Twenty-five schizophrenic patients diagnosed by DSM-III-R underwent event-related potentials and magnetic resonance imaging scans. Latency and amplitude of P300 waveform were measured using an auditory odd-ball paradigm. Anterior and... more
Twenty-five schizophrenic patients diagnosed by DSM-III-R underwent event-related potentials and magnetic resonance imaging scans. Latency and amplitude of P300 waveform were measured using an auditory odd-ball paradigm. Anterior and posterior volumes of the superior temporal gyrus and medial temporal structure were measured from contiguous coronal images using the level of the mammillary body as an anatomical landmark. Principal component analysis of P300 latency and amplitude disclosed two orthogonal independent factors each: overall latency and residual, and amplitudes from posterior and anterior recordings, respectively. Structural volumes consisted of four orthogonally independent factors: left superior temporal volume, anterior medial temporal volume, right superior temporal volume, and posterior medial temporal volume. The factor score of the P300 amplitude from posterior recordings correlated with the factor score of volumetric changes in the anterior medial temporal structu...
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Reduced amplitude of the P300 component has been reported consistently in patients with neurological and psychiatric disorders. It is unclear, however, how such patients' cognitive dysfunction is related to their P300 abnormality.... more
Reduced amplitude of the P300 component has been reported consistently in patients with neurological and psychiatric disorders. It is unclear, however, how such patients' cognitive dysfunction is related to their P300 abnormality. Further basic knowledge regarding neural substrates for P300 generation is required for gaining an understanding of the pathological significance of the P300 amplitude reduction. To determine the brain
Research Interests: Computed Tomography, Brain and Cognitive Development, Right Hemisphere Functions, Evoked Potentials, Humans, and 9 moreMale, Task Performance, Single Photon Emission Computed Tomography, Adult, Regional Cerebral Blood Flow, Brain Structure, Task Performance and Analysis, Blood Flow Velocity, and Acoustic Stimulation
Single photon emission computed tomography (SPECT) images were obtained in 10 right-handed neuroleptic-treated schizophrenic patients and 10 healthy volunteers using Tc-99m-hexamethyl-propylenamine oxime (Tc99m-HMPAO) during performance... more
Single photon emission computed tomography (SPECT) images were obtained in 10 right-handed neuroleptic-treated schizophrenic patients and 10 healthy volunteers using Tc-99m-hexamethyl-propylenamine oxime (Tc99m-HMPAO) during performance of the Wisconsin Card Sorting Test (WCST) and at rest. None of the patients showed severe impairment on the WCST. The patient group showed a statistically insignificant trend to incur more unique errors. In both the patient and control groups, the left lateral prefrontal blood flow significantly increased during the WCST, as compared to during resting conditions. Only during the WCST, the patient group showed a significant regional cerebral blood flow (rCBF) decline in the left medial prefrontal cortex, as well as in the right side under both the test and resting conditions. This left medial prefrontal rCBF during the WCST correlated positively with the number of unique errors, although this correlation was statistically insignificant. The right fronto-parietal rCBF was significantly increased in the patient group under both the test and resting conditions. Moreover, in the left hippocampal region, the patient group showed a significant rCBF increase under resting conditions.
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Research Interests:
Research Interests: Engineering, Image Processing, Medical Image Processing, Data Compression, Telemedicine, and 16 moreCluster Computing, Computer assisted orthopaedic surgery, Dynamic Load Balancing, Humans, Operating Room, Three Dimensional Imaging, Total Hip Replacement, Online Systems, High performance computer, Range of Motion, Remote Access, Computer assisted surgery, Internet, *Radiographic Image Enhancement, Cluster System, and Computing Methodologies
Regional cerebral blood flow was evaluated using Tc99m-HMPAO SPECT in 10 medicated patients with schizophrenia and 9 healthy volunteers. There were no prefrontal regions in the patient group with lower regional indices than in the control... more
Regional cerebral blood flow was evaluated using Tc99m-HMPAO SPECT in 10 medicated patients with schizophrenia and 9 healthy volunteers. There were no prefrontal regions in the patient group with lower regional indices than in the control group. However, in the left hippocampal region, relative blood flow was significantly increased in the patient group compared with the control group. Furthermore, there was a relative increase in blood flow in the left basal ganglia of the patient group. A negative correlation coefficient was calculated between the relative blood flow in the left middle prefrontal cortex and the severity of the blunted affect, as well as between the relative blood flow in the left basal ganglia and the severity of the anhedonia-asociality. These findings indicate that prefrontal hypoactivity is not invariably present in all schizophrenics and that left basal ganglial hyperactivity may be associated with the effects of antipsychotic treatment and clinical improvement. Moreover, the left hippocampal hyperactivity may correspond to left limbic dysfunction in schizophrenia.
Research Interests: Cognitive Science, Schizophrenia, Prefrontal Cortex, Brain Mapping, Hippocampus, and 17 moreBrain, Humans, Cerebral Cortex, Chronic Disease, Male, Social Isolation, Clinical Sciences, Single Photon Emission Computed Tomography, Adult, Oximes, Blood Flow, Basal ganglia, Regional Cerebral Blood Flow, Correlation coefficient, Neurosciences, Control Group, and Psychiatric Status Rating Scales
Research Interests: Schizophrenia, Principal Component Analysis, Electroencephalography, Delusions, Multivariate Analysis, and 13 moreBiological Sciences, Biological Psychiatry, Evoked Potentials, Humans, Hallucinations, Female, Male, Adult, Biological markers, Cognition disorders, Acoustic Stimulation, Severity of Illness Index, and Psychiatric Status Rating Scales
Regional cerebral blood flow (rCBF) was measured with technetium-99m hexamethylpropyleneamine oxime single photon emission computed tomography in 38 neuroleptic-treated schizophrenic patients. To improve the validity of the evaluation of... more
Regional cerebral blood flow (rCBF) was measured with technetium-99m hexamethylpropyleneamine oxime single photon emission computed tomography in 38 neuroleptic-treated schizophrenic patients. To improve the validity of the evaluation of symptomatology, we applied findings previously derived in a principal component analysis (PCA) of the Positive and Negative Syndrome Scale. The PCA had disclosed five orthogonal independent symptom structures (i.e., negative, hostile/excited, thought disordered, delusional/hallucinatory, and depressive components), and obtained factor scores for 70 schizophrenic subjects, including the present sample. Stepwise regression analysis elucidated some of the cortical regions in which relative rCBF predicted the severity of symptoms--namely, lateral and orbital prefrontal, lateral temporal, inferior parietal, and medial temporal regions. Findings suggested that symptom structures derived from PCA could prove helpful in elucidating the pathophysiology of neural mechanisms.