Koceja D M, Kamen G
Department of Kinesiology, Indiana University, Bloomington 47405.
Exp Brain Res. 1991;86(2):433-9. doi: 10.1007/BF00228969.
In an effort to more fully investigate spinal reflex pathways in humans, we measured the isometric force-time curve of the patellar (PTR) and Achilles (ATR) tendon-tap reflex in 12 college age subjects. We also conditioned the tendon jerk with a contralateral or ipsilateral tendon-tap stimulus, to ascertain the effects of segmental inputs on crossed-spinal reflex activity. The conditioning stimulus preceded the test reflex by 25, 40, 55, 70, 85, 100, 115, 130 or 145 ms. The results demonstrate that a tap to the contralateral patellar tendon produced long-latency excitation of quadriceps motoneurons, but a tap to the contralateral Achilles tendon produced short-latency facilitation and long-latency inhibition of the triceps surae motoneurons. Also, a conditioning tap to the contra- or ipsilateral patellar tendon produced a brief short-latency facilitation that was followed by a distinct, long-latency inhibition of triceps surae motoneurons. These results demonstrate that motoneuron excitability changes can be produced as a result of ispi- and contralateral segmental inputs. Moreover, these excitability changes may be long-lasting and only appear after a relatively long-latency. Several neurophysiological mechanisms are proposed to contribute to these changes.
为了更全面地研究人类脊髓反射通路，我们测量了12名大学生年龄受试者的髌腱（PTR）和跟腱（ATR）叩击反射的等长力-时曲线。我们还用对侧或同侧的腱叩击刺激来调节腱反射，以确定节段性输入对交叉脊髓反射活动的影响。调节刺激在测试反射之前25、40、55、70、85、100、115、130或145毫秒。结果表明，对侧髌腱叩击可产生股四头肌运动神经元的长潜伏期兴奋，但对侧跟腱叩击可产生小腿三头肌运动神经元的短潜伏期易化和长潜伏期抑制。此外，对侧或同侧髌腱的调节性叩击可产生短暂的短潜伏期易化，随后是小腿三头肌运动神经元明显的长潜伏期抑制。这些结果表明，同侧和对侧节段性输入可导致运动神经元兴奋性改变。此外，这些兴奋性改变可能是持久的，并且仅在相对较长的潜伏期后出现。提出了几种神经生理机制来解释这些变化。
