Abstract
Electromyographic recordings of consecutive discharges of single motor units were obtained from the vastus lateralis muscle and/or the gastrocnemius muscle of blindfolded (test) and unblindfolded (control) dogs. The recordings of discharges were made on both animals while they remained standing under two different conditions, on a fixed flat plane and on a moving inclined board. The moving inclined board was put into motion (about 1°/sec. angular velocity) by fixing one of its ends (caudal end of animal) to act as a fulcrum, while the other end (cranial end of animal) was free to move up and down (O° to about 10° angle of inclination) continuously. The Tokizane's τ-S correlation and the Nomura's time-serial analysis of the discharge-intervals were employed to analyze the optical adjustment. The results obtained are summerized as follows. 1. The optical adjustment prevents the standard deviation of discharge-intervals from augmenting (Figs. 1 and 7). 2. The optical adjustment suppresses both the appearance of the exaggerated slow undulation (Figs. 2, 3, 8 and 9) and the occurrence of the statistically significant (α=0.05) periodic H-type fluctuation (Figs. 4 and 10). 3. The optical adjustment facilitates the maintenance of the negative correlation between adjoining discharge-intervals (Figs. 5 and 11). 4. The equilibrium of the standing on a moving inclined plane is more dependent upon the optical adjustment than that on a fixed flat plane. From these results, the possibilities were discussed that optical impulses would contribute to the integrity of the cerebellum and brainstem, and that it would facilitate the gamma motor system through the nervous structures of the higher level.
