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Biomedical subjects

R Taniguchi

Publications and source records attributed to R Taniguchi.

At least 55 records · Page 3Linked to original sources
PubMed1978

Disturbances of rhythm formation in patients with Parkinson's disease: part II. a forced oscillation model.

The origin of the characteristic disturbances of rhythm formation in patients with Parkinson's disease (the hastening phenomenon) was discussed, using a second-order system of the periodic response. The input signal was regarded as a pulse series of a Dirac function. The output process of the system had maximal errors of response at input frequencies of f = omega0/n (n = 1, 2, . . .), where omega0 was the intrinsic frequency of the system. Damping coefficient epsilon represented a function of an inhibitor against these maximal errors and the errors diverged to infinity when epsilon = 0. The solution of this forced oscillation system indicated that the intrinsic oscillation of the system has a possibility to be excited at these critical frequencies f = omega/n. Inferred from data on the tapping test, the frequency of an intrinsic oscillation was 5 Hz in the central nervous system, then the critical frequencies were predicted 5/n = 5, 2.5, . . . Hz. On the tapping test the errors of response become maximum around 2.5 and 5 Hz (taps per second), and their peak heights increased from the minimum in well trained normal subjects to the maximum in patients. An inhibitory mechanism against the maximal error would function well, i.e. epsilon greater than 0, in normal subjects but so insufficiently (epsilon leads to 0) in patients that the excited intrinsic oscillation would control their response directly. Thus some patients could no longer maintain a synchronous tapping response at 2.5 Hz or 5 Hz and showed a hastened tapping of 5 6 Hz independent of the signal frequency.

Central Nervous System↗
PubMed1977

Reaction time in simultaneous motions.

EMG-RTs of biceps and triceps brachii muscles were measured in 3 different tasks: isolated motions, flexion or extension of either forearm; bilateral symmetrical motions, flexion or extension of both forearms; bilateral opposite motions, flexion of a forearm and extension of the other. EMG-RTs of opposite motions were slower than those of isolated and symmetrical motions, EMG-RTs of symmetrical motions were nearly equivalent to those of isolated motions. Simplicity and complexity of simultaneous motions are discussed.

Adult↗
PubMed1977

Reaction time in bimanual simultaneous motions.

Electromyographically determined reaction times (EMG-RTs) of the finger flexor and extensor of both forearms were measured for four different motions: inward (task 1), flexion of both wrists; outward (task 2), extension of both wrists; to the left (task 3), extension of the left wrist and flexion of the right; and to the right (task 4), flexion of the left and extension of the right. The EMG-RTs were shorter and synchronization errors in terms of left to right differences of EMG-RTs were smaller in tasks 1 and 2 than in tasks 3 and 4. Comparing the flexors and the extensors, the extent of prolongation of EMG-RTs in tasks 3 and 4 differed significantly on the left side, being larger in the flexor than in the extensor, but there was no difference in the extent of prolongation between the flexor and the extensor on the right. It was suggested that the timing of initiation of movements in simultaneous motions was primarily determined by the pattern of muscle coupling in both limbs, and not by the direction of movements. The steadiness of motor function and of the right hand in right-handed subjects was also discussed in regard to hand preference.

Adult↗
PubMed1976

Preferred hand and steadiness of reaction time.

RT and its left/right difference of both biceps muscles were measured by electromyogram (EMG) in the bilateral simultaneous flexion of elbows using 11 left- and 13 right-handed subjects under four conditions which were combinations of two factors; warning signal; presence or absence of a fore-period, and position of limbs; elbow 90 degrees or 135 degrees. EMG-RT and its left/right difference were influenced by these factors. The effects of warning and position of limbs were not the same on the preferred and non-preferred hands. It was assumed that EMG-RTs of biceps in the preferred hand were less influenced by these experimental conditions.

Acoustic Stimulation↗