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Author: Norbert Kathmann (112)


Dec
2017

Brain imaging studies of structural abnormalities in OCD have yielded inconsistent results, partly because of limited statistical power, clinical heterogeneity, and methodological differences. The authors conducted meta- and mega-analyses comprising the largest study of cortical morphometry in OCD ever undertaken.
T-weighted MRI scans of 1,905 OCD patients and 1,760 healthy controls from 27 sites worldwide were processed locally using FreeSurfer to assess cortical thickness and surface area.

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Dec
1969

Previous research in patients with obsessive-compulsive disorder (OCD) has indicated performance decrements in working memory (WM) and response inhibition. However, underlying neural mechanisms of WM deficits are not well understood to date, and empirical evidence for a proposed conceptual link to inhibition deficits is missing. We investigated WM performance in a numeric n-back task with four WM load conditions during functional Magnetic Resonance Imaging (fMRI) in 51 patients with OCD and 49 healthy control participants who were matched for age, sex, and education.

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Jan
2018

Childhood maltreatment (CM) confers deleterious long-term consequences, and growing evidence suggests some of these effects may be transmitted across generations. We examined the intergenerational effect of maternal CM exposure on child brain structure and also addressed the hypothesis that this effect may start during the child's intrauterine period of life.
A prospective longitudinal study was conducted in a clinical convenience sample of 80 mother-child dyads.

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Oct
2017

The critical importance of thyroid hormones for fetal development is well established. The developing fetus is dependent on the mother for adequate thyroid hormone supply, and maternal thyroid dysfunction in pregnancy may result in suboptimal fetal development. Because exposure to childhood maltreatment (CM) has been associated with thyroid dysfunction in the non-pregnant state, we sought to test the hypothesis that exposure to CM may represent a risk factor for the development of maternal hypothyroidism in pregnancy.

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Dec
2016

Suspecting significance behind ordinary events is a common feature in psychosis and it is assumed to occur due to aberrant salience attribution. The Salience Attribution Test (SAT; Roiser et al., 2009) measures aberrant salience as a bias towards one out of two equally reinforced cue features as opposed to adaptive salience towards features indicating high reinforcement.

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Nov
2017

Patients with obsessive-compulsive disorder (OCD) experience abnormally high levels of uncertainty, and unpredictability is evaluated negatively and not well tolerated. The current study examined neural correlates of attentional processing in response to experimentally induced uncertainty in OCD.
Twenty-four OCD patients and 24 healthy controls performed a task where neutral and negative pictures were preceded by a cue, either being predictive (certain condition) or nonpredictive (uncertain condition) of subsequent picture valence.

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Aug
2017

Frontal electroencephalographic alpha asymmetry as an indicator of trait approach and trait inhibition systems has previously been studied in individuals with obsessive-compulsive disorder (OCD) with mixed results. We explored frontal alpha asymmetry as a possible risk factor in OCD by investigating a large sample of OCD patients (n = 113), healthy control participants (n = 113), and unaffected 1st-degree relatives of OCD patients (n = 37). Additionally, the relationship between OCD symptom dimensions and frontal alpha asymmetry was explored.

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Sep
2017

Recent evidence indicates that patients with obsessive-compulsive disorder (OCD) as well as their unaffected first-degree relatives show deficits in the volitional control of saccades, suggesting that volitional saccade performance may constitute an endophenotype of OCD. Here, we aimed to replicate and extend these findings in a large, independent sample. One hundred and fifteen patients with OCD, 103 healthy comparison subjects without a family history of OCD, and 31 unaffected first-degree relatives of OCD patients were examined using structured clinical interviews and performed a volitional saccade task as well as a prosaccade task.

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Feb
2017

Hyperactive error-related brain activity has been found in individuals with obsessive-compulsive disorder (OCD), generalized and social anxiety as well as depression and has been proposed as a transdiagnostic marker. The specific phenotype to which it is related is still debated and anxious apprehension, threat sensitivity and checking have been proposed as promising candidates. To validate the idea that hyperactive performance monitoring is shared by anxiety and anxiety-related disorders and to refine our knowledge about its specificity, data from further anxiety and anxiety-related disorders are required.

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Dec
1969

Emotional processing is influenced by top-down processes such as reappraisal of emotion-inducing events. Besides one's own stimulus appraisal, information from the social environment can be used to modify the stimulus' meaning. This study investigated whether perspective taking changes participants' brain potentials to unpleasant pictures.

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Dec
1969

Structural brain imaging studies in obsessive-compulsive disorder (OCD) have produced inconsistent findings. This may be partially due to limited statistical power from relatively small samples and clinical heterogeneity related to variation in illness profile and developmental stage. To address these limitations, the authors conducted meta- and mega-analyses of data from OCD sites worldwide.

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Dec
1969

Individuals with body dysmorphic disorder (BDD) and obsessive-compulsive disorder (OCD) are categorized within the same major diagnostic group and both show regional brain hyperactivity in the orbitofrontal cortex (OFC) and the basal ganglia during symptom provocation. While recent studies revealed that degree connectivity of these areas is abnormally high in OCD and positively correlates with symptom severity, no study has investigated degree connectivity in BDD. We used functional magnetic resonance imaging (fMRI) to compare the local and distant degree of functional connectivity in all brain areas between 28 unmedicated BDD participants and 28 demographically matched healthy controls during a face-processing task.

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Dec
1969

As a functional organization principle in cortical visual information processing, the influential 'two visual systems' hypothesis proposes a division of labor between a dorsal "vision-for-action" and a ventral "vision-for-perception" stream. A core assumption of this model is that the two visual streams are differentially involved in visual awareness: ventral stream processing is closely linked to awareness while dorsal stream processing is not. In this functional magnetic resonance imaging (fMRI) study with human observers, we directly probed the stimulus-related information encoded in fMRI response patterns in both visual streams as a function of stimulus visibility.

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Nov
2016

Clinical and theoretical models suggest deficient volitional initiation of action in schizophrenia patients. Recent research provided an experimental model of testing this assumption using saccade tasks. However, inconsistent findings necessitate a specification of conditions on which the deficit may occur.

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Sep
2016

Patients with borderline personality disorder (BPD) show deficits in reward-guided decision making and learning. The present study examined risk-taking behavior in combination with feedback processing. Eighteen BPD patients and 18 healthy controls performed a probabilistic two-choice gambling task, while an electroencephalogram was recorded.

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Dec
1969

Self-control can be defined as the ability to exert control over ones impulses. Currently, most research in the area relies on self-report. Focusing on attentional control processes involved in self-control, we modified a spatial selective attentional cueing task to test three domains of self-control experimentally in one task using aversive, tempting, and neutral picture-distractors.

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Dec
1969

Confrontation with anxiety-provoking situations is an effective treatment for anxiety disorders. However, underlying processes of the effects of exposure and its prevention by avoidance are barely understood. We investigated consequences of repeatedly withdrawing attention from or maintaining it to unpleasant images using ERPs.

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Jul
2016

As indicated by previous research, aging is associated with a decline in working memory (WM) functioning, related to alterations in fronto-parietal neural activations. At the same time, previous studies showed that WM training in older adults may improve the performance in the trained task (training effect), and more importantly, also in untrained WM tasks (transfer effects). However, neural correlates of these transfer effects that would improve understanding of its underlying mechanisms, have not been shown in older participants as yet.

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Jul
2016

Behavioral choice can be characterized along two axes. One axis distinguishes reflexive, model-free systems that slowly accumulate values through experience and a model-based system that uses knowledge to reason prospectively. The second axis distinguishes Pavlovian valuation of stimuli from instrumental valuation of actions or stimulus-action pairs.

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Dec
1969

Uncertainty about future threat has been found to be associated with an overestimation of threat probability and is hypothesized to elicit additional allocation of attention. We used event-related potentials to examine uncertainty-related dynamics in attentional allocation, exploiting brain potentials' high temporal resolution and sensitivity to attention. Thirty participants performed a picture-viewing task in which cues indicated the subsequent picture valence.

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Feb
2016

Body dysmorphic disorder (BDD) is characterized by preoccupation with perceived flaws in one's own appearance. Several risk factors such as aesthetic perceptual sensitivity have been proposed to explain BDD's unique symptomatology. Although research on facial discrimination is limited so far, the few existing studies have produced mixed results.

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Feb
2016

Brain correlates of performance-monitoring have been shown to be hyperactive in patients with obsessive-compulsive disorder (OCD), indexed by enhanced amplitudes of the error-related negativity (ERN) in the event-related potential (ERP). This hyperactivity was found to be temporally stable, independent of symptom remission, and could not be further increased by punishing committed errors. The current study examined whether the ERN in OCD is generally insensitive to modulatory influences or can be decreased by manipulation of task demands.

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Aug
2015

Both obsessive-compulsive disorder and subclinical obsessive-compulsive (OC) symptoms seem to be associated with hyperactive error-related brain activity. The current study examined performance monitoring in subjects with subclinical OC symptoms using a new task with different levels of difficulty. Nineteen subjects with high and 18 subjects with low OC characteristics performed a random dot cinematogram (RDC) task with three levels of difficulty.

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May
2016

In detoxified alcohol-dependent patients, alcohol-related stimuli can promote relapse. However, to date, the mechanisms by which contextual stimuli promote relapse have not been elucidated in detail. One hypothesis is that such contextual stimuli directly stimulate the motivation to drink via associated brain regions like the ventral striatum and thus promote alcohol seeking, intake and relapse.

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Jul
2015

Overactive performance monitoring, as measured by the error-related negativity in the event-related brain potential, represents one of the most robust psychophysiological alterations in obsessive-compulsive disorder (OCD). It has been proposed as an endophenotype for OCD because it is heritable and more prevalent in families of OCD patients. Consistent with this notion, it is also independent of symptom profile and symptom severity in cross-sectional studies.

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Oct
2016

Hyperactive performance monitoring, as measured by the error-related negativity (ERN) in the event-related potential, is a reliable finding in obsessive-compulsive disorder (OCD) research and may be an endophenotype of the disorder. Imaging studies revealed inconsistent results as to which brain regions are involved in altered performance monitoring in OCD. We investigated performance monitoring in OCD with simultaneous recording of electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) signals to determine the neural source of the enhanced ERN.

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Oct
2016

Several studies have demonstrated a bilateral field advantage (BFA) in early visual attentional processing, that is, enhanced visual processing when stimuli are spread across both visual hemifields. The results are reminiscent of a hemispheric resource model of parallel visual attentional processing, suggesting more attentional resources on an early level of visual processing for bilateral displays [e.g.

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Jul
2015

The posterior parietal cortex (PPC) and the dorsolateral prefrontal cortex (DLPFC) are known to be part of a cortical network involved in visual spatial attention. Top-down control can modulate processing at target and distractor positions over a sequence of trials, leading to positive priming at prior target positions and negative priming at prior distractor positions. In order to elucidate the exact time course of this top-down mechanism we here propose a transcranial magnetic stimulation (TMS) protocol.

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Dec
1969

Human and animal work suggests a shift from goal-directed to habitual decision-making in addiction. However, the evidence for this in human alcohol dependence is as yet inconclusive.
Twenty-six healthy controls and 26 recently detoxified alcohol-dependent patients underwent behavioral testing with a 2-step task designed to disentangle goal-directed and habitual response patterns.

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Dec
1969

Pavlovian processes are thought to play an important role in the development, maintenance and relapse of alcohol dependence, possibly by influencing and usurping ongoing thought and behavior. The influence of pavlovian stimuli on ongoing behavior is paradigmatically measured by pavlovian-to-instrumental transfer (PIT) tasks. These involve multiple stages and are complex.

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Nov
2014

Overactive performance monitoring, indexed by greater error-related brain activity, has been frequently observed in individuals with obsessive-compulsive disorder (OCD). Similar alterations have been found in individuals with major depressive and generalized anxiety disorders. The main objective was to extend these findings by investigating performance monitoring in individuals with social anxiety disorder (SAD) and to evaluate the specificity of performance-monitoring changes in OCD.

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Jan
2015

Recent behavioral and neuroimaging studies using continuous flash suppression (CFS) have suggested that action-related processing in the dorsal visual stream might be independent of perceptual awareness, in line with the "vision-for-perception" versus "vision-for-action" distinction of the influential dual-stream theory. It remains controversial if evidence suggesting exclusive dorsal stream processing of tool stimuli under CFS can be explained by their elongated shape alone or by action-relevant category representations in dorsal visual cortex. To approach this question, we investigated category- and shape-selective functional magnetic resonance imaging-blood-oxygen level-dependent responses in both visual streams using images of faces and tools.

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Nov
2014

Although neurobiological models of obsessive-compulsive disorder (OCD) traditionally emphasise the central role of corticostriatal brain regions, studies of default mode network integrity have garnered increasing interest, but have produced conflicting results.
To resolve these discrepant findings by examining the integrity of default mode network subsystems in OCD.
Comparison of seed-based resting-state functional connectivity of 11 default mode network components between 46 patients with OCD and 46 controls using functional magnetic resonance imaging.

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Dec
1969

Anxiety disorders have been linked to a hyperactivated cortico-amygdalar circuitry. Recent findings highlight the amygdala's role in mediating elevated anxiety in obsessive-compulsive disorder (OCD). However, modulation of amygdala hyperactivation by attentional distraction - an effective emotion regulation strategy in healthy individuals - has not yet been examined.

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Aug
2014

The present study investigated the modulation of the N2 and the correct-related negativity (CRN) by conflict frequency. Conflict costs, as measured by reaction times and error rate, were reduced with increasing conflict frequency, indicating improved conflict resolution. N2 amplitudes in incompatible trials increased with higher conflict frequency, while postresponse CRN amplitudes decreased.

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Dec
2014

Overactive performance monitoring has been consistently reported in obsessive-compulsive disorder (OCD). OCD is a clinically heterogeneous disorder and is characterized by several symptom dimensions that may have partially distinct neural correlates. We examined whether performance-monitoring alterations are related to symptom severity and symptom dimensions.

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Jul
2014

Hemispheric topography of alpha band power in the electroencephalogram has been linked to approach/avoidance motivation and may index the risk for anxiety disorders and depression. We quantified lower alpha band power (8-10 Hz) in 20 patients with obsessive-compulsive disorder (OCD) and 20 matched healthy controls during blocks of rest and presentation of neutral, aversive, and OCD-related pictures. Compared to the control group, OCD patients showed altered asymmetry, with frontal alpha power in the 8-10 Hz band being more dominant in the left hemisphere across all conditions.

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Sep
2014

Hyperactive performance monitoring is a robust finding in obsessive-compulsive disorder (OCD). Patients show increased amplitudes of the error-related negativity (ERN) and correct-related negativity (CRN). Recently, two temporo-spatial factors were shown to contribute to both ERPs in healthy individuals.

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Aug
2014

Although electroconvulsive therapy (ECT) is the most effective acute antidepressant intervention, sustained response rates are low. It has never been systematically assessed whether psychotherapy, continuation ECT, or antidepressant medication is the most efficacious intervention to maintain initial treatment response.
In a prospective, randomized clinical trial, 90 inpatients with major depressive disorder (MDD) were treated with right unilateral ultra-brief acute ECT.

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Jan
2014

In the domain of working memory (WM), a sigmoid-shaped relationship between WM load and brain activation patterns has been demonstrated in younger adults. It has been suggested that age-related alterations of this pattern are associated with changes in neural efficiency and capacity. At the same time, WM training studies have shown that some older adults are able to increase their WM performance through training.

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Apr
2014

Cognitive-behavioral models of body dysmorphic disorder (BDD) suggest the disorder is characterized by several interpretive, attentional, and perceptual biases that contribute to its maintenance or even development. In addition, the role of aesthetic sensitivity has been discussed in BDD. However, previous research examining the ability to identify subtle changes in facial features and geometrical objects has produced mixed results.

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Feb
2014

Response accuracy ratings are often used in studies investigating the relationship between ERP correlates of performance monitoring and error awareness. Still, it is unclear whether the act of rating response correctness changes ERP correlates of performance monitoring. In order to investigate the influence of response accuracy ratings, a flanker task was conducted with or without concomitant accuracy rating and ERPs were compared between the two conditions.

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Oct
2013

Elevated anxiety in obsessive-compulsive disorder (OCD) has been linked to cortico-limbic hyperactivation, whereas hyperarousal of the autonomous nerve system (ANS) has inconsistently been found. We investigate ANS functioning during symptom provocation with individually tailored OCD-relevant pictures in 14 unmedicated patients and 14 controls and link it to activation in brain areas involved in ANS regulation. In addition to OCD-triggers, aversive and neutral control stimuli were included.

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Sep
2014

Hypnosis can affect perception, motor function and memory. However, so far no study using neuroimaging has investigated whether hypnosis can influence reward processing and decision-making. Here, we assessed whether posthypnotic suggestions can diminish the attractiveness of unhealthy food and whether this is more effective than diminishing attractiveness by one's own effort via autosuggestion.

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Oct
2013

Although externally as well as internally-guided eye movements allow us to flexibly explore the visual environment, their differential neural mechanisms remain elusive. A better understanding of these neural mechanisms will help us to understand the control of action and to elucidate the nature of cognitive deficits in certain psychiatric populations (e.g.

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Sep
2013

Slowed initiation of volitional but not visually guided saccades indicates impaired volitional action control in schizophrenia patients (SZ). The present study aimed at identifying neural correlates of this specific deficit. Fourteen SZ and 13 healthy control participants (HC) underwent functional magnetic resonance imaging while performing volitional and visually guided saccades.

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Sep
2013

Distraction and cognitive reappraisal influence the emotion-generative process at early stages and have been shown to effectively attenuate emotional responding. Inhibiting emotion-expressive behavior is thought to be less beneficial due to later implementation, but empirical results are mixed. Thus, the current study examined the temporal dynamics of these emotion regulation strategies at attenuating the late positive potential (LPP) while participants were shown unpleasant pictures.

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Jun
2013

Neurobiological models of obsessive-compulsive disorder (OCD) predict hyperactivity in brain circuits involving the orbitofrontal cortex and the basal ganglia, but it is unclear whether these areas are also characterized by altered brain network properties.
To determine regions of abnormal degree connectivity in patients with OCD and to investigate whether connectivity measures are affected by antidepressant medication in OCD.
Case-control cross-sectional study using resting-state functional magnetic resonance imaging and a data-driven, model-free method to test for alterations in the degree of whole-brain, distant, and local connectivity in unmedicated patients with OCD compared with healthy controls.

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Dec
1969

Previous studies on working memory training have indicated that transfer to non-trained tasks of other cognitive domains may be possible. The aim of this study is to compare working memory training and transfer effects between younger and older adults (n = 60). A novel approach to adaptive n-back training (12 sessions) was implemented by varying the working memory load and the presentation speed.

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