MRI-SPECT and PET-EEG findings on brain dysfunction in schizophrenia

1. In this article the author reviews a series of investigations on brain dysfunction in untreated schizophrenics using manumotor and music listening tasks as activation paradigms. Methods involved were EEG mapping, Single Photon Emission Computerized Tomography (SPECT; Xenon-133 inhalation method), Magnetic Resonance Imaging (MRI) and Positron Emission Tomography (PET; 11-2-Deoxyglucose as tracer). 2. Major signs of brain dysfunction yielded a "nonreactivity" on both motor and music stimulation in patients displaying marked negative symptomatology, as shown consistently by EEG Mapping, SPECT and PET. In contrast, first-break patients with predominant "positive" and without underlying negative symptoms showed signs of "normal" to "diffuse hyperactivation" on such stimulations, as demonstrated by EEG and SPECT imaging methods. 3. Interestingly, MRI planimetry of the size of the corpus callosum (CC) corroborated the above findings, showing a significantly larger CC in "positive" than "negative" patients. 4. Together with functional imaging findings of other working groups and recent neuropathological theories we finally raise some speculative neurophysiological hypotheses on brain dysfunction in subgroups of schizophrenics, which might have direct implications for treatment and follow-up of these patients.