[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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Dysfunction of voluntary motor movements in schizophrenia patients has been clinically observed .Ithas been suggested that schizophrenia patients have difficulty in programming voluntary movements such as preparation and intention to act. Recording of Bereitschaftspotentials(BP)can provide neurophysiological measure of voluntary movements and can index motor preparatory functuion. Previous BP studies in schizophrenia patients seem to be contradictory in terms of several points. Thus, we assessed the BP generated prior to a simple finger task and a complex finger task in11schizophrenia patients with positive symptoms, 13schizophrenia patients with negative symptoms and11normal control subjects. All schizo phrenia patients have no drug induced parkinsonism and tardive dyskinesia. We compared the BPs in two different schizophrenia groups with the corresponding data from the control group. To evaluate actual motor performance, we also employed finger tapping task and pegboard tasks. The most prominent result was shown in the complex finger task. During the complex finger task requiring sequential motor processes, we found a significantly smaller late BP in schizophrenia patients with negative symptoms and a significantly larger late BP in schizophrenia patients with positive symptoms, as compared to late BP in normal healthy subjects. During the simple finger task, we found only a significant difference; schizophrenia patients with negative symptoms showed a significantly smaller late BP than that in normal healthy subjects.Both of these patient groups showed poor motor performance in the finger tapping and pegboard tasks. These abnormal neurophysiological changes of BP in schizophrenia patients may be explained by dysfunction of sensorimotor and supplementary motor area generating the BP. Furthermore, since late BP is related to motor preparatory function, we hypothesize that:1)an inappropriate level of BP particularly during the complex finger task requiring more motor preparatory function in schizophrenia patients may cause the poor motor perfor mances;2)schizophrenia patients have impaired optimal control of motor preparatory function The present study may provide further support for motor dysfunction in schizophrenia.

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