誘発電位におよぼす時間評価活動安定化の効果 外発性対内発性概念の検討

抄録

It has been widely reported that the late positive component (P₃) of Auditory Evoked Potentials (AEP) was elicited by the onset of task-relevant stimulus. It also has been reported that when the stimuli differ only in duration, the offset of task-relevant tone evokes the AEP with P₃. In this study, it was hypothesized that P₃ can be evoked by a task-irrelevant tone as well as by a task-relevant one if subject starts processing every tone as the task-relevant one from its onset. The task-relevant tone was a medium-duration tone and prior to the task, the subject was trained to anticipate the cessation of the medium-duration tone (600ms) without actual offset. Results showed that when the duration was short (300ms), P₃ was evoked by the offset of tone. However, when it was long (1200ms), P₃ was elicited at the time of the offset of the task-relevant tone. These findings were interpreted to mean that the termination of time estimation activity for the task-relevant tone evoked P₃ component.