An association between reduced interhemispheric EEG coherence in the temporal lobe and genetic risk for schizophrenia

Previous studies have suggested that schizophrenic patients show resting EE G replicate the results on the second data set. power spectrum analysis sug gested that schizophrenics are cortically hypoactivated, whereas in unaffec ted siblings, a tendency for hyperactivation was found. In contrast, spectr al coherences (0.5-5 Hz) were reduced in both data sets in the temporal lob e areas in schizophrenics and in their unaffected siblings. Changes were mo st pronounced for the interhemispheric coherence linking both posterior tem poral lobe areas. Relative risk calculations (hs) ranged between 3.7 and 9. 8, depending on phenotype definition. Thus, while power spectrum EEG abnorm alities may be state-dependent, reduced coherence as a possible measure of neuronal synchronization is familial and potentially a heritable trait rela ted to genetic risk for schizophrenia. (C) 2001 Elsevier Science B.V. All r ights reserved.