Evaluating implicit attractiveness beliefs in body dysmorphic disorder using the Go/No-go Association Task

Cognitive-behavioral models of body dysmorphic disorder (BDD) suggest the disorder is characterized by exaggerated beliefs about the significance of appearance. However, previous studies assessing automatic associations regarding the importance of attractiveness failed to find any differences between individuals with BDD and healthy control participants using the Implicit Association Test (IAT; Greenwald, McGhee, & Schwartz, 1998). An open question is whether the BDD and control groups indeed implicitly evaluate attractiveness comparably, or whether methodological factors (e.g., the IAT design requirement of a relative comparison category for attractiveness) made it difficult to observe group differences. To address this question, we evaluated explicit and implicit attractiveness beliefs among individuals with BDD (n = 36), individuals with a dermatological condition (n = 36), and psychiatrically healthy control participants (n = 36) using the single target category Go/No-go Association Task (GNAT; Nosek, & Banaji, 2001). Indeed, BDD participants had significantly stronger implicit associations between attractive and important, relative to the other groups, whereas there was no difference between the dermatology and control groups. Further, the GNAT was effective at classifying individuals with BDD above and beyond the prediction offered by an explicit measure of attractiveness beliefs. The GNAT may be a useful tool for assessing implicit associations in clinical populations because it does not require an explicit comparison target category, which is a restriction of many implicit measures.

Overactive error-related brain activity as a candidate endophenotype for obsessive-compulsive disorder: evidence from unaffected first-degree relatives

OBJECTIVE

Hyperactivity in frontal-striatal circuits is assumed to be involved in the pathophysiology of obsessive-compulsive disorder (OCD). In line with that, electrocortical correlates of overactive performance monitoring have been found to be associated with OCD independent from symptom state. The purpose of the present study was to elucidate whether overactive performance monitoring may represent a candidate endophenotype for OCD. In this case, unaffected first-degree relatives of OCD patients should also show this trait.

METHOD

Amplitudes of the error-related negativity and the correct-related negativity in the event-related brain potential during a flanker task were used to assess performance monitoring in three carefully matched groups: 30 patients with OCD, 30 unaffected first-degree relatives of OCD patients, and 30 healthy comparison subjects.

RESULTS

Relative to the healthy comparison subjects, both unaffected first-degree relatives and OCD patients showed increased error-related brain potentials. No significant correlation was obtained between amplitudes and symptom severity measures, neither in patients nor in first-degree relatives.

CONCLUSIONS

Increased error-related brain potentials were observed not only in OCD patients but also in unaffected first-degree relatives. Overactive error monitoring may reflect a trait marker for OCD that is independent of the presence of clinical symptoms. Thus, enhanced error-related brain activity represents a candidate neurocognitive endophenotype for OCD.

Approach and avoidance learning in obsessive-compulsive disorder

BACKGROUND

Current neurobiological models of obsessive-compulsive disorder (OCD) propose a dysfunction of cortico-striato-thalamo-cortical circuits that leads to enhanced activity in frontal and striatal brain regions. In accordance with that, OCD patients show alterations in learning and flexible adaptation to changing task requirements. The purpose of this study was to examine feedback-based learning and to investigate whether learning from positive and negative feedback is differentially altered in OCD.

METHODS

In this study, 18 OCD patients and 18 healthy comparison subjects conducted a probabilistic selection task. The task consisted of an acquisition and a test phase and allowed disentangling the extent of learning based on positive and negative feedback.

RESULTS

Groups did not differ during probabilistic feedback learning in the acquisition phase. In the test phase, OCD patients showed a negative learning bias in contrast to comparison subjects who showed a positive learning bias. Patients were better at avoiding stimuli that were initially associated with negative outcomes than at approaching stimuli that were associated with positive feedbacks. This interaction was also found for reaction times in that patients were faster in avoiding negative and slower in approaching positive stimuli.

CONCLUSION

Enhanced avoidance learning was found in OCD patients that points to exaggerated anticipation and avoidance of aversive outcomes. Further studies are required to investigate whether neurobiological mechanisms, such as dopaminergic signaling or outcome processing, in the orbitofrontal cortex relate to enhanced negative learning in OCD.

Aging, probabilistic learning and performance monitoring

This study examined age-related alterations in electrocortical indices of performance monitoring in a probabilistic learning situation. The results showed differences between younger and older adults in the modulation of response- and feedback-related negativities by feedback validity. In younger adults, the error-related negativity/error negativity (ERN/Ne) was larger than the correct response-related negativity (CRN) in the high and medium feedback validity condition, whereas the feedback-related negativity (FRN) differentiated between positive and negative feedback in the low feedback validity condition. In older adults, amplitudes of the ERN/Ne and the CRN were dissociated only in the high feedback validity condition and the FRN did not differ between positive and negative feedback. This finding might suggest that performance monitoring is more prone to interference by probabilistic information in older adults. Further, the salience of negative feedback seems reduced with age.

Evidence for specific cognitive deficits in visual information processing in patients with OCD compared to patients with unipolar depression

OBJECTIVE

Neuropsychological studies comparing cognitive performance in patients suffering from Obsessive-Compulsive Disorder (OCD) or Major Depressive Disorder (MDD) revealed deficits in the domains of verbal fluency and viso-motor speed/set shifting in both groups. Spatial working memory deficits, however, have been identified as specific markers of OCD. As yet, it has not been substantiated whether deficits in visual organization and complex visual memory are also specific to OCD and are not shared by MDD.

METHOD

Test performance in seven cognitive domains was assessed in 40 OCD patients, 20 MDD patients, and 40 healthy controls. Patient groups were matched according to severity of depressive symptoms.

RESULTS

Deficits shared by both patient groups, as compared to controls, were found in delayed spatial recall and verbal fluency while verbal memory was normal in both patient groups. Only patients with OCD, but not MDD patients were impaired in the domains visual memory, viso-motor speed/set shifting, visual organization, and problem solving. In addition, OCD patients differed significantly from MDD subjects in visual organization and problem solving. Visual organization scores correlated significantly with severity of current compulsions in the OCD group (r=-.324).

CONCLUSIONS

OCD patients demonstrate difficulties in visual organization and mental manipulation of complex visual material, which are not accounted for by depressive symptoms and which constitute a specific cognitive deficit of the disorder.

Distinct neural correlates for volitional generation and inhibition of saccades

The antisaccade task has proven highly useful in basic and clinical neuroscience, and the neural structures involved are well documented. However, the cognitive and neural mechanisms that mediate task performance are not yet understood. An event-related fMRI study was designed to dissociate the neural correlates of two putative key functions, volitional saccade generation and inhibition of reflexive saccades, and to investigate their interaction. Nineteen healthy volunteers performed a task that required (a) to initiate saccades volitionally, either with or without a simultaneous demand to inhibit a reflexive saccade; and (b) to inhibit a reflexive saccade, either with or without a simultaneous demand to initiate a saccade volitionally. Analysis of blood oxygen level-dependent signal changes confirmed a major role of the frontal eye fields and the supplementary eye fields in volitional saccade generation. Inhibition-related activation of a specific fronto-parietal network was highly consistent with previous evidence involved in inhibitory processes. Unexpectedly, there was little evidence of specific brain activation during combined generation and inhibition demands, suggesting that the neural processing of generation and inhibition in antisaccades is independent to a large extent.

Fronto-striato-limbic hyperactivation in obsessive-compulsive disorder during individually tailored symptom provocation

Anxiety disorders have been linked to a hyperactivated cortico-amygdalar circuitry, but the amygdala's role in the pathophysiology of obsessive-compulsive disorder (OCD) remains unclear. This fMRI study examined the cortico-limbic correlates of individually tailored symptom provocation in 14 unmedicated OCD patients and 14 controls. In addition to OCD-relevant pictures, aversive and neutral control stimuli were included. Patients showed increased fronto-striatal activation to OCD-relevant stimuli contrasted with both control categories. Briefly presented symptom-related triggers elicited stronger amygdala engagement in patients than in controls. This effect, however, did also occur to aversive stimuli and was not symptom specific. Augmented amygdala involvement in patients reflects general emotional hyperarousal. Symptom-specific frontal activation points towards a sustained endeavor to suppress exaggerated emotional responses to OCD triggers.

Response switching in schizophrenia patients and healthy subjects: effects of the inter-response interval

Schizophrenia patients show impaired saccadic response switching, pointing to action control deficits at the level of response selection. Previous studies on healthy subjects suggested that response switch effects might decrease if the prior response is longer ago, reflecting a slow dissipation of the response program persisting from the previous trial. The present study aimed at directly investigating whether response switch effects in schizophrenia patients and healthy subjects depend on the inter-response interval (IRI). Effects of response switching on pro- and antisaccade performance were analyzed in 19 schizophrenia patients and 19 healthy controls at 3 different IRIs (2,500, 3,000, 4,000 ms). Response switch effects of healthy subjects did not vary with the IRI, suggesting that the previous response program persists as long as no contrary response program is activated. In schizophrenia, response switch deficits were replicated at an IRI of 3,000 ms, whereas at IRIs of 2,500 and 4,000 ms, effects of response switching did not significantly differ from healthy subjects. This might suggest that there is a specific IRI range particularly sensitive to response switch deficits in schizophrenia. However, effects of response switching at different IRIs remain to be consolidated.

Overactive performance monitoring in obsessive-compulsive disorder: ERP evidence from correct and erroneous reactions

Obsessive-compulsive disorder (OCD) has repeatedly been associated with hyperactivity in fronto-striatal brain regions and regions related to performance monitoring. The aim of the current study was to further investigate electrophysiological correlates of performance monitoring. Specifically, we intended to replicate previous results revealing enhanced error-related negativity (ERN) amplitudes in OCD patients. Furthermore, we examined whether OCD patients also showed alterations regarding the correct-related negativity (CRN), the error positivity (Pe) and behavioural correlates of performance monitoring. Event-related brain potentials (ERPs) were recorded from a group of 20 OCD patients and 20 healthy control participants during a modified flanker task. Force sensitive response buttons were utilized to separate correct trials from incorrect trials with full and partial response activation. Both groups displayed substantial ERN and Pe amplitudes for full and partial errors. On error trials OCD patients showed enhanced ERN amplitudes, but group differences were not significant for the Pe and for behavioural adjustment. Further, the OCD group also exhibited enhanced CRN amplitudes and a correlation of frontal CRN amplitudes with symptom severity. These data provide further support for the view that performance monitoring is overactive in OCD. Further, since the amplitude enhancement is not specific to error processing, but is also observed for correct reactions, a response monitoring or evaluation process that contributes to both ERP components might be overactive in OCD. This is in line with fMRI results that revealed higher error- and conflict-related activity in the medial frontal cortex in OCD patients.

ERP correlates of conscious error recognition: aware and unaware errors in an antisaccade task

Event-related potential (ERP) studies identified the error-related negativity (Ne/ERN) and the error positivity (Pe) to be associated with performance errors. However, the functional significance of these components is not yet resolved. With the present study we intended to further investigate to what extent these components are related to error awareness. ERPs were recorded during an antisaccade task, and error awareness was obtained from accuracy ratings on each trial. In accordance with earlier findings, aware and unaware errors did not differ in Ne/ERN amplitude. Whereas the late Pe (400-600 ms) shows an increased parietal positivity for aware compared with unaware errors, the early Pe (200-300 ms) shows no dissociation between aware and unaware errors. These data lend further support to the view that the Ne/ERN and the (late) Pe reflect different processes in performance monitoring. In fact the present results provide a clear replication of [S. Nieuwenhuis et al. (2001) Psychophysiology, 38, 752-760], showing that the Pe is associated with error awareness and remedial action. Furthermore, it has been shown that this is only true for the late Pe, whereas the early Pe like the Ne/ERN is not modulated by error awareness.

Decomposing the neural correlates of antisaccade eye movements using event-related FMRI

The antisaccade task is a model of the conflict between an unwanted reflexive response (which must be inhibited) and a complex volitional response (which must be generated). The present experiment aimed to investigate separately the neural correlates of these cognitive components using a delayed saccade paradigm to dissociate saccade inhibition from generation. Seventeen healthy volunteers completed event-related functional magnetic resonance imaging at 1.5 T during saccades to and away from a peripheral visual target (prosaccades and antisaccades, respectively). Saccades were requested in response to an auditory go signal on average 12 s after peripheral target appearance. It was found that the right supramarginal gyrus showed significantly greater activation during the inhibition phase than the generation phase of the paradigm for both antisaccade and prosaccade trials, suggesting a role in saccade inhibition or stimulus detection. On the other hand, the right lateral frontal eye field and bilateral intraparietal sulcus showed evidence of selective involvement in antisaccade generation. Ventrolateral and dorsolateral prefrontal cortices showed comparable levels of activation in both phases of the task. These areas likely fulfill a more general supervisory role in the volitional control of eye movements, such as stimulus appraisal, task set, and decision making.

Positive predictors for antidepressive response to prefrontal repetitive transcranial magnetic stimulation (rTMS)

Repetitive transcranial magnetic stimulation (rTMS) is a brain stimulation technique which had recently been investigated as a putative antidepressant intervention. However, there is little agreement about clinically useful predictors of rTMS outcome. Therefore, the objective of the present study was to determine whether specific biographical, clinical, and psychopathological parameters are associated with the antidepressant response to rTMS in a large sample of 70 depressive patients. We performed a logistic regression analysis in 70 patients with major depressive disorder treated with rTMS of the left dorsolateral prefrontal cortex testing the predictive value of various domains of the depression syndrome as well as the variables episode duration, degree of treatment resistance, and CORE criteria. Response was defined as a 50% reduction of the initial Hamilton score (HAMD). After two weeks of treatment, 21% of the patients showed a response to rTMS. The binary logistic regression model correctly assigned 86.7% of the responders and 96.4% of the non-responders to their final response group. In the model, a high level of sleep disturbances was a significant predictor for treatment response to rTMS. Also, a low score of treatment resistance and a short duration of episode were positive predictors. These findings provide new evidence that especially pronounced sleep disturbances may be a significant clinical predictor of a response to rTMS. Prospective rTMS studies are necessary to validate the predictive value of the derived model.

Schizophrenia patients show impaired response switching in saccade tasks

Action control deficits of schizophrenia patients result from frontostriatal brain abnormalities and presumably reflect an impairment of selective cognitive processes. This study aimed at dissociating two different levels of action control in saccades toward and away from visual stimuli (pro- and antisaccades). Results of previous studies suggested that task switch effects (between pro- and antisaccades) reflect the persistence of a task-specific production rule and refer to the level of task selection, whereas response switch effects (between leftward and rightward saccades) point to the persistence of a specific response program, referring to the level of response selection. In the present study, task switching and response switching were investigated in 20 schizophrenia patients and 20 control subjects. Groups did not differ concerning task switch effects. In contrast, response switching entailed a stronger enhancement of error rates in patients, suggesting a specific deficit on the level of response selection in schizophrenia. The deficit was associated with spatial working memory capacities, confirming and specifying existing hypotheses on a relationship between working memory and action control.

[Impairments of action control in the context of neuropsychological findings in schizophrenia]

Based on a review of neurobiological and neuropsychological findings in schizophrenia, we illustrate how experimental neuropsychological research contributes to the understanding of schizophrenia. It is shown that cognitive performance deficits are a central feature of schizophrenia. They are closely connected with changes of brain physiology and appear to reflect disturbances of basic cognitive functions. It is difficult to identify these functions, because task performance usually taps various cognitive processes. However, isolation of functions is possible by experimental variation of tasks that require a small number of well defined processes. To illustrate this, we review several recent studies that experimentally analyzed deficits in the control of fast eye movements (saccades). In the antisaccade task schizophrenia patients show distinct, temporally stable and often replicated performance deficits. The reviewed studies suggest that these deficits predominantly reflect a weakness in the volitional initiation of action.

Brain potentials indicate poor preparation for action in schizophrenia

Impaired antisaccade performance in schizophrenia (SZ) may originate from poor task preparation, suggested by low amplitudes of the contingent negative variation (CNV) before antisaccades. To dissociate components of preparation we measured the CNV in standard pro- and antisaccades and a stimulus preceding negativity (SPN) in delayed pro- and antisaccades. In healthy controls the SPN had lower amplitudes than the CNV, reflecting mere stimulus expectation in SPN and combined stimulus expectation and action readiness in CNV. SZ patients had lower CNV amplitudes than controls, but there was no reliable indication of a general SPN reduction, suggesting a particular impairment of action readiness. The CNV and SPN amplitudes of controls were larger if tasks had incongruent (anti) compared to congruent (pro) S-R mappings. This difference was absent in SZ patients, suggesting a failure to activate specific resources for incongruent S-R mappings.

Impaired action control in schizophrenia: The role of volitional saccade initiation

Schizophrenia patients show prefrontal cortex dysfunctions of neurodevelopmental origin, but the cognitive implications of these dysfunctions are not yet understood. This study used experimental variations of oculomotor tasks to evaluate the relative roles of volitional action initiation and the inhibition of reflexive behavior. Thirty schizophrenia patients and 30 control participants performed standard prosaccades (SP), standard antisaccades (SA), delayed prosaccades (DP), and delayed antisaccades (DA). The delayed tasks allowed separating the inhibition of erroneous prosaccades and the initiation of volitional saccades, which coincide in the SA task. Arrow-cued (AC) saccades were used to evaluate initiation without any inhibitory component. Erroneous prosaccades were less frequent in the delayed tasks than in the SA task. Error rates were generally larger in schizophrenia patients than in control participants, but the deficit was smaller in the delayed tasks than in the SA task. Correct saccade latencies of schizophrenia patients were normal in the SP task, but not on conditions of volitional saccade initiation (all other tasks). Volitional saccade latencies were positively correlated with error rates in the schizophrenia group. These results confirm that schizophrenia patients have a specific deficit in initiating volitional action, which may also contribute to the increased error rates.