MAGNETIC SOURCE IMAGING EVIDENCE OF SEX-DIFFERENCES IN CEREBRAL LATERALIZATION IN SCHIZOPHRENIA

Background: It has been postulated that schizophrenia represents a dis order of anomalous cerebral lateralization. This study is a replicatio n of earlier preliminary findings using a multichannel neuromagnetomet er, suggesting altered lateralization in schizophrenia in male subject s, with an extension of the findings to female subjects. Methods: We u sed magnetoencephalography-based magnetic source imaging to estimate t he intracranial location of the 100-millisecond latency auditory-evoke d field component (M100) in both left and right hemispheres of 20 pati ents with paranoid schizophrenia and 20 controls without schizophrenia . Neuroanatomical data were obtained by means of magnetic resonance im aging, from which we segmented and computed volumes of both total brai n and left and right superior temporal gyri. Results: Locations of M10 0 source were compatible with neuronal generators located in the trans verse gyri of Heschl on the superior temporal gyri in both study group s; M100 sources were asymmetric in all the control subjects. The male patient subgroup exhibited significantly less asymmetry than the contr ol group, while the female patient subgroup actually showed significan tly more asymmetry. The male patient subgroup generally had smaller su perior temporal gyri than the control group. No evidence of total brai n volume differences was observed. Conclusions: Our findings support p revious magnetoencephalography-based studies suggesting anomalous cere bral lateralization in schizophrenia. Further, in extending our studie s to female patients, our data suggest that the nature of this anomaly is sex specific, a finding that, to our knowledge, has not previously been reported.