HIPPOCAMPAL MORPHOMETRY IN SCHIZOPHRENIA BY HIGH-DIMENSIONAL BRAIN MAPPING

Theories of the pathophysiology of schizophrenia have implicated the h ippocampus, but controversy remains regarding hippocampal abnormalitie s in patients with schizophrenia, Irt vivo studies of hippocampal anat omy using high resolution magnetic resonance scanning and manual metho ds for volumetric measurement have yielded inconclusive results, perha ps because of the normal variability in hippocampal volume and the err or involved in manual measurement techniques. To resolve this controve rsy, high dimensional transformations of a computerized brain template mere used to compare hippocampal volumes and shape characteristics in 15 matched pairs of schizophrenia and control subjects. The transform ations were derived from principles of general pattern matching and we re constrained according to the physical properties of fluids, The ana lysis and comparison of hippocampal shapes based on these transformati ons were far superior to the comparison of hippocampal volumes or othe r global indices of hippocampal anatomy in showing a statistically sig nificant difference between the two groups. In the schizophrenia subje cts, hippocampal shape deformations were found to be localized to subr egions of the structure that send projections to prefrontal cortex. Th e results of this study demonstrate that abnormalities of hippocampal anatomy occur in schizophrenia and support current hypotheses that sch izophrenia involves a disturbance of hippocampal-prefrontal connection s. These results also show that comparisons of neuroanatomical shapes can be more informative than volume comparisons for identifying indivi duals with neuropsychiatric diseases, such as schizophrenia.