Antisoziale Persönlichkeitsmerkmale und ereigniskorrelierte Potentiale der Feedbackverarbeitung

Die FRN („Feedback-related-Negativity“), ein fronto-zentral auftretendes, ereigniskorreliertes Potential (EKP) mit negativem Wellenverlauf, und die P300, ein zentral-parietal auftretendes EKP mit positiver Amplitude, stehen in Gambling-Paradigmen in Zusammenhang mit Feedbackverarbeitung und Handlungsevaluation. Beide EKPs werden als Manifestationen von Teilprozessen der neuronalen Fehlerverarbeitung angesehen. In der vorliegenden Arbeit wurde die Variation der neuronalen Komponenten in einem Gambling-Paradigma untersucht. Die FRN wurde mit antisozialem Verhalten in Beziehung gesetzt. Basierend auf dem Gambling-Paradigma von Pfabigan et al. (2010a) wurde ein experimentelles Design entworfen, das es erlaubt Erwartungen, die gegenüber positivem und negativem Feedback aufgebaut wurden, experimentell zu manipulieren. Der Zusammenhang zwischen Fehlerverarbeitung von externem Feedback und der Ausprägung antisozialen Verhaltens wurde in einem nicht-sozialen Kontext mit monetärem Anreiz überprüft. Die Hypothesen der vorliegenden Arbeit waren, dass die FRN mit der Valenz des Feedbacks und den Erwartungen gegenüber dem Feedback variiert, mit größeren Amplituden für negatives und unerwartetes Feedback. In Bezug auf antisoziales Verhalten und Psychopathie war die Annahme, dass Probanden mit stärkerer Ausprägung antisozialen Verhaltens erhöhte FRN-Amplituden auf unerwartet negatives Feedback zeigen würden als Personen mit weniger starken Ausprägungen in antisozialem Verhalten. Zusätzlich wurde angenommen, dass die P300 mit der Erwartung variiert, mit größeren Amplituden für unerwartete Ereignisse. Hypothesenkonform konnte eine Variation der FRN-Amplitude mit der Valenz und der Erwartung festgestellt werden, mit höheren Amplituden nach negativem und unerwartetem Feedback. Es konnte kein Zusammenhang der FRN-Amplitude mit der Ausprägung antisozialen Verhaltens festgestellt werden. Es war visuell eine Tendenz zu verringerten FRN-Amplituden bei antisozialen Personen zu erkennen, in der unerwartet-negativen Bedingung sowie in der negativen Kontrollbedingung. Weiters konnte in der P300-Amplitude eine Interaktion zwischen Erwartung und Valenz festgestellt werden, mit höheren Amplituden für unerwartetes, positives Feedback. In Bezug auf das Design ist festzuhalten, dass die Kontrollbedingung ohne Erwartungsmanipulation eine hohe Aufgabenschwierigkeit darstellte. Diese Aufgabenschwierigkeit führte ohne Erwartungsmanipulation zu großen Amplituden in beiden Komponenten. Die Studie hebt den Einfluss der Feedbackerwartung, zusätzlich zur Feedbackvalenz, auf die neuronale Fehlerverarbeitung hervor. Insgesamt kann die FRN als kognitives Korrelat der subjektiven Leistung in der Evaluation der Handlungsplanung angesehen werden. Die Handlung muss dafür als relevant und konsistent gegenüber den Konsequenzen gesehen werden. In den Konsequenzen muss weiter ein motivationaler Mehrwert gesehen werden (Balconi & Crivelli, 2010; Luu et al., 2000; Vidal et al., 2000; Bush et al., 2000; Hajcak et al., 2005). Ausgehend von der aktuellen Literatur und der hier beobachteten Tendenz zu verringerten FRN-Amplituden bei antisozialen Personen in der unerwartet-negativen Bedingung und der negativen Kontrollbedingung, sind weiterführende Untersuchungen über eine Modifikation des experimentellen Paradigmas anzustreben.The study’s aim was to examine amplitude variations of event-related potentials (ERPs), associated with violation of valence and expectation to feedback. The variations of the ERP components were examined in a learning-gambling-task in healthy individuals. Neural correlates of feedback evaluation were examined in relation to antisocial behaviour and psychopathy. The „feedback-related-negativity“ (FRN) is a negative-going, fronto-central ERP component. It is elicited when people receive unfavourable feedback about an action’s outcome. Its amplitude is reported to be largest when consequences are worse than expected (Holroyd & Coles, 2002). A second relevant ERP component is the P300 (or P300b), a positive-going amplitude, which is most prominent over central-parietal electrodes. In previous gambling-tasks its amplitude has been modulated by expectation, attention and motivation (Donchin, 1981; Duncan-Johnson & Donchin, 1977; Yeung & Sanfey, 2004). In the present study these ERP components where examined in a learning-gambling-task, based on the experimental task of Pfabigan et al. (2010a). The modified task version allowed manipulation of feedback valence and expectation to participants’ choices. The hypotheses were that the FRN-amplitude varies with feedback valence and expectation, with larger amplitudes for negative and unexpected feedback. Furthermore, FRN amplitude was assumed to vary with different characteristics of antisocial behaviour, with larger amplitudes when people tend to behave more antisocial. The P300 was thought to vary with feedback expectation, with larger amplitudes for unexpected feedback. Valence, as well as expectation, significantly effected FRN-amplitudes. However, antisocial behaviour did not significantly influence FRN amplitudes. More antisocial participants showed a tendency to FRN amplitude reductions for unexpected negative feedback, which might indicate insufficient feedback monitoring. The interaction between expectation and valence showed a significant effect on P300 amplitudes. This interaction suggests that expectations play a role for feedback monitoring and P300 amplitudes. The present results highlight the impact of valence and expectation on neural feedback monitoring

Sex differences in the functional connectivity of the amygdalae in association with cortisol

Human amygdalae are involved in various behavioral functions such as affective and stress processing. For these behavioral functions, as well as for psychophysiological arousal including cortisol release, sex differences are reported.Here, we assessed cortisol levels and resting-state functional connectivity (rsFC) of left and right amygdalae in 81 healthy participants (42 women) to investigate potential modulation of amygdala rsFC by sex and cortisol concentration.Our analyses revealed that rsFC of the left amygdala significantly differed between women and men: Women showed stronger rsFC than men between the left amygdala and left middle temporal gyrus, inferior frontal gyrus, postcentral gyrus and hippocampus, regions involved in face processing, inner-speech, fear and pain processing. No stronger connections were detected for men and no sex difference emerged for right amygdala rsFC. Also, an interaction of sex and cortisol appeared: In women, cortisol was negatively associated with rsFC of the amygdalae with striatal regions, mid-orbital frontal gyrus, anterior cingulate gyrus, middle and superior frontal gyri, supplementary motor area and the parietal–occipital sulcus. Contrarily in men, positive associations of cortisol with rsFC of the left amygdala and these structures were observed. Functional decoding analyses revealed an association of the amygdalae and these regions with emotion, reward and memory processing, as well as action execution.Our results suggest that functional connectivity of the amygdalae as well as the regulatory effect of cortisol on brain networks differs between women and men. These sex-differences and the mediating and sex-dependent effect of cortisol on brain communication systems should be taken into account in affective and stress-related neuroimaging research. Thus, more studies including both sexes are required

Neurobiological Divergence of the Positive and Negative Schizophrenia Subtypes Identified on a New Factor Structure of Psychopathology Using Non-negative Factorization:An International Machine Learning Study

ObjectiveDisentangling psychopathological heterogeneity in schizophrenia is challenging and previous results remain inconclusive. We employed advanced machine-learning to identify a stable and generalizable factorization of the “Positive and Negative Syndrome Scale (PANSS)”, and used it to identify psychopathological subtypes as well as their neurobiological differentiations.MethodsPANSS data from the Pharmacotherapy Monitoring and Outcome Survey cohort (1545 patients, 586 followed up after 1.35±0.70 years) were used for learning the factor-structure by an orthonormal projective non-negative factorization. An international sample, pooled from nine medical centers across Europe, USA, and Asia (490 patients), was used for validation. Patients were clustered into psychopathological subtypes based on the identified factor-structure, and the neurobiological divergence between the subtypes was assessed by classification analysis on functional MRI connectivity patterns.ResultsA four-factor structure representing negative, positive, affective, and cognitive symptoms was identified as the most stable and generalizable representation of psychopathology. It showed higher internal consistency than the original PANSS subscales and previously proposed factor-models. Based on this representation, the positive-negative dichotomy was confirmed as the (only) robust psychopathological subtypes, and these subtypes were longitudinally stable in about 80% of the repeatedly assessed patients. Finally, the individual subtype could be predicted with good accuracy from functional connectivity profiles of the ventro-medial frontal cortex, temporoparietal junction, and precuneus.ConclusionsMachine-learning applied to multi-site data with cross-validation yielded a factorization generalizable across populations and medical systems. Together with subtyping and the demonstrated ability to predict subtype membership from neuroimaging data, this work further disentangles the heterogeneity in schizophrenia