Fujiwara K, Kunita K, Toyama H, Miyaguchi A
Department of Human Movement and Health, Graduate School of Medical Science, Kanazawa University, Japan.
Eur J Appl Physiol. 2001 Oct;85(6):527-32. doi: 10.1007/s004210100509.
We investigated the effect of increases in muscle afferent information from the shoulder girdle elevators on saccadic reaction time. Saccadic reaction time was measured under conditions of isometric voluntary contraction of the shoulder girdle elevators and vibratory stimulation of the trapezius. Saccadic reaction time was defined as the latency until the beginning of eye movement toward the lateral target, which was moved at random time-intervals in jumps of 20 degress amplitude. Eye movement was measured using the electro-oculogram technique. Muscle contraction force was set in 10% increments from 0% to 30% of maximal voluntary contraction (MVC), and vibration frequency was maintained at 100 Hz. Under voluntary contraction, the saccadic reaction time gradually shortened up to 30% MVC. Under vibration stimulation at 0% MVC, the reaction time shortened to the same degree as that under voluntary contraction at 30% MVC. Under conditions of combined vibratory stimulation and voluntary contraction, the reaction time was essentially identical to these values; namely, no additive effect in shortening of the reaction time was recognized. The results demonstrated that saccadic reaction times were remarkably shortened by increases in muscle afferent information from the neck extensors. We have discussed reasons for the lack of an additive effect and factors limiting shortening of reaction times.
我们研究了来自肩胛带提升肌的肌肉传入信息增加对眼跳反应时间的影响。在肩胛带提升肌等长自主收缩和斜方肌振动刺激的条件下测量眼跳反应时间。眼跳反应时间定义为朝向外侧目标开始眼动的潜伏期，该目标以20度幅度的跳跃在随机时间间隔移动。使用眼电图技术测量眼动。肌肉收缩力从最大自主收缩（MVC）的0%以10%的增量设置到30%，振动频率保持在100Hz。在自主收缩下，眼跳反应时间逐渐缩短至30%MVC。在0%MVC的振动刺激下，反应时间缩短到与30%MVC自主收缩时相同的程度。在振动刺激和自主收缩相结合的条件下，反应时间与这些值基本相同；即，未观察到反应时间缩短的相加效应。结果表明，来自颈部伸肌的肌肉传入信息增加可显著缩短眼跳反应时间。我们讨论了缺乏相加效应的原因以及限制反应时间缩短的因素。
