Universität Tübingen
Neural representation of conceptual knowledge in schizophrenic patients. An fMRI study.
Abstract
Neural representation of conceptual knowledge in healthy subjects has already been investigated by lesion studies, as well as by functional neuro-imaging experiments, resulting in the implementation of mainly three different theories to explain the obtained data. Here, we investigate the representation of semantic concepts by studying the processing of “living” and “non-living” categories in schizophrenic patients, as compared to healthy controls. Distinction between “living” and “nonliving” constitutes an important aspect of social cognition where schizophrenic patients are impaired. We used a set of complex and naturalistic stimuli from a standardized picture data base (IAPS) to compare the differential brain activation induced by different categorical stimuli (humans, animals, food, tools). 11 schizophrenic patients and 15 healthy controls were measured with fMRI while watching the pictorial stimuli and performing a categorization task (discrimination between “living” and “nonliving” stimuli which were presented in a randomized order). A fronto-parietal network comprising orbito-frontal regions and regions at the occipito-temporal junction, as well as the superior temporal sulcus (STS) was found to be more strongly activated by “living” stimuli (human, animal) than by “nonliving” stimuli (food, tool), supporting the theory that conceptual knowledge is stored in a specialized network of brain areas, differentially active when representing and processing entities belonging to different categories. During the differential contrast for the living category (“living” items minus “nonliving” items), schizophrenic patients show less activation in the left occipito-temporal region, a region typically involved in processing cognitive skills important for social behavior. We conclude that an altered representation of socially meaningful stimuli might contribute to social deficits in schizophrenia and discuss how these findings might be connected to the symptoms of formal thought disorder and delusions in schizophrenia.
Author and committee
dc:creator, dc:contributor.*- Author
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- Holzwarth, Dorothea Anne
Identifiers
dc:identifier.*- Identifier
- hdl:10900/45386