cognitive Therapy (MBCT) is a promising treatment for bipolar disorder (BD). A proposed working mechanism of MBCT in attenuating depressive symptoms is reducing depressive rumination. The primary aim of this study was to investigate the effect of MBCT on self-reported trait depressive rumination and an experimental state measure of negative intrusive thoughts in BD patients.

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Background: Control over the tendency to make or withhold responses guided by contextual Pavlovian information plays a key role in understanding impulsivity and hyperactivity. Here we set out to assess (1) the understudied relation between contextual Pavlovian inhibitory control and hyperactivity/impulsivity in adults with ADHD and (2) whether this inhibition can be enhanced by mindfulness based cognitive therapy (MBCT).

Methods: Within the framework of a randomized controlled trial 50 Adult ADHD patients were assessed before and after 8 weeks of treatment as usual (TAU) with ( = 24) or without ( = 26) MBCT.

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Repetitive negative thinking (RNT) captures an important transdiagnostic factor that predisposes to a maladaptive stress response and contributes to diverse psychiatric disorders. Although RNT can best be seen as a continuous symptom dimension that cuts across boundaries from health to various psychiatric disorders, the neural mechanisms underlying RNT have almost exclusively been studied in health and stress-related disorders, such as depression and anxiety disorders. We set out to study RNT from a large-scale brain network perspective in a diverse population consisting of healthy subjects and patients with a broader range of psychiatric disorders.

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Negative self-referential processing has fruitfully been studied in unipolar depressed patients, but remarkably less in patients with bipolar disorder (BD). This exploratory study examines the relation between task-based self-referential processing and depressive symptoms in BD and their possible importance to the working mechanism of mindfulness-based cognitive therapy (MBCT) for BD. The study population consisted of a subsample of patients with BD ( = 49) participating in an RCT of MBCT for BD, who were assigned to MBCT + TAU ( = 23) or treatment as usual (TAU) ( = 26).

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Background: It is widely acknowledged that comorbidity between psychiatric disorders is common. Shared and diverse underpinnings of psychiatric disorders cannot be systematically understood based on symptom-based categories of mental disorders, which map poorly onto pathophysiological mechanisms. In the Measuring Integrated Novel Dimensions in Neurodevelopmental and Stress-Related Mental Disorders (MIND-SET) study, we make use of current concepts of comorbidity that transcend the current diagnostic categories.

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Rationale: Brain catecholamines have long been implicated in reinforcement learning, exemplified by catecholamine drug and genetic effects on probabilistic reversal learning. However, the mechanisms underlying such effects are unclear.

Objectives And Methods: Here we investigated effects of an acute catecholamine challenge with methylphenidate (20 mg, oral) on a novel probabilistic reversal learning paradigm in a within-subject, double-blind randomised design.

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Background: Over the past two decades there has been a growing number of randomized clinical trials supporting the efficacy of mindfulness-based cognitive therapy (MBCT) in the treatment of several psychiatric disorders. Since evidence for its effectiveness in routine clinical practice is lagging behind, we aimed to examine adherence, outcome and predictors of MBCT in a well-characterized, heterogeneous outpatient population in routine clinical practice.

Methods: Data were collected from a naturalistic uncontrolled cohort of 998 patients formally diagnosed with mainly depression, anxiety disorders, personality disorders, somatoform disorders and/or ADHD.

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Background: Meta-analyses show efficacy of mindfulness-based cognitive therapy (MBCT) in terms of relapse prevention and depressive symptom reduction in patients with major depressive disorder (MDD). However, most studies have been conducted in controlled research settings.

Aims: We aimed to investigate the effectiveness of MBCT in patients with MDD presenting in real-world clinical practice.

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Deficits in instrumental, goal-directed control, combined with the influence of drug-associated Pavlovian-conditioned stimuli, are thought to influence the development and maintenance of addiction. However, direct evidence has mainly come from animal studies. We sought to establish whether alcohol use disorder (AUD) is characterized by behavioral or neurobiological deficits in (i) the integration of Pavlovian and instrumental values and (ii) goal-directed control; and (iii) whether duration or severity of AUD is associated with such deficits.

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Mindfulness-based cognitive therapy (MBCT) has been demonstrated to be effective in adults with ADHD. The aim of the current study was to examine its possible working mechanisms. In the context of an randomized controlled trial (RCT), MBCT + TAU (treatment as usual) ( = 43) versus TAU ( = 51), we used mediation analyses to examine whether reduction of clinician-rated ADHD symptoms and improvement of positive mental health at 6-month follow-up had been mediated by change in mindfulness skills, self-compassion, and executive functioning over the course of MBCT.

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The remarkable expedience of human learning is thought to be underpinned by meta-learning, whereby slow accumulative learning processes are rapidly adjusted to the current learning environment. To date, the neurobiological implementation of meta-learning remains unclear. A burgeoning literature argues for an important role for the catecholamines dopamine and noradrenaline in meta-learning.

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The catecholamines have long been associated with cognitive control and value-based decision-making. More recently, we proposed that the catecholamines might modulate value-based decision-making about whether or not to engage in cognitive control. We test this hypothesis by assessing effects of a catecholamine challenge in a large sample of young, healthy adults (n = 100) on the avoidance of a cognitively demanding control process: task switching.

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Dopamine has been associated with risky decision-making, as well as with pathological gambling, a behavioral addiction characterized by excessive risk-taking behavior. However, the specific mechanisms through which dopamine might act to foster risk-taking and pathological gambling remain elusive. Here we test the hypothesis that this might be achieved, in part, via modulation of subjective probability weighting during decision making.

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Background: Chronic fatigue syndrome (CFS) is characterized by disabling fatigue, which is suggested to be maintained by dysfunctional beliefs. Fatigue and its maintenance are recently conceptualized as arising from abnormally precise expectations about bodily inputs and from beliefs of diminished control over bodily states, respectively. This study used functional neuroimaging to identify the neural correlates of fatigue and its maintenance by beliefs during a physical effort task.

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Catecholamines modulate the impact of motivational cues on action. Such motivational biases have been proposed to reflect cue-based, 'Pavlovian' effects. Here, we assess whether motivational biases may also arise from asymmetrical instrumental of active and passive responses following reward and punishment outcomes.

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Background: Chronic fatigue syndrome (CFS) is characterized by severe fatigue persisting for ≥6 months and leading to considerable impairment in daily functioning. Neuroimaging studies of patients with CFS have revealed alterations in prefrontal brain morphology. However, it remains to be determined whether these alterations are specific for fatigue or whether they relate to other common CFS symptoms (e.

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Criminal behaviour poses a big challenge for society. A thorough understanding of the neurobiological mechanisms underlying criminality could optimize its prevention and management. Specifically,elucidating the neural mechanisms underpinning reward expectation might be pivotal to understanding criminal behaviour.

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Near-misses in gambling games are losing events that come close to a win. Near-misses were previously shown to recruit reward-related brain regions including the ventral striatum, and to invigorate gambling behavior, supposedly by fostering an illusion of control. Given that pathological gamblers are particularly vulnerable to such cognitive illusions, their persistent gambling behavior might result from an amplified striatal sensitivity to near-misses.

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Background: Chronic fatigue syndrome (CFS) is characterized by profound and disabling fatigue with no known somatic explanation. Cognitive behavioral therapy (CBT) has proven to be a successful intervention leading to a reduction in fatigue and disability. Based on previous neuroimaging findings, it has been suggested that central neural mechanisms may underlie CFS symptoms and play a role in the change brought on by CBT.

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