[Animal experimental investigations for determining the duration of the "mechanical-effective period" of muscle action potentials and of the "electro-mechanical latency period" of "fast fibres" of external ocular muscles (author's transl)].

A report is given of an animal experimental study for determination of the duration of the "mechanical effective period" of the muscle fiber membrane action potential and the "electromechanical latency period" of "fast fibers" of the external ocular muscles in rabbits in vivo. The studies were carried out with an internationally standardized glass microelectrode technique. The statistical values are based on 250 tests employing the superposition technique. The mean "mechanical effective period" of the muscular fiber membrane action potential was determined with SE=0.52 ms, SD 0.08 ms. The confidence thresholds were 99% statistically reliable with 0.43 ms and 0.55 ms. According to these studies, the duration of the "mechanical effective period" of the "fast fibers" of the external ocular muscles was only one-third off the "mechanical effective period" of the skeletal muscles. The mean duration of the "electromechanical fast-fiber latency period" was calculated with SE=1.97 ms, SD=0.30 ms. The confidence threshold was 99% statistically reliable with 1.86 ms and 2.08 ms. The "electromechanical latency period" of the "fast fibers" of the external ocular muscles was therefore significantly less than the skeletal muscles, lying under the 50% limit of the "electromechanical latency period" of the analogous skeletal musculature. These studies permit determination of the most important electrophysiological parameters which define a threshold value of maximal speed in vision direction changes.