On a CRT display, analogue heart rate feedback of each beat was presented together with a target calculated from a subject's heart rate level. Twenty subjects received twenty-four 100-beat trials. All subjects were required to continue adjusting their heart rate around the target as close as possible under both immediate and 3-beat delayed feedback conditions. Half of the subjects received immediate feedback trials first, followed by delayed feedback trials, while the other half received trials in the reverse order. Results indicated that feedback delay disrupted the accuracy of heart rate control when subjects received delayed feedback after immediate feedback trials, and that feedback delay caused low-frequency oscillation in heart rate variability. Findings in this experiment suggest that voluntary control of heart rate can be understood from the viewpoint of motor skills learing.
This study was designed to examine whether the subjects could learn to discriminate their alpha activity from non-alpha activity by integrated alpha technique. A total of 26 subjects were assigned to either the experimental group or the yoked control group by pair-matching the amounts of alpha wave. Both groups received three 5 min feedback training sessions to increase the alpha activity. In these sessions, the experimental subjects were given contingent feedback signals to their amount of alpha wave, while the control subjects were given non-contingent feedback signals. In the pre-and post-feedback sessions, the subjects' discriminabilities of alpha activity, either presence or absence, were measured 60 times respectively. The results showed that the experimental subjects significantly improved their discriminative accuracy across the trials, although the yoked control subjects provided no improvement of accuracy. Noteworthily, the experimental subjects significantly increased their amount of alpha wave during the feedback sessions.
A system named Automated Spindle Analyzer (ASPA), which automatically detects sleep spindles and measures the mean amplitude, the mean frequency, the duration and the time of occurence of each spindle in real time, is described. It can also calculate the means, standard deviations and distributions of each parameter across the recording. Furthermore, it is possible to control experiments concurrently with analyzing sleep spindles by the system. Agreement between spindle detections obtained by visual scoring method and by the ASPA was relatively high; approximately 90%. The ASPA has advantages of low cost, portability and self-sufficiency. The utility of this system thus recommends it for the analysis of sleep spindles in laboratories and various other circumstances as well.