SYNAPTIC CHANGES IN THE STRIATUM OF SCHIZOPHRENIC CASES - A CONTROLLED POSTMORTEM ULTRASTRUCTURAL-STUDY

Although studies indicate abnormalities in the striatum of schizophren ic people, little information exists on the synaptic changes that may be present at the ultrastructural level. Autopsy specimens of striatal tissue from people with schizophrenia, normal controls, and psychiatr ic controls were obtained from the Maryland Brain Collection. Several abnormalities were noted in the schizophrenic group that were not pres ent in the normal or psychiatric controls. In schizophrenic tissue, th e density and/or proportion of symmetric synaptic profiles, particular ly those ending on spines, were lower in the caudate vs. the putamen, implying an imbalance in inhibitory synaptic transmission between thes e two structures. The density of perforated synaptic profiles, cortica l afferents thought to be involved in synaptic turnover and cognition, was lower in the striatum of the schizophrenic group compared to the control groups. The density of axodendritic synaptic profiles, particu larly of the asymmetric type, was decreased in the caudate, but not th e putamen, of a subset of schizophrenic cases that were nondyskinetic and off drugs (NDODS). The proportion of asymmetric axospinous synapti c profiles was elevated in the caudate of the NDODS cases in compariso n to normal controls. The variety of synapses affected in the schizoph renic group implies the involvement of several neuronal circuits. The alterations observed in the schizophrenic striatum were usually due to changes in the caudate, but not the putamen, which argues against dru g-related alterations. Since the striatum, particularly the caudate nu cleus, is involved in cognition and emotion, these neuroanatomical cha nges could underlie, in part, aspects of schizophrenic psychopathology . (C) 1998 Wiley-Liss, Inc.