The human brain is laterally asymmetric. Although anatomic structures on the left tend to resemble their homologous structure on the right, there are consistent and functionally important differences between them, particularly in the posterior temporal lobe areas involved in language processing. Postmortem and in-vitro imaging studies have reported several consistent left-right differences. The planum temporal (PT) is, on the average, larger on the left than the right. This surface is intimately related to Wernicke's region in the left posterior temporal lobe. Yet, because previous investigators used varying anatomical criteria for PT and different methods for measuring it, comparison between studies proves difficult,and no prior method seems ideal. Previous work suggests that the normal asymmetry of the PT may be altered in some schizophrenic patients' brains. There is increasing evidence that some cardinal symptoms of schizophrenia (hallucinations and though disorder) are associated with changes in the left temporal lobe, suggesting that the PT's changes may be related to schizophrenic symptoms. The proposed study aims to compare the contrast new and old MRI measures of the PT in normals. A second goal is to apply these measurements to the PTs of schizophrenic patients and carefully matched controls. Finally, based on previous findings, we hypothesize that the degrees of left-right asymmetry of the PT is likely to correlate with specified positive symptoms of schizophrenia. If this is true, it would further the understanding of the biological basis of the disorder, provide a possible marker for an identifiable subgroup of schizophrenia (which is probably a heterogeneous disorder), and suggest some connection between these symptoms and several other active areas within neuroscience research, particularly the study of language, gender differences, and structural and functional brain asymmetries.
| Buchanan, R W; Vladar, K; Barta, P E et al. (1998) Structural evaluation of the prefrontal cortex in schizophrenia. Am J Psychiatry 155:1049-55 |
| Barta, P E; Pearlson, G D; Brill 2nd, L B et al. (1997) Planum temporale asymmetry reversal in schizophrenia: replication and relationship to gray matter abnormalities. Am J Psychiatry 154:661-7 |
