SIZE, SHAPE, AND ORIENTATION OF NEURONS IN THE LEFT AND RIGHT HIPPOCAMPUS - INVESTIGATION OF NORMAL ASYMMETRIES AND ALTERATIONS IN SCHIZOPHRENIA

Objective: Schizophrenia may involve the two cerebral hemispheres diff erentially. This study was conducted to determine whether left and rig ht hippocampal neuronal size, shape, and orientation are normally asym metrical or asymmetrically affected in schizophrenia. Method: The auth ors examined postmortem tissue from the left and right hippocampus of 17 normal individuals and 14 individuals with schizophrenia. They meas ured the size, shape, ann variability in orientation of pyramidal neur ons in hippocampal subfields CA1-CA4 and the subinculum in computer im ages of 10-mu m coronal sections stained with cresyl violet. Results: Both neuronal size and shape showed significant effects of diagnosis a nd a three-way interaction between diagnosis, hemisphere, and subfield . Neurons of the schizophrenic subjects were smaller than those oi the normal subjects in the left CA1, left CA2, and right CA3 subfields; t heir shape differed from that of the normal subjects in the left CA1, left subiculum, and right CA3 subfields. There were no group differenc es in variability of neuronal orientation, but neurons in the CA3 genu in the schizophrenic subjects were less variable on the right than on the left. In the normal subjects, except for larger neurons in the le ft than in the right CA2 subfield and some left-right differences in v ariability of neuronal orientation, no statistically significant asymm etries were observed. Conclusions: The data confirm that hippocampal n euronal size is decreased in schizophrenia and reveal that the shape o f neurons is altered, supporting the view that hippocampal cytoarchite ctural abnormalities may be part of the cerebral substrate of schizoph renia. They also provide further evidence that the abnormalities are l ocalized and lateralized.