Progress in neuroimaging contributed greatly to the schizophrenia research, including investigation of the etiological factors. We tested the hypothesis that lack of the normal asymmetry of language activation is familial and that it can be found in both schizophrenic and non-schizophrenic family members. In particular, we wanted to know whether relatives who are supposed to be transmitting liability to the illness also demonstrate the loss of asymmetry of language activation. We studied 5 families with at least two members affected with schizophrenia. Functional imaging (fMRI) was used to study cortical activation during a verbal task in Broca's area and its contralateral homologue in subjects with schizophrenia and their both parents who never manifested any psychotic symptoms but one of them had mother or father with schizophrenia. Schizophrenia patients showed lack of asymmetry of language activation. Parents without schizophrenia among their elderly relatives showed normal asymmetry of language activation. Three of parents who supposedly transmit liability to the illness demonstrated the loss of asymmetry of language activation. Our results suggest that lack of the normal asymmetry of language activation could be one of the inherited etiological factors of schizophrenia.

This work was supported by the research project of the Czech Ministry of Education, CNS 1M0517.