The purpose of this study is to examine how human performance organized by motor learning is reorganized through changes in the central program and structural parameter by using a tracking task of serial pattern. On the one hand, the subjects who had to adjust themselves to the changed central program (program group) tried to execute the corresponding switch responses coincident with light onsets in 20 trials in the first half and tried to complete perfectly with anticipatory response in 20 trials in the second half. On the other hand, the subjects who had to adjust themselves to the changed structural parameter (parameter group) tried to execute the corresponding switch responses coincident with light onsets in 40 trials. The serial patterns which subjects tracked were 352415 in the program group and 352415 in the first half of the parameter group and 352451 in the second half of that group. The stimulus interval (100 ms) and the interstimulus interval (400 ms) were always constant. The subjects were 20 right-handed female students, being randomly assigned to the 2 groups with 10 subjects respectively. In both groups, the proportion of correct responses amounted approximately to 7090% of the total response in the first half. Both groups increased the correct and anticipatory responses in the final phase of the first half. The program group, however, remarkably decreased the correct responses (7.03%) and markedly increased the anticipatory responses (42.16%) in the final phase of the second half. The program group in the first half was different from the one in the second half in structuring its own performance. In the parameter group, on the other hand, the performance in the final phase of the second half (anticipatory response : 25.00%) was higher than that of the first half (anticipatory response : 4.46%) although the performance without anticipatory response in the initial phase of the second half was lower than the one in the final phase of the first half. This finding was taken as an order through fluctuation.
Human femora obtained from a cadaver of a 70-year-old man were examined by means of bone histometry, image-analysis on X-ray radiographs and a mechanical strength test in order to investigate the effects of disuse on the femora. The patient had been bedfast for seven months until his death because of an amputation of the left lower leg due to a diabetic intractable ulcer on the foot caused by a burn. Other detail records of the medical and the life-style history were also examined. A marked atrophy of the muscles of the hip and thigh was observed on the amputated side. The macroscopic shape and proportion of the femora were not significantly different between both sides. The results of bending strength test at the mid shaft, disclosed a marked mechanical fragility on the amputated side. The cortical bone area in the shaft showed no significant difference between both sides. However, the degree of bone loss was more pronounced at the anterior region of both shafts. The trabecular bone at the femoral head showed a marked atrophy on the amputated side, especially at the principal compressive group of the trabecular bone. This atrophy was thought to be due to the absence of the compressive stress because of the disuse caused by the amputation. A trabecular bone atrophy was also observed on the normal side and its degree of atrophy was greater than that of agematched values. The multiple systemic factors such as the diabetes and the bedfast condition might had influenced on the bone metabolism in this case, therefore the careful examination of the systemic conditions was required to disclose the effects of local mechanical conditions on the bone metabolism.