Abstract
Previous reports (Inamori, 1981, 1982) supported the hypothesis that biofeedback aided heart rate (HR) control is analogous to motor skill, because HR control was disturbed as a function of delay feedback length. The purpose of this report was to investgate what kind of motor task is the most appropriate model for self-control of HR. Three expriments, which were similar to the previous one except that skeletal responses were used instead of HR inter-beat intervals, examined the effects of delayed feedback on a tracking task. Subjects tracked the target under four feedback conditions: immediate, 1/2-beat constant delay, 1/2-beat variable delay, and 1-beat delay. Time on target and power spectra of response sequences were compared between conditions. The first motor response was sequential finger tapping, and the inter-tap intervals were sampled at the same inter-beat intervals as HR, but subjects could perceive when a tap occurred. As a result, only the 1/2-beat variable delay disturbed the tracking performance. The second motor response was slowly turning a fishing reel, and the time required for every 0.42 rotation of the reel were measured. In this experiment, subjects could not perceive when a response was sampled. However, results showed no different performance between immediate and 1-beat delay conditions, nor were they consistent with the case of HR. The last motor response was also reel turning, but each sampled time minus 800 msec was integrated and adapted as the controled interval. Results of this experiment were very consistent with those of HR in both tracking performance and power spectra of respoese sequences. The results of these three experiments suggest that the plant charactristic of HR control mechanism has an integral element, and that the perception of response occuring has no effect on HR control.
