[en] The purpose of this study is to find the correlation between middle latency auditory evoked potentials (MLAEP) and sound activated single photon emission computed tomography (SPECT) studies. This study was performed on six normal right-handed volunteers with a mean age of 35.2±7.6 years, using the split-dose technique. First, a SPECT study was performed on subjects in blinded, awake and silent states. After bilateral ears were stimulated with a click sound, MLAEP and a second SPECT study were performed. Subtraction of the first SPECT from the second SPECT revealed a statistically significant increase of cerebral blood flow (CBF) in the bilateral superior temporal region. Bilateral Na amplitudes of MLAEP had a statistically significant and good correlation with the percentages of CBF changes in the bilateral superior temporal region. The superior temporal cerebral blood flow activation can be expressed by electrophysiological activation. Moreover, correlation during the left Na components and left frontal and occipital lobe are discussed. (author)

[en] The activated cerebral regions and the timing of information processing in the hemispheres was investigated using event-related potentials (ERP) and regional cerebral blood flow (rCBF) as the neurophysiological indicators. Seven men and one woman (age 19-27 years) were asked to categorize two-syllable Japanese nouns (verbal condition) and to judge the difference between pairs of rectangles (spatial condition), both tests presented on a monochrome display. In the electroencephalogram (EEG) session, EEG were recorded from 16 electrode sites, with linked earlobe electrodes as reference. In the positron emission tomography (PET) session, rCBF were measured by the ¹⁵O-labeled H₂O bolus injection method. Regions of interest were the frontal, temporal, parietal, occipital and central lobes, and the entire cerebral hemispheres. When the subtracted voltages of the ERP in homologous scalp sites were compared for the verbal and spatial conditions, the significant differences were at F7·F8 and T5·T6 (the 10-20 system). The latencies of the differences at T5·T6 were around 200, 250 and 320 ms. A significant difference in rCBF between the verbal and spatial conditions was found only in the temporal region. It was concluded that early processing of information, that is, registration and simple recognition, may be performed mainly in the left temporal lobe for verbal information and in the right for spatial information. (author)

[en] Although a number of radiological studies have suggested that brains of patients suffering from schizophrenia have morphological abnormalities, the results are inconsistent. In the present study, in order to examine the brain, morphological features of homogeneous schizophrenics' brain magnetic resonance imagings (MRI) were taken, before neuroleptic treatment, from subjects suffering from disorganized-type schizophrenia, (DOS) during their first episodes. Results showed that DOS had significantly smaller indices for bilateral frontal gray matter (GM), left hippocampal formation (HF), left parahippocampal gray matter (PHGM) and left cingulate gyrus gray matter (CGM) than normal controls. These findings support the previous computed tomography (CT) and MRI studies on schizophrenic brains, although the subjects were not defined as disorganized-type, and may suggest the involvement of a neurocircuit between the bilateral frontal lobe and the left side of limbic system in the first-episode DOS group. (author). 54 refs

[en] The width of interhemispheric fissure, lateral ventricles and third ventricle were measured using cranial computed tomography (CT; linear method) in 45 elderly inpatients with chronic schizophrenia and in 28 age-matched control subjects. Twenty-three patients were men and 22 were women. In addition, Mini-Mental State Examination, Brief Psychiatric Rating Scale (BPRS) and a subclass of BPRS were undertaken in all patients. There is a significant enlargement of the maximum width of the interhemispheric fissure (in both male and female) and a significant enlargement of ventricular system (more severe in men than in women) in aged schizophrenics, as seen with CT, compared with normal controls. These findings are consistent with previous studies of non-aged schizophrenic patients. Based upon the relation between psychiatric symptoms and CT findings, the most striking is a significant negative correlation between the third ventricle enlargement and the positive and depressive symptoms in all patients. This result suggests that the advanced third ventricle enlargement may decrease these symptoms in aged schizophrenics. (author)

[en] We examined patterns of regional cerebral blood flow (rCBF) abnormalities in 18 patients with major depressive disorder in late life using single photon emission computed tomography (SPECT) and ^99mTc-hexamethyl-propylenamine oxime (^99mTc-HMPAO). Compared with 13 age-matched controls, relative rCBF was significantly decreased bilaterally in the anterior cingulate gyrus, the prefrontal cortex, the temporal cortex, the parietal cortex, the hippocampus and the caudate nucleus. However, it was not correlated with the severity of depression or global cognitive dysfunction. In 10 patients with a prolonged depressive episode or prolonged residual symptoms (the refractory subgroup), robust and extensive decreases in rCBF were found compared with controls and the rCBF decreased significantly in the anterior cingulate gyrus and the prefrontal cortex compared with that in the non-refractory subgroup. In the non-reflactory subgroup, rCBF decreased significantly in the caudate nucleus and tended to decrease in the anterior cingulate gyrus compared with controls. These findings indicate that dysfunction of the limbic system, the cerebral association cortex and the caudate nucleus may be implicated in late-life depression and that robust and extensive hypoperfusion, especially in the anterior cingulate and the prefrontal regions, may relate to refractoriness or chronification of depression. (author). 60 refs