Einfluss schizotyper Persönlichkeitsmerkmale auf funktionelle und strukturelle Parameter von Hirnarealen der Gesichtsverarbeitung bei Gesunden

Schizotypy describes a multidimensional construct based on a range of personality traits within the schizophrenia and psychosis spectrum. They are usually classified as schizophrenia-like personality traits on a subclinical level, which can be divided into three dimensions (i.e. positive, negative, disorganised). The construct of schizotypy can contribute to a better understanding of the schizophrenia and psychosis spectrum. In this study we examined the effect of schizotypy on activation and volume of three brain regions involved in face processing: the ‘fusiform face area’, the ‘occipital face area‘ and the ‘posterior superior temporal sulcus face area’, as regions of the ‘core system’, which are considered face selective areas. We studied 288 psychiatrically healthy subjects and classified schizotypal traits by using the ‘Multidimensional Schizotypy Scale‘. A 3T MRI scanner was used for the acquisition of structural (T1) and functional (task-based fMRI) data using pictures of neutral and emotional (fearful) faces, as well as houses as stimuli. We used general linear models to test the hypothesis of correlation between schizotypy facets and activation/volume of face processing areas, as well as their interaction. We did not find an effect of schizotypy on activation of the core system regions for face processing in general or to their grey matter volume. However, we showed a negative correlation of activation in fusiform face area, posterior superior temporal sulcus face area and disorganised dimension of schizotypy for emotional face processing. Furthermore, we demonstrated a correlation between grey matter volume and activation, but not, as hypothesised, through mediation of volume on the association between the schizotypy dimensions and their activation. Also, we showed an interaction of schizotypy dimensions in the association with volume, although moderation effects were not significant. Our study provides novel insides on how schizotypy affects face processing areas. While our results are not fully in line with the few previous studies on the topic, they also highlight a lack of directly comparable studies. Our findings emphasise a schizotypy effect on fear processing in particular, rather than general face processing. However, activation patterns might be additionally affected after onset of pathology. While in line with finding of the wider schizophrenia and psychosis spectrum, our findings add to a neurobiological continuum model, in this case involving face processing areas. Our study contributes to the neurobiological conceptualisation of the spectrum and adds to the related literature in schizophrenia research. To our knowledge, this is the first study to investigate in a correlative approach the influence of schizotypy on the activation and volume of the areas of the face processing core system, as well as their interaction in a large sample of psychiatrically healthy subjects. It could thus form the basis for subsequent studies, which might add further stimuli with additional emotions and include clinical cohorts.