From Philipps-University Marburg, Kim Wende, PhD, will give a talk entitled "Neural correlates of physical and social causality judgments in response to animated visual stimuli: a set of fMRI experiments involving healthy subjects and patients with schizophrenia"
In her abstract, she informs us that "Patients with schizophrenia often maintain deviating views on cause-effect relationships, leading to delusional inferences. However, up to now it is unknown, whether alterations in causal impressions are related to perceptual dysfunctions or rather aberrant inferential processes. Here we investigated the neural correlates of causality judgments in patients with schizophrenia using comparable physical and social visual stimuli. During functional magnetic resonance imaging data acquisition patients and matched controls were presented with two types of animated videos: A blue ball colliding with a red ball (physical condition), and a blue ball passing the red ball and then straying off the track (social condition; here, subjects were instructed to imagine the balls as persons). Participants judged causality (causality task) vs. movement direction (control task). Spatio-temporal stimulus-parameters were varied equally for both video types.
Behaviorally, groups differed significantly with respect to causal responses (yes/no); patients showed more physical causal judgments and less social causal judgments than controls. In the patient group, spatio-temporal stimulus-characteristics contributed less to causal judgments in both contexts. At the neural level, both groups showed large overlaps in task-related (causality > control) neural activation in a predominantly right fronto-parietal network. Additionally, patients showed increased neural activity in the left inferior frontal gyrus (l.IFG) for causality in contrast to direction judgments, specifically pronounced in the social context. L.IFG activity in patients for causality>direction judgments was correlated with SAPS delusion subscale sum scores. Psycho-physiological interaction (PPI) analyses further revealed a significant decrease of functional connectivity between the l.IFG and bilateral occipito-parietal brain regions in patients.
As behavioral results show that perceptual stimulus parameters are less relevant for causal judgments in patients with schizophrenia than in healthy controls, increased frontal activity during causality judgments might reflect altered inferential judgment strategies in the patient group. Possibly, patients apply interpretational strategies (manifesting in a symptom-related over-attribution of non-social causal relations, and under-estimation of social causal relations) as compensation for perceptual integration dysfunctions resulting from frontal disconnectivity to posterior regions processing visual-perceptual cue information. The results shed light into the neural correlates of delusional inferences in patients".
This talk will take place on Friday 6th of September in Séminaire Martin V, 42 B, in Woluwé at 13:00.