Myklebust B M, Gottlieb G L
Medical College of Wisconsin, Milwaukee.
Child Dev. 1993 Aug;64(4):1036-45.
The stretch reflex is a spinal cord pathway between a muscle's stretch receptors and its own motor units. This reflex is thought to play an important role in normal motor function, because it is unique as a monosynaptic pathway, and because its hyperactivity is a hallmark of many motor disorders. We previously reported a difference in the stretch reflexes in healthy newborn infants and nonambulatory individuals with cerebral palsy (CP): these reflexes are characterized by responses from the stretched muscle and from the reciprocal or antagonist muscle. We proposed the existence of a functional spinal cord pathway that connects both agonist and antagonist muscles at a single joint. We hypothesized that this "reciprocal excitation" is a functional pathway of all newborn infants, which during the normal course of development of motor skills in infants is eliminated. If the CNS is damaged at birth, as in CP, the pathway of reciprocal excitation endures and is reinforced. In the current study of newborns, we recorded stretch reflex responses from all major muscle groups of the lower limb. This "irradiation of reflexes" is a normal phenomenon of the newborn CNS. This pathway becomes suppressed during normal maturation and control of coordinated limb movements.
牵张反射是肌肉的牵张感受器与其自身运动单位之间的脊髓通路。这种反射被认为在正常运动功能中起重要作用，这是因为它作为单突触通路是独特的，还因为其活动亢进是许多运动障碍的一个标志。我们之前报道了健康新生儿和非行走型脑瘫（CP）个体的牵张反射存在差异：这些反射的特征是来自被拉伸肌肉以及其对侧或拮抗肌的反应。我们提出存在一条功能性脊髓通路，该通路在单个关节处连接主动肌和拮抗肌。我们假设这种“交互性兴奋”是所有新生儿都具有的功能性通路，在婴儿运动技能的正常发育过程中该通路会被消除。如果中枢神经系统在出生时受损，如在脑瘫中，交互性兴奋通路会持续存在并得到强化。在当前对新生儿的研究中，我们记录了下肢所有主要肌肉群的牵张反射反应。这种“反射扩散”是新生儿中枢神经系统的一种正常现象。在正常成熟以及协调肢体运动的控制过程中，该通路会受到抑制。
