When random dot patterns moving at different directions are superimposed, observers perceive transparent surfaces sliding over each other at different depth planes. This phenomenon is called transparent motion perception. In this study, neuromagnetic field during a transparent motion perception task were measured by 306-channel whole-head MEG to investigate the brain mechanism on determination of perceptual depth order in transparent motion processing. We have analyzed the time courses of event-related synchronization and desynchronization(ERS/ERD)of the magnetoencephalography using time-frequency analysis. For the interpretation of MEG data, furthermore, eye movements during the task were measured and behavioral indicators showing the latency of transparent motion perception were determined from the result of eye movements measurement. According to the ERS/ERD analyses, it was found that the ERD in the alpha and beta bands and the ERS in the theta band were observed in all subjects. Results also show that ERDs have a significant difference between transparent motion task and one-way coherent motion task. By comparing with the latencies of the behavioral indicators, these results suggest that ERD reflects the brain activities to the determination of perceptual depth order in transparent motion perception.

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The purpose of this study is to utilize the viscoelastic model of human body for evaluation of sprint spike shoes from the view point of sprint performance. Subjects wore some spike shoes and performed vertical continuous hopping by only ankle joint extension. Then as the simulation model of landing shock wave, we constructed viscoelastic model by mass-spring-damper system. As the results, viscoelastic parameters are corresponding to the variation of actual movement in crural. And these parameters change by wearing spike shoes, there is a possibility that these model parameters are evaluation indexes of spike shoes.

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Visual evoked potentials (VEPs) are widely used for the analysis and the diagnosis of the brain function on visual system. Since the accuracy of analysis depends on the quality of VEP record, the medical doctors and/or medical technologists always pay attention to the state of recording. In this study, the real-time evaluation system for VEP recording was newly developed. The system displayed the information for the characteristic parameters of VEPs, contaminated artifacts affecting VEP recording and the appearance of background EEG activity in real-time during the recording. Tendency of the VEP characteristics was also comparable with the past VEP records in the data base. Blink artifacts, electromyographic (EMG) artifacts and posterior alpha wave were detected for evaluating the state of subjects. Developed system was applied to VEP recordings of ten healthy adults, then the effectiveness of the proposed system was investigated. Results were revealed that the system achieved the quality of VEP recording with sufficient level and reduced the laborious and time consuming task during the recording. The developed system will be useful as an assistant tool in VEP recordings.

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