Two types of phase correction mechanism involved in synchronized tapping.

We clarify internal phase correction mechanisms affecting timing control in a synchronization tapping task. Synchronization error (SE) was directly controlled within 450-1800 ms of the inter stimulusonset interval (ISI) with our experimental method. Two types of internal phase correction mechanism became evident. The first showed a strong negative correlation between SE change and change in inter taponset interval (ITI), suggesting a simple negative feedback mechanism. This correlation was observed under all ISI conditions. The second type showed a larger response with a low negative correlation and was observed only with long (1200-1800 ms) ISIs. Only the second mechanism was inhibited in a dual task condition. These results suggest that there are two types of internal phase correction mechanism.