2012 年 50 巻 5 号 p. 417-425
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.